SafeWork NSW v Danrae Remedial Services Pty Ltd

[2025] NSWDC 70

District Court

New South Wales

• Amendment notes

Medium Neutral Citation:

SafeWork NSW v Danrae Remedial Services Pty Ltd [2025] NSWDC 70

Hearing dates:

10, 11, 12, 13 and 14 February 2025

Date of orders:

18 March 2025

Decision date:

18 March 2025

Jurisdiction:

Criminal

Before:

Scotting DCJ

Decision:

1   I am satisfied beyond reasonable doubt that the prosecutor has proved the elements of the offence.

2   I find the defendant guilty of the s 32 offence.

Catchwords:

CRIME – prosecution – work health and safety – duty of persons undertaking business – duty of employer – risk of death or serious injury – injury to worker

Legislation Cited:

Interpretation Act 1987

Occupational Health and Safety Act 2000

Work Health and Safety Act 2011

Cases Cited:

Baiada Poultry Pty Ltd v R (2012) 246 CLR 92

Bulga Underground Operations v Nash [2016] NSWCCA 37

Carrington Slipways Pty Ltd v Callaghan (1985) 11 IR 467

Collins v State Rail Authority of New South Wales (1986) 5 NSWLR 209

Davis v Langdon [1911] 11 SR (NSW) 149

Director of Public Prosecutions v JCS Fabrications Pty Ltd and JMAL Group Pty Ltd [2019] VSCA 50

Director of Public Prosecutions v Vibro-Pile (Aust) Pty Ltd (2016) 49 VR 676

Dunlop Rubber Australia Ltd v Buckley (1952) 87 CLR 313

Federal Commissioner of Taxation v Consolidated Media Holdings Ltd (2012) 250 CLR 503

Genner Constructions Pty Ltd v WorkCover Authority of New South Wales [2001] NSWIRComm 267

Grasso Consulting Engineers Pty Ltd v SafeWork NSW [2021] NSWCCA 288

Inspector Ching v Bros Bins Systems Pty Ltd [2004] NSWIRComm 197

Kirk v Industrial Court of New South Wales (2010) 239 CLR 531

Laing O’Rourke (BMC) Pty Ltd v Kirwin [2011] WASCA 117

Nelson v John Lysaght (Australian Ltd) (1975) 132 CLR 201

R v Board of Trustees of the Science Museum [1993] 1 WLR 1171

R v Commercial Industrial Construction Group Pty Ltd (2006) 14 VR 321

R v Nelson Group Services (Maintenance) Ltd [1998] 4 All ER 332

Re Bolton; Ex Parte Beane (1987) 162 CLR 514

Royall v The Queen (1991) 172 CLR 378

SafeWork NSW v Tamex Transport Services Pty Ltd [2016] NSWDC 295

Saunders Civilbuild Pty Ltd v SafeWork NSW [2023] NSWCCA 261

Simpson Design and Associates Pty Ltd v Industrial Court of New South Wales [2011] NSWCA 316

Slivak v Lurgi (Aust) Pty Ltd (2001) 205 CLR 304

Smith v Broken Hill Pty Ltd (1957) 97 CLR 337

Tangerine Confectionery Ltd and Veolia ES (UK) Ltd v R [2011] EWCA Crim 2015

Thiess Pty Ltd v Industrial Court of New South Wales (2010) 78 NSWLR 94

WorkCover Authority of New South Wales v Kellogg (Aust) Pty Ltd [1999] NSWIRComm 453

WorkCover Authority of New South Wales v Kirk Group Holdings Pty Ltd (2004) 135 IR 166

WorkCover Authority of NSW v Atco Controls Pty Ltd (1998) 82 IR 80

Texts Cited:

Australian Standard 3760:2010 In-service safety inspection and testing of electrical equipment and RCDs

Australian Standard 60079.10.1 Classification of Hazardous Areas

SafeWork NSW Code of Practice Construction Work 2019

SafeWork NSW Managing the Risk of Hazardous Chemicals - Code of Practice

Category:

Principal judgment

Parties:

SafeWork NSW (Prosecutor)
Danrae Remedial Services Pty Ltd (Offender)

Representation:

Counsel:
M Scott (Prosecutor)
I Latham (Offender)

Solicitors:
Legal, Department of Customer Service (Prosecutor)
Wotton Kearney (Offender)

File Number(s):

2023/168134

Publication restriction:

None

Judgment

Introduction

1. Danrae Remedial Services Pty Ltd (Danrae) has pleaded not guilty to an offence that as a person with a health and safety duty under s 19(1) Work Health and Safety Act 2011 (the Act) Act that it failed to comply with that duty and thereby exposed Zach Reid and Drew Bunyan (the workers) to a risk of death or serious injury, contrary to s 32 of the Act.

2. On 12 November 2021 the workers were applying a waterproofing membrane to the third-floor balcony of a townhouse in Wilson Street, Botany (the site). The task involved applying Ardex WA98 Adhesive (the adhesive), a highly flammable substance, to membrane sheets and the floor of the balcony and then sticking the membrane sheets to the floor. Where the edges of the membrane sheets overlapped, it was intended to use a Leister Triac-ST Heat Gun (the heat gun) to heat weld them together. The heat gun could reach temperatures of up to 700^oC. It was raining at the time of the work and Mr Bunyan used the heat gun to dry areas of the floor so that the adhesive would stick. The heat gun was left switched on, close to where the work was being undertaken. At about 9.00am, Mr Reid was using a roller to apply the adhesive to membrane sheets and the floor. When he placed the roller back into a bucket containing the decanted adhesive, the vapour from the adhesive ignited and a flash fire engulfed Mr Reid causing burns to his lower legs.

Issues

3. Danrae admitted that it owed a duty to the workers pursuant to s 19(1) of the Act. The issues in the case are:

1. Did the defendant fail to comply with its health and safety duty by failing to take the steps particularised in [10] of the Summons? (Element 2)

2. Did the defendant’s breach of duty expose the workers to a risk of death or serious injury? (Element 3)

3. Was the heat gun the source of ignition for the fire?

4. Issue 3 is relevant to penalty only, and need only be considered if I am satisfied beyond reasonable doubt on Issues 1 and 2. I must also be satisfied beyond reasonable doubt of Issue 3 because it is potentially an aggravating factor on sentence.

Summary of conclusions

5. For the reasons that follow, I am satisfied beyond reasonable doubt that the defendant failed to take some of the reasonably practicable steps to ensure the health and safety of the workers particularised in [10] of the Summons, and that those failures exposed the workers to a risk of death or serious injury. It follows that I find the defendant guilty of the s 32 offence.

6. I am also satisfied beyond reasonable doubt for the reasons at [182] – [214] that the heat gun was the ignition source of the fire and that fact will be taken into account on sentence.

The Evidence

7. The evidence consisted of the tender of a large volume of documents and oral evidence from the following witnesses:

1. Inspector Selena Scott;

2. Darren Luce, a project manager employed by Danrae;

3. Daniel Caruana, the sole director of Danrae;

4. Zach Reid;

5. Drew Bunyan;

6. Inspector Tore Grillo, State Inspector for the Dangerous Goods Team of SafeWork NSW;

7. William Hunt, chemical engineer qualified as an expert by the prosecutor; and

8. Belinda Jones, forensic fire investigator qualified as an expert by Danrae.

Credit

8. Before turning to finding facts based on the evidence, it is necessary to make some findings about the credit of the witnesses called to give evidence.

Prosecution witnesses

9. Inspector Scott attended the scene of the incident and was involved in the initial investigation of the incident and issuing prohibition and improvement notices to Danrae. No issue was taken with Inspector Scott’s credit and I accept her evidence.

10. At the time of the incident Mr Luce was employed as a supervisor. The prosecutor relied on the transcript of a recorded interview between Mr Luce and Inspectors Barrie and Ball conducted on 31 March 2022, as his evidence in chief. That transcript is difficult to follow because Mr Luce was garrulous in answering those questions, and that presentation continued when he was called as a witness.

11. Mr Caruana presented as a witness who was being deliberately vague in answering counsel for the prosecutor’s questions. Mr Caruana asserted things in his s 155 responses and in his evidence, which were objectively untrue. For example, in his s 155 response he asserted that the incident occurred because Mr Reid erroneously left the heat gun on when that was contrary to Danrae’s “protocols and procedures”. For reasons I will come to, the heat gun was not identified as an ignition source in Danrae’s Safe Work Method Statement (SWMS), in force at the time of the incident. In his evidence in chief, Mr Caruana tried to retreat from his initial answer, and equivocated on his view of the cause of the incident until his s 155 response was squarely put to him. I am not satisfied that I should accept Mr Caruana’s evidence because I formed the impression that he was prepared to, and did, tailor his evidence to suit Danrae’s purposes.

12. Mr Reid was also an unsatisfactory witness. I formed the view that the answers he provided in his notebook interviews with Inspector Scott and his recorded interview with Inspectors Barrie and Ball on 25 March 2022, were more reliable than his oral evidence. He appeared to be concerned about giving evidence contrary to Danrae’s interests. He presented as guarded and his lack of recall of some events was strained. I note that after the incident, he was given a verbal warning for failing to comply with procedures and then almost instantly promoted. I have some reservations in accepting parts of Mr Reid’s evidence.

13. Mr Bunyan frankly told the Inspectors during his recorded interview that he had some learning difficulties and that he spent extra time to make sure that he understood things like safety data sheets (SDS) for relevant products. His presentation as a witness was consistent with that background. I also found his earlier answers to the Inspectors to be more reliable than his oral evidence. He came across as guarded and not wanting to criticise his employer. I also have some reservations about accepting parts of Mr Bunyan’s evidence.

14. Inspector Grillo prepared a technical report dated 14 September 2022 for the assistance of the Inspectors investigating the incident, which was provided to Danrae in pursuant to the prosecutor’s duty of disclosure. Inspector Grillo’s report is mainly relevant to Issue 3 but his evidence was generally consistent with the consensus of the independent experts called. No issue was taken with Inspector Grillo’s credit and I accept his evidence.

15. Mr Hunt was called as an expert witness and some issue was taken with his qualifications, rather than his credit, but it convenient to deal with that issue now. I am satisfied for the following reasons that Mr Hunt was extensively qualified to give the opinion evidence that he did. Mr Hunt was awarded a Bachelor of Engineering in Chemical Engineering from the University of Melbourne in 1964. He began work as a chemical engineer in 1965 for ICI Australia and was promoted to various positions until the company became Orica Ltd in 2000. During this time, Mr Hunt had oversight of systems for the storage and handling of dangerous chemicals and responsibility for the safety of those systems. In 2000, he commenced his own business as a consultant chemical engineer specialising in the safe storage of hazardous chemicals. As a chemical engineer, Mr Hunt acquired specialist knowledge and has undertaken specialist training about the physical and chemical properties of hazardous chemicals including flammable liquids and gases, static electricity and psychrometry (the science of the properties of gas-vapour mixtures). Mr Hunt has attended a number of conferences on static electricity and its potential as an ignition source. Mr Hunt was a fellow and past president of the Australian Institute of Dangerous Goods (AIDG) and is presently a member of two Standards Australia Committees drafting standards relating to the storage and handling of dangerous goods. Mr Hunt has been involved in devising systems for the safe storage of hazardous chemicals and investigating a number of fires caused by hazardous chemicals. I am satisfied that Mr Hunt’s evidence, most of which is not in contest, is based wholly on his specialist training and experience. Mr Hunt did make some factual assumptions on the basis of his understanding and impression of the evidence. Some of those matters were outside of his expertise and I have not relied on them in coming to my factual findings. I am satisfied that he was trying his best to give truthful and complete evidence in keeping with the Expert Code of Conduct.

Defence witness

16. Ms Jones was called as an expert witness. No issue was taken by the prosecutor with her qualifications. In my view, she was not as qualified as Mr Hunt was to express opinions based on the physical and chemical properties of the adhesive, because her training and experience on those matters was inferior to that of Mr Hunt. Contrary to the confidence expressed in her reports, Ms Jones presented as a timid witness and in her evidence she accepted that her analysis lacked supporting evidence for a number of crucial inputs. I accept that she gave evidence with regard to the Expert Code of Conduct, and that she appropriately moderated some of the opinions expressed in her reports.

Facts

17. The parties tendered an Agreed Statement of Facts which I have incorporated into my findings of fact. I will not repeat matters I have already referred to and will use the terms I have already defined. The following matters represent my findings of fact unless stated otherwise.

Background

18. Water had been leaking into the residence from the balcony at the site since the building was completed in 2018. Richard Crookes Constructions Pty Ltd (RCC) was contractually obliged to remedy the defect. The remedial work involved removing the tiles, wall cladding and balustrade from the balcony to reach the substrate, so that the membrane waterproofing could be laid. RCC arranged for the erection of a scaffold to provide access to the third floor balcony and to provide edge protection while the remedial work was being undertaken. After the waterproofing was completed, the remedial work included replacing the tiles and restoring the wall cladding and the balustrade to restore the balcony to useable condition.

19. Danrae was engaged by RCC to waterproof the balcony as part of the remedial work, which was work regularly undertaken by Danrae.

20. At the time of the incident, Mr Reid had 9 years’ experience as a water proofer and Mr Bunyan was an apprentice.

21. Danrae’s quote for completing the work for RCC was $3,906.35 plus GST. The work was expected to be completed with one day.

The incident

22. At about 7.30am on 12 November 2021 the workers arrived on site. It was raining on the day. RCC had erected a tarpaulin over the balcony to keep the work site dry. The workers accessed the balcony via the scaffold.

23. The approximate dimensions of the balcony were 2,800mm wide, 2,700mm deep and 3,200mm high. The scaffold provided an additional 1,100mm in depth to the balcony. The scaffold deck was constructed of steel scaffold planks.

24. The task involved laying Ardex Butynol Roofing and Tanking Membrane (the membrane sheets) to the floor of the balcony using the adhesive and then heat welding the sheets together where the sheets overlapped.

25. Prior to laying the membrane sheets, Mr Bunyan used the heat gun to dry areas of the balcony that were wet by the rain. After doing so he placed the heat gun on the metal deck of the scaffold, leaving it switched on although it was not in use. Mr Bunyan told Inspector Scott on the day of the incident, “The heat gun was on the whole time as drops of water were still hitting the ground, and we were drying while going”. He could not recall what setting the heat gun was on.

26. Mr Reid told the Inspectors in his recorded interview that the heat gun was two and a half to three metres away from the work area. Mr Reid gave evidence that he was unaware of what setting the heat gun had been used on to dry the water on the floor because Mr Bunyan had control of the heat gun at that time. It was ordinarily used at a setting of 6.5 out of 10 for welding the sheets, but it had not been used for that purpose prior to the fire. In his telephone interview with Inspector Scott a few days after the incident (the telephone interview), he stated:

The glue has a potent vapour. I know to keep the gun as far away as possible, but the gun and the glue are used at the same time, and the heat gun was on at the same time. I wasn’t welding at the time it happened, the gun was just on.

27. The adhesive was decanted into a plastic bucket. A paint roller was used to apply the adhesive to the back of the membrane sheets and the floor of the balcony. The sheets were then stuck to the floor after a few minutes when the adhesive had “tacked off”. The workers applied membrane sheets to the area of the balcony closest to the scaffold first, without incident.

28. Mr Reid then proceeded to apply the adhesive to the membrane sheets and the floor closest to the balcony door. Mr Reid told the Inspectors in his recorded interview that the bucket containing the adhesive was in front of him. In his evidence, Mr Reid stated that the bucket was on the balcony, but he could not recall if it was beside him or behind him. He recalled turning his body towards the bucket to put the roller back into the bucket. After Mr Reid placed the roller back into the bucket he heard a “woof” noise of the adhesive igniting and he saw flames around his legs. Mr Reid could not recall seeing where the fire first occurred. In his recorded interview, Mr Reid stated on a number of occasions that the fire started behind him. In his evidence, he stated that he may have reconstructed that evidence. His best recollection was that he first heard the sound of the ignition, did not observe where the flames came from, and that the ignition occurred very quickly.

29. At the time of the incident, Mr Reid was wearing a shirt, a football jersey, shorts, steel-capped boots and eye protection glasses. Mr Reid knew that the required PPE was specified in the SDS and he had been provided with the requisite PPE by Danrae. He told Inspector Scott in the telephone interview that he had not been trained by Danrae what to wear and there was no direct rule on what to wear.

30. Mr Reid used his jacket to extinguish the fire before leaving the balcony. The bucket was “flicked off” the balcony in the incident landing in the garden below, with the adhesive on fire in it, which melted the bucket.

31. Mr Reid and Mr Bunyan left the balcony via the scaffold and used a bubbler at the park next door to apply water to Mr Reid’s legs. Mr Bunyan returned to the balcony to turn off the heat gun and when he did so he noticed that the roller was still on fire.

32. At approximately 9:02am, Mr Bunyan called emergency services. Mr Reid was conveyed by ambulance to Royal North Shore Hospital for treatment. He was discharged on the same day. He required further treatment at the Burns Unit as an outpatient.

33. Fire and Rescue NSW attended the scene and inspected the balcony to ensure that the site was safe.

34. Photos were taken by Fire and Rescue NSW and Inspector Scott after the incident. Mr Reid gave evidence that some of the items on the balcony had been moved and were not in the location that they had been when the fire ignited. I have not relied on the photographs to depict where items were placed at the time of the incident.

Systems of work in place prior to the incident

35. Danrae had in force a SWMS for the activities of “Waterproofing of Rooftops, Balconies & Wet Areas”. It contained a warning to “keep ignition sources away from the waterproofing area”. It did not identify the heat gun as a potential ignition source.

36. No SWMS was prepared for the particular job at the site, and the workers were not required to go through the SWMS or adopt it for the purpose of the work at the site. Mr Luce did not believe that a SWMS for the work at the site was necessary.

37. Danrae used a mobile phone application known as “SimPRO” (the SimPRO app). The SimPRO app required workers to answer questions prior to being able to log their start time which was necessary to record the time that they worked on a job. The SimPRO app was intended to be a short form risk assessment conducted by the workers for the job they were about to undertake.

38. Mr Caruana described the process of completing the SimPRO app as a “take 5 checklist” that workers had to complete before they could log their time for a particular job. In evidence, Mr Caruana sought to describe the SimPRO app process at a high level of generality and implying that it required consideration of a number of specific topics. His evidence was inconsistent with the abstruse documents Danrae provided to SafeWork in the course of the investigation. Mr Caruana gave evidence that each “prompt” required an answer, which was contrary to the agreed facts that the SimPRO app allowed workers to skip screens, a deficiency that was remedied after the incident. I do not accept Mr Caruana’s evidence on the content of the SimPRO app. In any event, for reasons I will come to, it did not provide the workers with the requisite information and it did not constitute an adequate risk assessment.

35. Mr Reid did not use the SimPRO app on the day of the incident before commencing the work at the site. Mr Reid told Inspector Scott in the telephone interview that the SDSs for chemicals used in his waterproofing tasks were uploaded to the system, but that he did not feel that he needed to look at the SDS for the adhesive because he knew that it, was “toxic, there are potent fumes, you want to wear a mostly non-flammable clothes, not have a naked flame near it”.

36. Danrae had the Operators Manual for the heat gun but it was not available to the workers at the site and the workers had not been required to review it. Mr Reid had been trained on how to use the heat gun.

37. The heat gun had not been tested and tagged as being compliant with Australian Standard 3760:2010 In-service safety inspection and testing of electrical equipment and RCDs (AS 3760).

38. Mr Reid had a Certificate III in Waterproofing and had completed the Ardex WPM1000 Training Accreditation provided by Ardex in April 2017 (the Ardex training course).

39. Mr Bunyan had completed a Certificate III in Waterproofing but had not attended the Ardex training course. Mr Bunyan was not familiar with the SWMS and could not recall being asked to sign it. Mr Bunyan told the Inspectors in his recorded interview that he did not have a detailed understanding of how to perform the work on the day of the incident because he was still learning. He had a basic idea of how to perform the work from his TAFE course. He understood that he was present to watch Mr Reid and to learn from him.

40. Mr Caruana completed the Ardex training course in about 2018.

41. The Ardex training course handouts were in evidence and contained the following two pages of which most of the text appeared in bold red type for emphasis:

46. Mr Luce gave evidence that he conducted “spot checks” to see if workers were wearing the correct PPE on bigger jobs, which he stated were jobs that went for more than one day. He did not attend smaller jobs, such as the one where the incident occurred.

47. Mr Reid told the Inspectors in his recorded interview that he had seen the SDS for the adhesive, but he had not sat down and read it “page to page”.

Relevant guidance material

48. The following guidance material was readily available to Danrae prior to the incident.

49. SafeWork NSW, Managing the Risk of Hazardous Chemicals - Code of Practice (the Hazardous Chemicals Code), published in August 2019, and its previous version published in 2014, provided guidance on how to manage risks associated with hazardous chemicals in the workplace using a systematic process of identification, risk assessment, elimination, or otherwise risk control and risk review. It also outlines managing the risks of fire and explosion.

50. Australian Standard 60079.10.1 Classification of Hazardous Areas provided guidance around classifying environments where explosive gas atmospheres may occur to develop suitable controls to ensure that equipment can be used safely in that environment, and in particular that sources of ignition are not introduced.

51. The Operators Manual for the Leister Triac-ST heat gun (Heat Gun) advised that “incorrect use of the heat gun…can present a fire and explosion hazard, especially near…explosive gases”.

52. The SDS of the adhesive dated 17 September 2020 contained the following information:

Hazard Classification:
Flammable Liquids – Category 2

Hazard statements:
H225 - Highly flammable liquid and vapour

Prevention Precautionary Statements
P201 – Obtain special instructions before use
P210 – Keep away from heat/sparks/open flames/hot surfaces...
P241 – Use explosion-proof electrical, ventilating, lighting and all other
P271 - Use only outdoors or in a well-ventilated area

Special hazards: Hazard Classification:
Flammable Liquids – Category 2

Special hazards:
Liquid and vapour are highly flammable.
Severe fire hazard when exposed to heat, flame and/or oxidisers.
Vapour may travel a considerable distance to source of ignition.
Heating may cause expansion or decomposition leading to violent rupture of containers.

Fire fighting further advice:
Heating can cause expansion or decomposition leading to violent rupture of containers…

53. The SDS provided that the following protective clothing was required for the safe handling of the adhesive:

1. safety glasses with side shields;

2. chemical protective gloves;

3. safety footwear;

4. overalls; and

5. PVC Apron.

54. The container of the adhesive was labelled

GIVES OFF HIGHLY FLAMMABLE VAPOUR / Keep well away from heat, sparks and open flame / keep closed when not in use.

Post incident conduct

55. Inspector Scott issued a prohibition notice and a number of improvement notices to Danrae relating to the incident.

56. In response to the notices, Danrae:

1. Developed the Hazards Associated with Ardex WA 98 Course on the Go1 training platform, providing training to workers on the nature of work, risks associated, and control measures to be implemented when using the adhesive and a plain English safety data sheet for the adhesive, highlighting that it is highly flammable in liquid and vapour form.

2. Updated the pre-start checklist on the SimPRO app to ensure that employees could not skip screens and made the information from the SDS available in the app.

3. Developed a SWMS for the activity of “Using Ardex WA98 in the Proximity of the Leister Welder” and trained its workers on it.

4. Developed a Safe Operating Procedure for applying the adhesive.

5. Prohibited the use of the adhesive in confined areas.

The expert evidence

57. The experts called by the parties ultimately agreed on most of the issues between them. They both gave evidence that the fire was caused by the ignition of the solvents in the adhesive and that the heat gun was the most probable ignition source.

58. There remained minor disagreement on whether there was a reasonable possibility that static electricity was the ignition source of the fire. Ms Jones contended that it remained possible, whereas Mr Hunt’s evidence was that it was a possibility of last resort that could be excluded because it was many times more likely that the heat gun was the ignition source. I will resolve that controversy when dealing with Issue 3.

59. At this point it is convenient to set out what the experts agreed on in so far as that was relevant to the cause of the fire.

60. The SDS for the adhesive specified that it had a flashpoint of -15^oC, which is very low, making it a highly flammable substance.

61. The SDS also specified that the adhesive had an Upper Explosive Limit (UEL) of 7% and a Lower Explosive Limit (LEL) of 1%. This meant that the vapour given off by the adhesive would ignite when it was present in a concentration of between 1% and 7% (the flammable range).

62. The SDS provided that the vapour was a mixture of the solvents being acetone, toluene and hexanes, each of which are highly flammable.

63. When the adhesive was in the container or had been decanted into the bucket, Mr Hunt calculated that the concentration of the vapour immediately above the adhesive liquid was about 24%, which was too high for the vapour to ignite.

64. When the adhesive was decanted into the bucket and rolled onto the membrane sheets and the floor, the solvents in the vapour evaporated causing the concentration of the vapour to decrease and making it possible for the vapour to reach the flammable range of a concentration of between 1% and 7%, at which time it could ignite if an ignition source was present.

65. The vapour was heavier than air and the motions of decanting the adhesive, dipping the roller in the bucket and using the roller to apply the adhesive to surfaces, caused the vapour to disburse at floor level.

66. The concentration of the vapour was more likely to reach the flammable range the further it travelled away from the bucket.

67. As a matter of scientific certainty, the concentration of the vapour reached the flammable range to permit it to ignite and to cause the fire.

68. The solvents would auto ignite at temperatures of 234^oC for hexanes, 465^oC for acetone and 480^oC for toluene.

69. The Operator Manual for the heat gun specified that the air discharged by the heat gun would exceed the auto ignition temperature for hexanes at between settings 2 and 3 and the auto ignition temperatures for acetone and toluene at about setting 6 and above.

The Relevant Law

70. Section 12A of the Act provides:

Strict liability applies to each physical element of each offence under this Act unless otherwise stated in the section containing the offence.

71. A duty provided for by the Act is not transferable and a person can have more than one duty: ss 14 and 15 of the Act.

72. Section 17 of the Act provides:

A duty imposed on a person to ensure health and safety requires the person--

(a)   to eliminate risks to health and safety, so far as is reasonably practicable, and

(b)   if it is not reasonably practicable to eliminate risks to health and safety, to minimise those risks so far as is reasonably practicable.

The s 19(1) duty – duty of a PCBU to ensure the health and safety of workers

73. The content of the duty is set out in s 19 of the Act, which relevantly provides:

(1)   A person conducting a business or undertaking must ensure, so far as is reasonably practicable, the health and safety of:

(a)   workers engaged, or caused to be engaged by the person, and

(b)   workers whose activities in carrying out work are influenced or directed by the person,

while the workers are at work in the business or undertaking.

…

(3)   Without limiting subsections (1) and (2), a person conducting a business or undertaking must ensure, so far as is reasonably practicable:

(a)   the provision and maintenance of a work environment without risks to health and safety, and

(b)   the provision of safe plant and structures, and

(c)   the provision and maintenance of safe systems of work, and

(d)   the safe use, handling and storage of plant, structures and substances, and

…

(f)   the provision of any information, training, instruction or supervision that is necessary to protect all persons from risks to their health and safety arising from work carried out as part of the conduct of the business or undertaking, and

(g)   that the health of workers and the conditions at the workplace are monitored for the purpose of preventing illness or injury of workers arising from the conduct of the business or undertaking.

74. The requirement to “ensure” means to guarantee or make certain: Carrington Slipways Pty Ltd v Callaghan (1985) 11 IR 467 at 470.

75. Safety cannot be ensured if a risk to the health and safety of a worker exists. The existence of the risk constitutes a breach of s 19 of the Act. It is not necessary that there is an accident or that a person is injured: Kirk v Industrial Court of New South Wales (2010) 239 CLR 531 at [13]. The relevant risk for the commission of the s 32 offence is the risk of death or serious injury.

76. The word “risk” is not defined in the Act. Risk means the mere possibility of danger and not necessarily actual danger: R v Board of Trustees of the Science Museum [1993] 1 WLR 1171 and Thiess Pty Ltd v Industrial Court of New South Wales (2010) 78 NSWLR 94 at [67].

77. An incident causing injury may be evidence of the presence of a risk and may be relevant to sentencing as a measure of the severity of the harm suffered as a result of the risk. But a distinction must be drawn between the specific risk that manifested in the incident and the general class of risk that the analysis must focus on. Paying too close attention to the specific risk resulting in an incident can lead to error: Tangerine Confectionery Ltd and Veolia ES (UK) Ltd v R [2011] EWCA Crim 2015 and Director of Public Prosecutions v Vibro-Pile (Aust) Pty Ltd (2016) 49 VR 676 at [3]-[6].

78. A duty imposed to ensure health and safety requires the person to eliminate risks to health and safety so far as that is reasonably practicable, and if that cannot be done, to minimise those risks so far as is reasonably practicable: s 17 of the Act. The risk should be identified with sufficient precision to determine if it was reasonably practicable to eliminate it or minimise it.

79. “Reasonably practicable” is defined in s 18 of the Act. The court must take into account and weigh up all relevant matters including;

1. the likelihood of the risk concerned occurring, and

2. the degree of harm that might result from the risk, and

3. what the defendant knows or ought reasonably to know about;

4. the risk, and

5. ways of eliminating or minimising the risk, and

6. the availability and suitability of ways to eliminate or minimise the risk, and

7. after assessing the extent of the risk and the available ways of eliminating or minimising the risk, the cost associated with either of those options, including whether the cost is grossly disproportionate to the risk.

80. The state of knowledge applied to the definition of practicable is objective. It is that possessed by persons generally who are engaged in the relevant field of activity and should not be assessed by reference to the actual knowledge of a specific defendant in particular circumstances: Laing O’Rourke (BMC) Pty Ltd v Kirwin [2011] WASCA 117 at [33].

81. The reasonably practicable requirement applies to matters which are within the power of the defendant to control, supervise and manage: Slivak v Lurgi (Aust) Pty Ltd (2001) 205 CLR 304 at [37] (Gleeson CJ, Gummow and Hayne JJ).

82. The phrase “exposed to risks” contained in s 8(2) Occupational Health and Safety Act 2000 has been interpreted to mean that a person was sufficiently proximate to the source of a risk for the risk to come home, irrespective of the mechanism by which that could happen: Thiess.

83. The s 19 duty requires knowledge of the risk emanating from the activities of the defendant: Slivak. Foreseeability of the risk to persons from the activity is an element of this question of knowledge. It would not generally be practicable to take measures to guard against a risk to safety that was not reasonably foreseeable: Genner Constructions Pty Ltd v WorkCover Authority of New South Wales [2001] NSWIRComm 267 at [68].

84. The statutory duty is not limited to simply preventing foreseeable risks of injury. The duty is to protect against all risks, if that is reasonably practicable. Reasonably practicable means something narrower than physically possible or feasible: Slivak at [53] (Gaudron J).

85. The words “reasonably practicable” indicate that the duty does not require a duty holder to take every possible step that could be taken. The steps to be taken in performance of the duty are those that are reasonably practicable for the duty holder to achieve the provision and maintenance of a safe working environment. Bare demonstration that a step might have had some effect on the safety of a working environment does not, without more, demonstrate a breach of the duty: Baiada Poultry Pty Ltd v R (2012) 246 CLR 92 at [15], [33] and [38] (French CJ, Gummow, Hayne and Crennan JJ).

86. A duty holder must have a proactive approach to safety issues. The question is not did the duty holder envisage a particular danger, but rather should it have: WorkCover Authority of New South Wales v Kellogg (Aust) Pty Ltd [1999] NSWIRComm 453.

87. A duty holder must have a structured and systematic approach to risk management: WorkCover Authority of NSW v Atco Controls Pty Ltd (1998) 82 IR 80 at 85 (Hill J) and Inspector Ching v Bros Bins Systems Pty Ltd [2004] NSWIRComm 197 at [32].

88. A duty holder must have regard not only for the ideal worker but also for one who is careless, inattentive or inadvertent: Dunlop Rubber Australia Ltd v Buckley (1952) 87 CLR 313 at 320 (Dixon CJ). If there is a foreseeable risk of injury arising from a worker’s negligence in carrying out his or her duties then this is a factor which the duty holder must take into account: Smith v Broken Hill Pty Ltd (1957) 97 CLR 337 at 343. It may not always be possible to foresee various acts of inadvertence by workers but duty holders must conduct operations on the basis that such acts will occur and they must be guarded against to the fullest extent practicable.

89. The unforeseeable behaviour of a disobedient worker may well lead to the happening of an event that could not be reasonably foreseen and therefore was not reasonably practicable to guard against: WorkCover Authority of New South Wales v Kirk Group Holdings Pty Ltd (2004) 135 IR 166 at [129].

90. One of the matters PCBUs must recognise and plan for is the inevitability of human error ranging from inadvertence, inattention or haste through to foolish disregard of personal safety and deliberate non-compliance with safe systems of work: R v Commercial Industrial Construction Group Pty Ltd (2006) 14 VR 321 at [49] and Director of Public Prosecutions v JCS Fabrications Pty Ltd and JMAL Group Pty Ltd [2019] VSCA 50 at [51].

91. Where an employer is found to have laid down a safe and proper practice and there is no evidence that the employer failed to use due diligence to see that the practice was observed, then a casual failure by inferior employees, even if of supervisory rank, to observe that practice on a particular occasion will not render the employer criminally liable for a failure to ensure safety: Collins v State Rail Authority of New South Wales (1986) 5 NSWLR 209 at 215E.

92. The question of what is reasonably practicable is also a question of fact, determined by the circumstances of each case. The fact that a worker has carried out work carelessly or omitted to take a precaution does not preclude the duty holder from establishing that everything that was reasonably practicable in their undertaking to ensure that persons were not exposed to risks to their health and safety had been done: R v Nelson Group Services (Maintenance) Ltd [1998] 4 All ER 332 at 351e-f.

93. Section 275 of the Act provides that an approved code of practice is admissible in proceedings for an offence against the Act as evidence of whether a duty under the Act has been complied with. The court may have regard to the code as evidence of what was known about a risk or the measures available to control the risk and may rely on the code to determine what is reasonably practicable in the circumstances to which the code relates. Clause 3 of Schedule 4 of the Act provides that an industry code of practice approved and enforced under Part 4 of the Occupational Health and Safety Act 2000 immediately before the repeal of that Act is taken to be an approved code of practice under Part 14 of the Act.

94. Part 3.1 of the Regulations (clauses 32-38) applies to a PCBU who has a duty under the Regulations to manage risks to health and safety. Clause 34 requires a duty holder to identify foreseeable hazards that could give rise to risks to health and safety. Clause 35 of the Regulations requires a duty holder to eliminate risks to health and safety so far as is reasonably practicable and if it is not reasonably practicable to eliminate risks to minimise those risks so far as is reasonably practicable. Clause 36 of the Regulations sets out the hierarchy of control measures to be implemented to minimise risk as: substitution; isolation; engineering controls; administrative controls and provision of personal protective equipment (PPE). Clause 37 of the Regulations requires a duty holder who implements control measures to ensure they are maintained, fit for purpose, suitable for the nature and duration of the work and installed, set up and used correctly. Clause 38 of the Regulations requires a duty holder to revise its control measures to maintain, so far as is reasonably practicable, a work environment that is without risk to health or safety.

95. Clause 289 of the Regulations provides:

289 Meaning of “construction work”

(1)   In this Chapter,

“construction work” means any work carried out in connection with the construction, alteration, conversion, fitting-out, commissioning, renovation, repair, maintenance, refurbishment, demolition, decommissioning or dismantling of a structure.

(2)   Without limiting subclause (1),

“construction work” includes the following--

(a)   any installation or testing carried out in connection with an activity referred to in subclause (1),

(b)   the removal from the workplace of any product or waste resulting from demolition,

(c)   the prefabrication or testing of elements, at a place specifically established for the construction work, for use in construction work,

(d)   the assembly of prefabricated elements to form a structure, or the disassembly of prefabricated elements forming part of a structure,

(e)   the installation, testing or maintenance of an essential service in relation to a structure,

(f)   any work connected with an excavation,

(g)   any work connected with any preparatory work or site preparation (including landscaping as part of site preparation) carried out in connection with an activity referred to in subclause (1),

(h)   an activity referred to in subclause (1), that is carried out on, under or near water, including work on buoys and obstructions to navigation.

(3)   In this Chapter,

“construction work” does not include any of the following--

(a)   the manufacture of plant,

(b)   the prefabrication of elements, other than at a place specifically established for the construction work, for use in construction work,

(c)   the construction or assembly of a structure that once constructed or assembled is intended to be transported to another place,

(d)   testing, maintenance or repair work of a minor nature carried out in connection with a structure,

(e)   mining activities or petroleum activities.

96. Clause 291(l) of the Regulations defines “high risk construction work” as including construction work that “is carried out in an area that may have a contaminated or flammable atmosphere”. This triggers the application of clause 299(2) of the Regulations, which requires a person carrying out high risk construction work to prepare a SWMS that must:

(a)    identify the work that is high risk construction work, and

(b)    specify hazards relating to the high risk construction work and risks to health and safety associated with those hazards, and

(c)    describe the measures to be implemented to control the risks, and

(d)    describe how the control measures are to be implemented, monitored and reviewed.

97. Clause 9 of the Regulations provides:

If a note at the foot of a provision of this Regulation states “WHS Act” followed by a reference to a section number, the clause provision sets out the way in which a person’s duty or obligation under that section of the Act is to be performed in relation to the matters and to the extent set out in the clause provision.

Note : A failure to comply with a duty or obligation under a section of the Act referred to in a “WHS Act” note is an offence to which a penalty applies.

98. Clause 51 of the Regulations provides:

(1)   A person conducting a business or undertaking at a workplace must manage risks to health and safety associated with a hazardous atmosphere at the workplace, in accordance with Part 3.1.

Note : WHS Act--section 19 (see clause 9).

(2)   An atmosphere is a hazardous atmosphere if--

(a)   the atmosphere does not have a safe oxygen level, or

(b)   the concentration of oxygen in the atmosphere increases the fire risk, or

(c)   the concentration of flammable gas, vapour, mist or fumes exceeds 5% of the LEL for the gas, vapour, mist or fumes, or

(d)   combustible dust is present in a quantity and form that would result in a hazardous area.

99. Clause 52 of the Regulations provides:

(1)   A person conducting a business or undertaking at a workplace must manage risks to health and safety associated with an ignition source in a hazardous atmosphere at the workplace, in accordance with Part 3.1.

Note : WHS Act--section 19 (see clause 9).

(2)   This clause does not apply if the ignition source is part of a deliberate process or activity at the workplace.

100. Clause 351 of the Regulations provides:

(1)   A person conducting a business or undertaking must manage, in accordance with Part 3.1, risks to health and safety associated with using, handling, generating or storing a hazardous chemical at a workplace.

Note : WHS Act--section 19 (see clause 9).

(2)   In managing risks the person must have regard to the following--

(a)   the hazardous properties of the hazardous chemical,

(b)   any potentially hazardous chemical or physical reaction between the hazardous chemical and another substance or mixture, including a substance that may be generated by the reaction,

(c)   the nature of the work to be carried out with the hazardous chemical,

(d)   any structure, plant or system of work--

(i)   that is used in the use, handling, generation or storage of the hazardous chemical, or

(ii)   that could interact with the hazardous chemical at the workplace.

101. Clause 355 of the Regulations provides:

A person conducting a business or undertaking at a workplace must, if there is a possibility of fire or explosion in a hazardous area being caused by an ignition source being introduced into the area, ensure that the ignition source is not introduced into the area (from outside or within the space).

: Maximum penalty--

(a)   in the case of an individual--70 penalty units, or

(b)   in the case of a body corporate--345 penalty units.

102. Post-incident conduct is some evidence that the steps taken were reasonably practicable. However, when it comes to the application of s 18 of the Act, that evidence may not be determinative of the issue. The court must be satisfied beyond reasonable doubt that the steps were reasonably practicable to achieve the provision of a safe working environment prior to the incident and not with the benefit of hindsight: Davis v Langdon [1911] 11 SR (NSW) 149; Nelson v John Lysaght (Australian Ltd) (1975) 132 CLR 201 at 215 (Gibbs J, Steven and Mason JJ agreeing), Saunders Civilbuild Pty Ltd v SafeWork NSW [2023] NSWCCA 261 at [268] and SafeWork NSW v Tamex Transport Services Pty Ltd [2016] NSWDC 295 at [76].

103. Section 244 of the Act provides:

(1)   For the purposes of this Act, any conduct engaged in on behalf of a body corporate by an employee, agent or officer of the body corporate acting within the actual or apparent scope of his or her employment, or within his or her actual or apparent authority, is conduct also engaged in by the body corporate.

(2)   If an offence under this Act requires proof of knowledge, intention or recklessness, it is sufficient in proceedings against a body corporate for that offence to prove that the person referred to in subsection (1) had the relevant knowledge, intention or recklessness.

(3)   If for an offence against this Act mistake of fact is relevant to determining liability, it is sufficient in proceedings against a body corporate for that offence if the person referred to in subsection (1) made that mistake of fact.

Causation

104. The relevant question on causation is whether the act or omission of the defendant was a significant or substantial cause of the worker being exposed to the risk of injury: Bulga Underground Operations v Nash [2016] NSWCCA 37 at [127].

105. The question is to be determined by the application of common sense to the facts, bearing in mind that the purpose of the inquiry is to attribute legal responsibility in a criminal matter: Royall v The Queen (1991) 172 CLR 378.

106. Regard must be had to the scope and objects of the Act: Simpson Design and Associates Pty Ltd v Industrial Court of New South Wales [2011] NSWCA 316 at [79]-[102]. The relevant question is not whether the particularised failures of the defendant were the cause of the injury to the worker, but rather whether there was a causal relationship between the act or omission and the risk to which the worker was exposed: Bulga Underground at [130].

107. A finding of causation requires a backward-looking analysis of what actually occurred in order to attribute liability for a criminal offence: Grasso Consulting Engineers Pty Ltd v SafeWork NSW [2021] NSWCCA 288 at [226] (Cavanagh J).

consideration

Issue 1   Did the defendant fail to comply with its health and safety duty by failing to take the steps particularised in [10] of the Summons? (Element 2)

108. The prosecutor is required to demonstrate the particular measures that should have been taken to prevent the risk identified: Kirk at [37].

109. In order to find Element 2 established, I must be satisfied beyond reasonable doubt that the defendant failed to comply with its health and safety duty by failing to take the steps set out in the particulars of breach in [10] of the Summons and that the steps were reasonably practicable.

110. I will now deal with the common matters that are of relevance to the issue of whether the pleaded measures in [10] of the Summons were reasonably practicable.

The pleaded risk

111. The pleaded risk was the risk of workers suffering death or serious injury from fire and/or explosion when using hazardous chemicals in the vicinity of an ignition source.

112. Danrae submitted that the evidence of the injury sustained by Mr Reid demonstrated that the risk was a risk of serious injury only and there was no proper basis to find there was a risk of death. I do not accept that submission because it focuses too narrowly on the specific incident and it is contrary to the authorities set out at [77] above. It was reasonably foreseeable that a flash fire or explosion could have resulted in much more serious consequences compared to what actually occurred and that included the death or one or both of the workers and this was recognised in the pre-incident SWMS.

The likelihood of the risk occurring

113. The likelihood of the risk occurring was high. The vapour given off by the adhesive was highly flammable and the introduction of an ignition source brought with it a serious risk of a fire or explosion.

The degree of harm

114. The degree of harm that might eventuate if a person was in close proximity to a fire or explosion, included a risk of death.

The defendant’s knowledge of the risk

115. The risk posed by the use of the highly flammable adhesive in the vicinity of an ignition source was known to Danrae. It was referred to in the SWMS in force at the time of the incident. Mr Reid and Mr Caruana had completed the Ardex training course and knew that a heat gun was a potential ignition source. Danrae also had access to the label on the adhesive and the SDS that warned that the vapour given off by the adhesive was highly flammable and that it could travel long distances. Mr Reid and Mr Caruana were trained on the content of the SDS in the Ardex training course.

The defendant’s knowledge of the ways of eliminating or minimising the risk

116. Danrae knew that it was necessary to train its workers as to the risks posed by using the adhesive, which included a risk of fire or explosion if an ignition source was introduced to the area where the adhesive was being used.

117. Danrae had specified in the SWMS in force at the time of the incident that ignition sources were not to be introduced into the area where the adhesive was being used.

118. Danrae knew that essential safety information for the adhesive was contained in the SDS.

119. Danrae knew from the Ardex training course that the heat gun was a potential ignition source for the vapour.

120. Danrae knew that a heat gun was an approved item of plant that workers ordinarily had with them to weld the membrane sheets together as an essential aspect of this kind of waterproofing work.

Cost of the particularised measures

121. It was not contended that the cost of any of the particularised measures set out in [10] in the Summons was grossly disproportionate to the risk. The evidence was that the remedial measures were introduced within a very short time after the incident in response to the incident.

Post incident steps

122. Danrae contended that the Court could not have regard to the post-incident steps taken by it because they were introduced under compulsion in response to the prohibition and improvement notices. I reject that submission. Whilst the post-incident steps were introduced after the issue of the notices and Danrae was compelled to comply with those notices, Danrae was free to take whatever steps it thought appropriate to comply with the notices and discharge its s 19(1) duty. There is no evidence that it was compelled by the Regulator to take the particular steps that it did.

123. In considering the steps taken by Danrae post-incident, I have applied the principles set out at [102] above.

Reasonably practical steps

124. I will now turn to consider the pleaded particulars of breach of duty.

Failing to conduct an adequate risk assessment [1]

1. [10](f) of the Summons.

125. It is convenient to deal with this particular first, because the conduct of an adequate risk assessment was an indispensable starting point to assessing the risks posed by the adhesive and identifying appropriate control measures to eliminate or minimise the risk.

126. Part 3.1 of the Regulations obliged Danrae to conduct a systematic risk assessment in accordance with cls 34-38. Clauses 51, 52, 351 and 355 obliged Danrae to also assess the risks involved with the use of hazardous chemicals and ignition sources.

127. There was no evidence that Danrae had conducted a risk assessment for the adhesive prior to the incident.

128. In formulating the SWMS that was in force at the time of the incident, it can be accepted that Danrae undertook some form of risk assessment. The question is whether or not the risk assessment was adequate.

129. The Hazardous Chemicals Code provides [2] that a basic risk assessment consists of:

• Reviewing the labels and SDS of the hazardous chemicals and assessing the risks involved in their use, and

• Deciding whether the hazardous chemicals in the workplace are already controlled with existing control measures, as recommended in the SDS or other reliable sources, or whether further control measures are needed.

  2. In section [3.2] at page 22.

130. The pre-incident SWMS did not make any express mention of the use of the adhesive by name, or that it was a highly flammable substance. In section 4 under the heading “Work area set-up”, the SWMS identified a risk of “Fire/explosion” with an assigned risk rating of 4A – the highest risk rating, and the corresponding action “DO NOT PROCEED”. The control measure to be implemented to reduce the risk rating to “Moderate” [3] was stated as:

• Keep ignition sources away from the waterproofing area as there could be danger of fire or explosion from ignited fumes.
  

  3. Expressed to be capable of being controlled through the implementation of control measures.

  Note: Ignition sources include, pilot lights, stoves, heaters, cigarettes, matches/lighters, griding, welding, power points, lighting, light switches, radio transmitters, mobile phones, battery powered forklifts etc.

131. In section 9 under the heading “Using power tools”, the SWMS identified a risk of “Fire/explosion” with an assigned risk rating of 3H – the second highest risk rating, and the corresponding action “Review before commencing work”. The control measure to be implemented to reduce the risk rating to moderate was stated as:

• Do not operate power tools in explosive atmosphere (ie presence of flammable liquids, gases or dust).

132. In section 7 under the heading “Torch-on/PVC sheet membranes”, the SWMS identified the risk of “contact with hazardous chemical substances”, with an assigned risk rating of 3H – the second highest risk rating, and the corresponding action “Review before commencing work”. The control measure to be implemented to reduce the risk rating to moderate was stated as:

• Ensure SDS for the membrane and gas is available.

• Ensure PPE as per SDS is worn.

• Training and experience is recommended to ensure the integrity of the membrane.

133. A “Hot Air Welding Gun” was specified by the SWMS to be a standard tool to be used for the task of waterproofing rooftops balconies and wet areas. It was not in dispute that a hot air welding gun was the same piece of equipment as a heat gun. There was no mention in the SWMS of a heat gun being a potential ignition source.

134. Clause 51 of the Regulations required Danrae to assess the risks to health and safety associated with a hazardous atmosphere which exists if, relevantly, the concentration of a vapour exceeds 5% of the LEL for that vapour. In the present case, the evidence demonstrates that the initial concentration of the vapour was 24% which decreased over time as the solvents in the vapour evaporated. The LEL was stated in the SDS to be 1%, and the concentration of the vapour clearly exceeded 5% of the LEL being 0.05% (ie 5% of the LEL of 1%).

135. Clause 52 of the Regulations required Danrae to assess the risks to health and safety associated with an ignition source in a hazardous atmosphere at a workplace.

136. Clause 351 of the Regulations required Danrae to assess the “hazardous properties” of the hazardous chemicals it was using and to consider if the use of any plant that could interact with the hazardous chemical at a workplace. “Plant” was defined in s 4 of the Act, to include a tool and clearly included the heat gun. The Hazardous Chemicals Code provided guidance that a basic risk assessment for a hazardous chemical would involve a consideration of the SDS for that chemical.

137. Clause 355 of the Regulations required Danrae to assess the risk of a fire or explosion caused by the introduction of an ignition source into a hazardous area. Danrae knew from the Ardex training course that the heat gun was an ignition source but had not included that relevant warning in the SWMS.

138. The extent to which Danrae failed to comply with the obligations imposed by the Regulations, is relevant to whether or not it breached its s 19 duty: cl 9 of the Regulations.

139. The SWMS did not make any specific reference to the adhesive or the content of its SDS. There was no evidence in the SWMS that Danrae assessed the risks posed by the adhesive that were referred to in the SDS and that could be encountered by the workers when using it. Rather, it directed the workers consult the relevant SDS for any chemical that they could be required to work with, without providing any specific guidance on how to safely use any particular chemical.

140. The SWMS did not state that the adhesive in liquid and vapour form was highly flammable, that the vapour could travel long distances to an ignition source or set out the required PPE to be worn when using the adhesive.

141. Danrae knew that a heat gun was an approved tool to weld the membrane sheets together after they had been laid, and it was likely that a heat gun would be used by the workers at some stage of the process. The SWMS failed to identify the heat gun as a potential ignition source, notwithstanding that Danrae knew from the Ardex training course that a heat gun was considered to be an ignition source.

142. The SWMS did not identify as an essential control measure a direction that the heat gun was not to be used or turned on in the area where the adhesive was being used.

143. As a further matter, Mr Reid did not conduct any risk assessment on the day of the incident to consider if the environment of the area where the work was to be undertaken presented any specific risks. Danrae had in place a system requiring Mr Reid to enter certain information into the SimPRO app to assess some risks referred to in the app before commencing the work. He did not do so on the day of the incident because he was running late to work. The requirement of the workers to complete the SimPRO app was not effectively enforced. Mr Luce had an ad hoc system of “spot checks” but it was not systematic and was only carried out on bigger jobs. Even if Mr Reid had completed the risk assessment inherent in entering the required information into the SimPRO app, for the reasons given, it was not sufficient to constitute an adequate risk assessment.

144. The conduct of an adequate risk assessment was a task that Danrae was legally obliged to undertake. An adequate risk assessment could have been conducted at minimal cost and with very little inconvenience to Danrae’s business. I am satisfied that the cost of conducting an adequate risk assessment was not grossly disproportionate to the risk.

133. I am satisfied beyond reasonable doubt that Danrae breached its s 19(1) duty by failing to take the reasonably practicable step pleaded in [10](f) of the Summons.

Failing to provide a SWMS for the task that considered the SDS [4] and confirming that the SDS was understood by the workers [5]

4. [10](a) of the Summons.

5. [10](b) of the Summons.

146. These particulars can be conveniently dealt with together.

147. The prosecutor contended that Danrae should have devised and implemented a SWMS or written safe work procedure (SWP) for using the adhesive that considered the SDS, required adequate ventilation and required the use of appropriate PPE. The prosecutor also contended that Danrae should have provided the SDS to the workers and confirmed that they understood it contents. One way of achieving the latter was to incorporate the essential information from the SDS into the SWMS or SWP, to train the workers on the SWMS or SWP and to have them sign it as an acknowledgement that they understood the training conveyed in those documents.

148. The prosecutor’s primary argument on this point was that the work was “high risk construction work” within the meaning of cl 291 of the Regulations and that by operation of cl 299 Danrae was obliged to have a SWMS in force for the work. Danrae contended that the work was not high risk construction work by reference to the examples provided for in the guidance material and/or it was “repair work of a minor nature carried out in connection with a structure” and thereby excluded from the definition of “construction work” in cl 289.

149. The SafeWork NSW Code of Practice Construction Work 2019 (the Construction Code) provided the following examples of high risk construction work that was work carried out in an area that may have a contaminated or flammable atmosphere:

• removing pipework or tank that may contain the residue of hazardous chemicals

• demolishing a petrol station and removing old tanks

• decommissioning plant.

150. I am satisfied that the work being conducted at the site was high risk construction work because it was carried out in an area where there may have a flammable atmosphere for the reasons that follow. First, the incident demonstrated that there was a flammable atmosphere in the work area. The physical properties of the vapour being heavier than air caused it to disperse at floor level across the balcony. At that level the balcony was enclosed on three sides, by the side walls and the entry door to the residence, meaning that the vapour could only escape by moving towards the scaffold. This caused a build- up of flammable vapours on the surface of the balcony floor that could be ignited if exposed to a source of ignition. The ignition of the vapour resulting in the flash fire was incontrovertible evidence of the existence of a flammable atmosphere. Second, Danrae had recognised in the SWMS that there was the risk of a fire or explosion from the fumes of chemicals used in waterproofing tasks and it knew from the SDS for the adhesive and the Ardex training course, that a work area may have a flammable atmosphere. Third, the work created a hazardous atmosphere within the meaning of cl 51 of the Regulations. Fourth, the examples given in the Construction Code can be used as an aid to understanding the meaning of the Regulations, but they are not a substitute for the language considered in context and should not be relied on to displace the meaning of the text.

151. The Construction Code provided the following examples of and commentary on the phrase “repair work of a minor nature carried out in connection with a structure”:

• undertaking regular inspections of a building’s fire equipment or lifts

• servicing or repair of an air-conditioning system

• replacing or repairing solar panels

• replacing or repairing a damaged door

• repainting a wall in an existing home

• replacing or repairing carpet in a house not under construction

• replacing or repairing individual roof tiles.

Testing, maintenance or repair work is considered of a minor nature if it requires little or no pre-start preparation of the work area. It is small scale and involves minimal control measures. Minimal preparation of the work area includes:

• small scale work not impacting on the existing design or stability of the building or structure

• work completed using hand tools

• work with minimal effect on the public—that is, roads and footpaths are unaffected.

152. I am not satisfied that the work being conducted was repair work of a minor nature for the reasons that follow. First, it can be accepted that the job of applying the membrane sheets to the balcony floor was a small job within the scope of Danrae’s business, but it posed a significant risk of death or serious injury to the workers. Danrae recognised that the risk of a fire or explosion when using hazardous chemicals in waterproofing tasks created the highest risk of serious consequences that could only be reduced to moderate through the implementation of appropriate control measures. While the control measures were relatively simple and straight forward they were essential to avoiding potentially catastrophic consequences. Second, because the control measures involved workers understanding the risks of a hazardous chemical and complying with directions for its safe use, a SWMS was a more effective way of ensuring that the workers understood the risks and implemented the necessary control measures. Third, I do not think that it is appropriate to consider Danrae’s part of the remedial work in isolation. The remedial work required the removal of the tiles, the cladding and the balustrade from the balcony. The erection of scaffolding was required to provide safe access to the balcony and edge protection for the workers. Once the waterproofing had been completed, the remedial work involved replacing the tiles, cladding and balustrade on the balcony and removing the scaffolding. When considered as a whole I am not satisfied that the remedial work was repair work of a minor nature.

153. For these reasons, I am satisfied that the work was high risk construction work and that Danrae was required to have a SWMS in force for the work that complied with cl 299(2) of the Regulations. Such a SWMS could have been a generic for the kind of waterproofing work being undertaken that required the use of the adhesive.

154. If I am wrong in my conclusion that the work was high risk construction work and therefore Danrae was not required to have a SWMS for the work, I am satisfied that a written SWP for the use of the adhesive was required to ensure that the workers understood the risks posed by using the adhesive and the necessary control measures to be implemented for the reasons that follow.

155. First, notwithstanding that Mr Reid was an experienced waterproofer and considered himself to be an “Ardex expert” within Danrae, the evidence demonstrates that he did not understand some of the fundamental safety information provided for in the SDS and the Ardex training course. In his recorded interview Mr Reid stated that he did not think that the heat gun was an ignition source because it was “miles away” on the scaffold. He told Inspector Scott that he knew he had to keep the heat gun as far away as possible, but the heat gun and the adhesive were always used at the same time. The only ignition source he referred to in the telephone interview was a “naked flame”. Mr Reid clearly did not understand:

1. the content of the SDS that the vapour could travel a considerable distance to a source of ignition, that the vapour needed to be kept away from “heat / sparks / open flames / hot surfaces” and that the adhesive posed a severe fire hazard when exposed to heat, flame or other oxidisers, and

2. the content of the Ardex training course that the heat gun was a potential ignition source.

156. Second, a SWP was required to specify the PPE that Danrae required the workers to wear while using the adhesive. Mr Reid’s evidence was that while he knew the PPE that was provided for in the SDS, he had not been directed by Danrae to wear it when using the SDS.

157. Third, by failing to provide a written SWP in the present case, Danrae failed to adequately train Mr Bunyan on the risks posed by the adhesive and the appropriate control measures. Mr Reid’s evidence was that he was not aware of what Mr Bunyan had done with the heat gun prior to the incident. Whilst I think that Mr Reid’s evidence on this point was questionable and it is more likely that Mr Reid knew that Mr Bunyan left the heat gun on and did not think it would be a problem, I am satisfied on the evidence that Mr Bunyan had not completed the Ardex training course and was not familiar with the content of the pre-incident SWMS. I am satisfied that Mr Bunyan did not know that the heat gun was a potential ignition source or that leaving it on in the work area was dangerous.

158. For the reasons given, the pre-incident SWMS did not:

1. consider the SDS for the adhesive;

2. state the risks posed by the hazardous properties of the adhesive;

3. identify the heat gun as a potential ignition source; and

4. set out the critical control measures namely a direction that the heat gun should not be activated in the work area and the specification of the required PPE to be worn when using the adhesive.

159. The pre-incident SWMS did provide for the consideration of ventilation while using the adhesive. Having regard to Mr Hunt’s evidence referred to at [173], it would not have been reasonably practicable to specify the use of mechanical ventilation. I am satisfied that this aspect of the pre-incident SWMS did not require amendment. However, for the reasons given, Mr Reid did not use the SWMS to identify the relevant risks on the day of the incident or to provide adequate training to Mr Bunyan.

160. On 3 December 2021 Danrae implemented a SWMS entitled “Using Ardex WA98 in the proximity of the Leister Welder” (the post-incident SWMS). The post-incident SWMS:

1. stated that poor ventilation could lead to a build-up of vapours;

2. listed the heat gun as a potential ignition source;

3. included a direction that the heat gun was to be turned off and removed from the area when not in use.

161. Danrae also introduced a Safe Operating Procedure entitled “Applying Ardex WA98” in November 2021 (the WA98 SOP). The WA98 SOP:

1. pictorially depicted the required PPE to be worn when applying the adhesive;

2. contained a requirement to conduct a risk assessment of the work area and to ensure adequate ventilation of the working area, including the use of mechanical ventilation if necessary;

3. contained a direction to follow the training provided by Ardex, the SDS and PPE requirements;

4. advised that the solvents in the adhesive evaporated over 15-60 minutes and advised that the introduction of ignition sources should be avoided for the first 15 minutes;

5. advised that the potential hazards and risks of the adhesive included, vapour build up, a heat source could lead to ignition causing a fire or explosion;

6. prohibited the use of a heat gun in the vicinity of the adhesive because the vapour is highly flammable.

162. I pause to note that Danrae introduced the post-incident SWMS and the WA98 SOP to operate in combination.

163. The introduction of the post-incident SWMS and the WA98 SOP were steps taken by Danrae to comply with its s 19(1) duty and can be regarded as some evidence that the introduction of those safe work procedures was reasonably practicable. I am satisfied that the introduction of these safe work procedures containing reference to the essential risks and control measures was a straight forward and simple step that should have and could have been undertaken by Danrae prior to the incident. I am satisfied that the cost of devising and implementing a SWMS or SWP in accordance with particulars (a) and (b) was not grossly disproportionate to the risk.

164. I am satisfied beyond reasonable doubt that Danrae breached its s 19(1) duty by failing to take the reasonably practicable steps pleaded in [10](a) and (b) of the Summons.

165. As a final matter, I turn to deal with Danrae’s contentions that:

1. a SWMS or SWP would not have added much to Mr Reid’s training because at the time of the incident he was aware of the risks and the steps he needed to take to control them, and

2. it was not reasonably foreseeable that Mr Reid, an experienced and appropriately trained worker, would depart from a known safe procedure, and thereby it was not reasonably practical to guard against that possibility.

166. I reject these arguments for the reasons that follow.

167. First, for the reasons given, the evidence establishes that Mr Reid was not adequately trained because Danrae had failed to identify the risks posed by the adhesive, to properly instruct him and Mr Bunyan on those risks and the necessary control measures. Mr Reid and Mr Bunyan failed to understand that the vapour could travel long distances to an ignition source, that the heat gun was a potential ignition source and that it was dangerous to have the heat gun switched on in the area where the adhesive was being used. They each lacked that understanding because Danrae had failed to take reasonably practical steps to ensure that their training was adequate.

168. Second, the incident did not involve the unforeseeable behaviour of a disobedient employee that led to an event that could not be reasonably foreseen and therefore was not reasonably practical to guard against: WorkCover Authority of New South Wales v Kirk Group Holdings Pty Ltd (2004) 135 IR 166 at [129]. In this case, Mr Reid and Mr Bunyan failed to control the risk because they were not trained to keep the heat gun away from the work area where the adhesive was being applied. Mr Reid and Mr Bunyan did not disobey any direction to keep the heat gun away from the work area where the vapour could be present. It was foreseeable and actually known by Danrae from the Ardex training course that the use of a heat gun in the work area was a potential ignition source for the vapour. Mr Reid did not wear the PPE advised by the SDS that he knew should be worn, but he did not disobey a direction by Danrae to wear specified PPE when using the adhesive.

Failing to provide adequate training through the implementation of an adequate SWMS or SWP [6]

6. [10](d) of the Summons.

169. The introduction of an adequate SWMS or SWP would be entirely ineffective unless the workers were trained on it. In the usual course, workers are required to sign on to a SWMS to acknowledge that they have been trained on it and understand its contents.

170. The training provided on the post-incident SWMS and WA98 SOP was provided within a short period after the incident. Training was delivered through the use of an electronic platform and orally by reference to the improved safety documents. Proof of the training of the workers was documented by asking them to sign the SWMS, the completion of an attendance sheet at training sessions and the creation of electronic records of training on the Go1 platform. A record was also compiled of the issue of PPE to each worker.

171. I am satisfied that the defendant was not significantly inconvenienced by providing this training on the post-incident SWMS and the WA98 SOP. I am satisfied that the cost of the necessary training was not grossly disproportionate to the risk.

172. I am satisfied beyond reasonable doubt that Danrae breached its s 19(1) duty by failing to take the reasonably practicable step pleaded in [10](d) of the Summons.

Failing to provide mechanical ventilation as required when working with hazardous chemicals [7]

7. [10](e) of the Summons.

173. Mr Hunt gave evidence that the provision of mechanical ventilation on the balcony was not reasonably practicable because an electric fan would have been a potential ignition source for the adhesive. The only means of safely connecting a fan to a power source would have been expensive and potentially ineffective.

174. I am not satisfied beyond reasonable doubt that the provision of mechanical ventilation was a reasonably practicable step to take and the prosecutor has not made out this particular of breach.

Conclusion on Issue 1

175. I am satisfied beyond reasonable doubt that the prosecutor has established that Danrae breached its s 19(1) duty by failing to take the reasonably practicable steps pleaded in [10](a)-(d) and (f) of the Summons.

Issue 2   Did the defendant’s breach of duty expose the workers to a risk of death or serious injury?

176. The relevant principles are set out at [104]-[107] and I will not repeat them.

177. The relevant question to be determined in this issue is whether or not Danrae’s breaches of duty exposed the workers to a risk of death or serious injury irrespective of whether the vapour was ignited by the heat gun and thereby caused Mr Reid’s injuries. In other words, the offence does not require an incident or an injury to be sustained, but merely the creation of a risk to safety of an individual.

178. Danrae’s submissions on causation were difficult to follow. They seemed to be based on the premise that the fire was, or could have been caused by static electricity, or at least that it could not be ruled out as a potential cause of the fire. They did not really engage with the prosecution case that the workers were exposed to the risk of death or serious injury where the heat gun, a known source of ignition, was introduced to an area with a hazardous atmosphere.

179. Taking into account all of the evidence, I am satisfied that:

1. the use of the adhesive created a hazardous atmosphere in the work area where the concentration of the highly flammable vapour reached the flammable range; and

2. the decanting of the adhesive into the bucket and the use of the roller to spread out the adhesive on the sheets and the floor caused the dispersal of the vapour; and

3. the vapour being heavier than air dispersed across the balcony floor, where it was contained on three sides by the balcony door and the walls, causing the vapour to move towards the scaffold; and

4. the heat gun was switched on and situated on the scaffold; and

5. there was a significant and substantial risk of a fire or explosion if the vapour came into contact with the hot air being expelled from the heat gun or the heat source inside it.

180. I am satisfied beyond reasonable doubt that a significant and substantial cause of the risk was Danrae’s failure to identify the risks posed by the use of the adhesive by reference to the SDS and the Ardex training course, to adequately inform the workers of those risks, to implement the necessary control measure of directing that the heat gun was not to be used in the work area where the adhesive was being used and to adequately train the workers about the risks and the necessary control measures.

Conclusion on Issue 2

181. I am satisfied beyond reasonable doubt that the defendant’s failure to take the reasonably practical steps in [10](a)-(d) and (f) of the Summons exposed the workers to a risk of death or serious injury.

Issue 3   Was the heat gun the source of ignition for the fire?

Mr Hunt’s opinion

182. Mr Hunt opined that the heat gun was the ignition source based on the following reasoning that was additional to the matters I have set out at [57]-[69] above.

183. Mr Hunt opined that the fire was ignited behind Mr Reid because the heat gun was located behind where Mr Reid was standing because:

1. Mr Reid stated in his recorded interview that the bucket was in front of him at the time of ignition and that the fire started behind him; and

2. Mr Hunt accepted Ms Jones’ opinion that the burn pattern on Mr Reid’s legs indicated that the fire travelled from behind him, with the flames making first contact with his heels and back of his ankles and wrapping around to cause the more significant burns to the front of his shins. This opinion was not contradicted and I am satisfied that I should accept it.

184. Mr Hunt assumed from his reading of Mr Reid’s recorded interview and by looking at the post-incident photographs that the heat gun was located on the balcony at the time of ignition “on the scaffold side” of Mr Reid. Contrary to Mr Hunt’s assumption, I am satisfied that the heat gun was on the scaffold, however that does not undermine Mr Hunt’s analysis because the heat gun was still behind Mr Reid and in an area where the vapour was likely to flow to. I am satisfied that Mr Hunt’s assumption that Mr Reid was facing the balcony door was correct because it was consistent with Mr Reid undertaking the task of applying the adhesive and supported by Mr Reid’s statement that the bucket was in front of him when the ignition occurred. I do not accept Mr Reid’s evidence that the bucket was behind or beside him at the time of ignition because I am satisfied that the statements he made in his recorded interview were more reliable because they were made closer in time to the event and were less likely to be influenced by his loyalty to Danrae. I accept that Mr Reid’s statements that the fire started behind him may have reconstructed to some extent and on their own may not have been reliable, but by reference to the other available evidence I am satisfied that they were correct.

184. Mr Hunt described the likelihood of the vapour being ignited by the heat gun as “extremely probable”. Mr Hunt accepted that there was a possibility that static electricity ignited the fire but stated that it was not a “reasonable hypothesis” within the meaning of the NFPA 921 Guide for Fire and Explosion Investigations (the NFPA 921) for the following reasons:

1. the relative humidity at the time of the ignition was high and this significantly reduced the chance of the generation of a static electricity charge;

2. there was no evidence that a static charge was generated at the time when the roller was put into the bucket;

3. there was no suggested method of creating a static charge that was capable of being a source of ignition; and

4. the ignition of the fire behind Mr Reid was inconsistent with the suggested methods of ignition by static electricity.

186. I will deal with each of these in turn, except (d) which I have dealt with above.

187. Mr Hunt opined that the relative humidity at the time of ignition was high because it was raining. It was not possible to calculate the precise level of humidity because there was no wet bulb temperature available for the date of the incident. Mr Hunt suggested a relative humidity of around 70% at the time of the incident based on the information that he obtained from the Bureau of Meteorology (BOM) to the effect that based on 30 years of data between 1978 and 2008 that the average humidity at 9.00am for the month of November in Sydney would be about 60% but closer to 70%. Mr Hunt relied on published studies to demonstrate that high relative humidity in excess of 65% significantly reduces the accumulation of static electricity [8] to the extent of a 96% reduction in the energy of a static charge at a relative humidity of between 65% and 95%. [9]

     8. Gibson and Lloyd 1965

     9. NFPA 921 table 9.14.2.8

188. Mr Hunt noted that there was no evidence of the removal of clothing by Mr Reid or Mr Bunyan or any other activity that was likely to create static electricity, and accordingly it was unlikely that the workers’ clothing was a potential source of static electricity. In addition there was no suggested method by which the static electricity was discharged in a location close to the floor where the vapour had settled.

189. Mr Hunt stated that the use of the roller to apply the adhesive was unlikely to be the source of static electricity because if it was, it would have started the fire in front of Mr Reid.

190. Mr Hunt accepted that static electricity could be generated within the adhesive if it was pumped through a pipe but did not accept that a significant amount of static electricity would be generated by decanting of the adhesive into the bucket in this case.

191. Danrae relied heavily on Mr Reid’s evidence that the adhesive ignited when he placed the roller back into the bucket to suggest that the fire was ignited in the bucket. In response to this hypothesis, Mr Hunt opined that assuming the roller was statically charged it could not have ignited the adhesive because the concentration of the vapour immediately above the adhesive would have been in excess of the UEL and too rich to ignite, and it was impossible for the static electricity to discharge on the surface of the adhesive. In order to discharge any static electricity in the roller it would have had to come close to a grounded metallic object that it could arc to. Mr Hunt accepted that it was possible that the static electricity could have arced to a metal handle on the bucket and ignited vapour above and around the bucket but opined that this was highly unlikely because the fire started behind Mr Reid when the bucket was in front of him and the high relative humidity made the generation of a static charge unlikely. I would add to Mr Hunt’s reasons that the application of the adhesive with a roller was a method recommended in the Ardex training course and there was no warning given that by doing so there was a risk of ignition from static electricity.

Ms Jones’ opinion

192. Ms Jones stated in both of her reports that she based her opinions on the application of the systematic approach set out in NFPA 921. Ms Jones opined that it was possible that the vapour could have been ignited by static electricity and that it could not be ruled out entirely.

193. Ms Jones accepted that at a relative humidity of between 60% and 70% that the likelihood of a static discharge is reduced because there is a microscopic layer of moisture accumulated on the surface area of items which is more conductive than the substrate and allows for the leakage/breakdown of a static charge.

194. Ms Jones opined that it was possible that a person using a synthetic roller, who was insulated by wearing footwear, could create a positive charge that may be released from the roller on the surface of the adhesive and thereby ignite the vapour. I do not accept Ms Jones’ opinion that this was possible because I prefer the evidence of Mr Hunt that at the surface of the adhesive in the bucket the concentration of the vapour was above the UEL and too high to ignite and there was no means by which the static electricity could be discharged through a grounded metallic object.

195. Ms Jones opined that if Mr Reid’s clothing was partially synthetic then the capacity to generate static electricity would be higher than normal. Ms Jones noted that she did not have any information about what Mr Bunyan was wearing.

196. Ms Jones opined that the ignition of the fire originated from behind Mr Reid because he told the Inspectors that the fire originated from behind him when he was facing away from the scaffold, that he did not identify flames or a fireball originating in or around the bucket in front of him and that the burns to his legs suggested the fire came from behind him. I pause to note that this is consistent with Mr Hunt’s opinion.

197. Ms Jones stated that to consider that the fire was ignited from static electricity from Mr Bunyan’s clothing it was important to know where he was standing and what he was doing at the time of ignition, in particular if he was touching a metal object such as the scaffold or the heat gun, noting that if Mr Bunyan was touching the scaffold at a height above floor level that a static charge was unlikely to ignite the vapours at floor level. I pause to note that this statement of possibility by Ms Jones was not based on any evidence given to her of what Mr Bunyan was doing or what he was wearing at the time of ignition and it involved a high degree of speculation.

198. In cross-examination Ms Jones agreed that the concentration of the vapour was more likely to reach the flammable range the further it travelled away from the bucket and that would have made the heat gun which was on the scaffold, a competent ignition source.

199. Ms Jones agreed that the NFPA 921 stated that static electricity was less likely to be generated where the relative humidity was 50% or higher.

200. Ms Jones agreed that the NFPA 921 stated that in the investigation of ignition by static electricity it was necessary to examine circumstantial evidence and to eliminate other ignition sources, because ignition by static electricity does not leave physical traces of arcing. Ms Jones agreed that the heat gun could not be excluded as an ignition source and that it was in fact the most probable ignition source.

201. Ms Jones agreed that the relevant factors to be established for static discharge to be a source of ignition are: [10]

     10. NFPA 921 at 9.14.6

1. There must be an effective means of static charge generation.

2. There must be a means of accumulating and maintaining a charge of sufficient potential.

3. There must be a static electricity discharge of sufficient energy.

4. There must be a fuel source in the appropriate mixture with a minimum ignition energy less that the energy of the static electric arc.

5. The static arc and fuel source must occur together in the same place at the same time.

202. I will deal with each of factors (1)-(3) and (5) because (4) can be accepted as existing for ignition to occur in this case.

203. As to factor (1), Ms Jones’ enquiry was based on Mr Bunyan’s clothing and activities because the fire was ignited behind Mr Reid. In her first report, Ms Jones’ comments were that she needed more information to determine where Mr Bunyan was at the time of the ignition, if the static charge could have been generated by Mr Bunyan’s clothing and if it was discharged by him. In her second report, Ms Jones did not take the issue further. There was no evidence that Mr Bunyan was wearing clothing or undertaking an activity that was likely to generate a static charge or even that he was standing behind Mr Reid. Her comments that Mr Bunyan may have been the source of the static charge did not rise above speculation.

204. As to factor (2), Ms Jones accepted that the high relative humidity would have made the accumulation and maintenance of a static charge of sufficient potential less likely. I accept the evidence of Mr Hunt that the weather conditions made the accumulation and maintenance of a charge of sufficient potential highly unlikely.

205. As to factor (3), the NFPA 921 estimated that the potency of a static charge could have been reduced by up to 96% once the relative humidity was in excess of 65%. I am satisfied that the discharge of static electricity of sufficient energy was very unlikely.

206. As to factor (5), Ms Jones accepted that there was no evidence of the discharge of static electricity from either of the workers. Ms Jones also accepted that the static charge would have to have been discharged fairly close to the floor. There was no evidence that Mr Bunyan was performing an activity close to the floor that could have discharged a static charge and that was very unlikely because if he was performing such an activity, I would have expected him to have been so close to the ignition source that he would have suffered burns.

Other matters

207. The evidence of Inspector Grillo was that static electricity was a potential source of ignition, but that he had not tried to assess whether or not this was a reasonable hypothesis. Nothing in his evidence was significant to the resolution of Issue 3 and I am satisfied that his evidence does not cause me any reasonable doubt.

208. There was no direct evidence of the setting that the heat gun was on at the time of the incident. Mr Reid gave evidence that he used the heat gun at between settings 6 and 7 for heat welding the sheets together, but he had not undertaken that task before the fire occurred. Mr Bunyan could not recall at what setting the heat gun was used. Any setting above 2-3 out of 10 would have been sufficient to auto ignite the hexanes solvent in the vapour

209. From Mr Reid’s evidence, I infer that a setting above 6.5 out of 10 was too hot for the task of welding the membrane sheets.

210. I am satisfied that the heat gun was on a setting greater than 3 out of 10 because it was more likely that the heat gun was on a setting of 3-10 out of 10 as opposed to a setting of 1-3 out of 10 and the task of drying the balcony with the heat gun would have been achieved quicker if the heat gun was on a higher setting.

211. I am satisfied that the heat gun was on a setting that caused the ignition of one of the solvents in the vapour.

Conclusion on Issue 3

212. I am satisfied that the vapour from the adhesive spread across the floor of the balcony, where it was confined on three sides. This caused the vapour to spread towards the scaffold where it was ignited by the heat gun, which was located behind Mr Reid.

213. I am satisfied that there was no evidence to demonstrate a number of the crucial factors required to conclude that static electricity was a potential ignition source and that the suggestion that this was a reasonable possibility did not rise above speculation.

214. I am satisfied beyond reasonable doubt that the vapour of the adhesive was ignited by the hot air being expelled by the heat gun or the heat source inside it.

Verdict

215. I am satisfied beyond reasonable doubt that the prosecutor has proved the elements of the offence.

216. I find the defendant guilty of the s 32 offence.

**********

Endnotes

Amendments

21 May 2025 - Date in [2] changed from 12 November 2011 to 12 November 2021.

Decision last updated: 21 May 2025