Systems in place prior to incident
34. For a period of approximately two years prior to the subject incident, Wingruby retained the services of Eric Young Consulting Pty Ltd, an OH&S consultancy.
35. The consultancy provided Greg Nelson with advice and documentation used in the development of Wingruby's formal OH&S management systems, including an OH&S & Injury Management System manual, written safe work method statements [which are described as a "Risk Assessment/Work Instruction"] and other documentation such as site and tool inspection documentation OH&S meeting records, and training attendance records. The consultancy also provided some training including formal induction training, manual handling training and training with respect to written safe work procedures.
36. However Eric Young, the principal of Eric Young Consulting Pty Ltd, stated that he had only done general risks assessments for changing tyres for Wingruby. He stated that there were two such risk assessments: the first for smaller tyres; and the second for larger tyres, including split rims with locking rings. Eric Young further stated that his consultancy had not been retained by Wingruby to undertake or develop a risk assessment with respect to two-piece divided rims for forklifts. Yet, Eric Young also stated that the Lithgow Tyre Service safe work method statement dated 5 May 2004 and bearing document number LTS SWP 002, of which he was the author, would have applied to the subject wheel and tyre assembly.
37. When spoken to after the event Greg Nelson, Ben Futcher, Mark Langbein and Tim Bennett all stated that Wingruby had in place a safe work method with respect to fitting a new tyre to a divided two-piece rim, including a divided two-piece forklift rim of the type involved in the subject incident.
38. Further, Wingruby produced a written safe work method statement, dated 5 May 2004, titled " Lithgow Tyre Service - Risk Assessment/Work Instruction" document number LTS SWP 002, for a task described as "Tyre Replacement."
39. When interviewed after the event, Ben Futcher stated that Wingruby provided the written work procedure for changing industrial tyres in general, including two-piece divided forklift rims of the type involved in the incident.
40 However, when interviewed, Greg Nelson also stated that the written safe work method statement produced from Wingruby's records applied only to "split rim" assemblies and not to two piece divided rims of the kind involved in the subject incident.
41. Greg Nelson also stated that employees were trained to perform risk assessments with respect to each type of rim on which they worked, including two-piece divided rims of the type involved in the subject incident. These risk assessments were to be unwritten risk assessments performed informally on the job.
42. Further, Greg Nelson, Ben Futcher, Mark Langbein and Tim Bennett each stated that training with respect to the safe working procedures and the risk assessment procedures to be followed when fitting tyres, including the fitting of tyres to two piece divided rims of the kind involved in the subject incident, was provided informally on the job. In particular, Greg Nelson also stated that on three or four occasions Scott Mason had changed tyres on two-piece divided rims whilst he was present.
43. Where a pneumatic tyre is repaired or replaced on a two piece divided rim, there is a risk of an explosive release of air upon inflation. Tyres of the subject kind operate between 80-100psi.The greater the pressure to which a tyre is inflated the greater the force to be released upon failure of the tyre and /or rim.
44. In the case of two-piece divided rims, the risk of an explosion is greater because the nuts and/or studs can give way as the pressure increases, allowing the two halves of the rim to separate. Where the nuts and/or studs fail, the separation of the two halves can occur with explosive force.
45. As damage to the threads on the nuts and studs increases the risk of failure, the following are factors that have been identified as increasing the risk of two piece divided rims of the type involved in the subject incident failing:
· cross threading
· stripping of threads
· corrosion of threads
· contamination of the threads
· other damage.
46. When spoken to after the event, Greg Nelson stated that, when working with Scott Mason on a two piece divided forklift rim, he had shown Scott Mason how to identify worn studs and nuts. Greg Nelson also stated that Scott Mason had been trained not to fit tyres where worn nuts and studs had been identified and to report the damage.
47. Further, the threads on the nuts may be damaged by applying too much torque when tightening the nuts.
48. The nuts on the subject rim were examined after the event and appeared to be consistent with 7/16" Grade 5 UNF nuts. Upon examination, a total of eight nuts were located with the majority of the internal threads either worn or stripped. Out of the eight nuts examined, only three of the nuts fitted the studs on the split adequately. The remaining five nuts were found to be loose with very little thread left to engage in the stud threads.
49. During the examination of the outer half rim, it was found that there were 11 studs fitted with one missing from the 12 in total. The stud hole of the missing stud was encrusted with scale and dirt indicating that a stud had not been fitted for a long period.
50. The studs were examined with parts of stripped threads located on three of the 11 studs. Further examination of the studs revealed that another three of the studs may not have had any nuts installed for some time due to the coating of dirt around the threads. There is no evidence that the stripping of the nuts was caused by Scott Mason.
51. Ajax Engineered Fasteners - a manufacturer of threaded fasteners for use in automotives and industry, including both bolts and nuts of the kind used to fasten together the two portions of two piece divided rims of the type used on forklifts, provide recommended torque settings for the level of torque to be applied when tightening threaded fasteners. These recommended levels of torque are intended to reduce the risk of the thread being stripped from the fasteners whilst they are being tightened. For example, Ajax Engineered Fasteners publishes the Ajax Threaded Fastener Handbook in which the recommended torque settings for their products may be found. According to the Ajax Fastener Handbook, the risk of damage to the thread is increased when anti-seize is used and the level of torque used when tightening threaded fasteners should be decreased when anti-seize is used. The Ajax Threaded Handbook also states that the appropriate level of torque to be applied to 7/16" Grade 5 UNF fastener manufactured by Ajax is 33.6lbft. "7/16"" refers to the size of the fastener; "Grade 5" refers to an international standard relating to the hardness of the steel used in the manufacture of the subject fastener; and "UNF" refers to the design of the thread. "Grade 5" nuts are made from hardened steel.
52. The defendant had available for its employees in the workshop a Njoy Universal Tyre Fitment Guide (Njoy Guide) for passenger, soft road, four wheel drive and light commercial vehicles. The Njoy Guide contains general reference material for tyre fitting including torque settings of nuts and stud bolts. However the defendant did not supply its employees with information concerning the need to have regard to the manufacturer's recommended torque settings and/or the hardness of the materials from which threaded fasteners are manufactured when identifying or determining the appropriate level of torque to be applied when tightening threaded fasteners, such as the bolts or studs and nuts used to fasten the two portions of the two piece divided rims of the type used on forklift trucks. Neither Mr Nelson nor any other employee of the defendant had expertise in metallurgy or any other field related to the hardness of materials.
53. A torque wrench and extension fitted with an 11/16" socket was located in the area in which the deceased was working on the rims and seized by the Police. When examined the torque wrench was found to be set at a torque of 88.5lbft.
54. Similarly, a 1/2inch drive air impact wrench, fitted with 7/16" socket, was also located in the area in which the deceased was working on the rims and seized by the Police. When located, the air impact wrench was not connected to an air hose but, an air hose was connected to an air outlet on the front wall between the first and second work bays.
55. When examined the air impact wrench was set on the highest of 4 torque settings.
56. When interviewed after the event Greg Nelson stated that Wingruby's practice was for the air impact wrench to be set on the lowest level.
57. Greg Nelson also stated Scott Mason had been instructed with respect to the tightening of the nuts that, when re-assembling a two piece divided rim of the type involved in the subject accident:
"Do the nuts up firm on a low setting with the impact wrench and check with the tension wrench or bar because when you do it up you are holding it and doing the nuts up firm."
58. In these regards, no training records were produced by Wingruby.
59. Prior to and at the time of the subject incident Wingruby provided a tyre cage in its workshop and required its employees to inflate larger tyres in that cage.
60. Wingruby did not require that any cage be used when inflating the tyres on such assemblies following the repair or replacement of tyres. Due to the size of the gaps in the cage provided by Wingruby for use by its employees when inflating tyres on other types of rims, the cage was not suitable for use with tyre and rim assemblies of the size involved in the subject incident.
61. Further, prior to and at the time of the subject incident, it was the practice, when inflating tyres on two piece divided rims of the type involved in the subject incident to inflate the tyres with the tyre and rim assembly resting on the top of a tyre fitting machine located in the workshop, known as a Beissbarth "MS 50 IT Tyre Changer". This was the machine on which Mark Langbein observed Scott Mason inflating the subject two piece divided rim and tyre assembly just prior to the subject incident and it was the machine Scott Mason was trained to use.
62. However, this machine was not designed to "hold" rim and tyre assemblies of the size and design involved in the subject incident and, although the machine was fitted with an inertia reel style tyre restraint, it could not be used to secure rim and tyre assemblies of the size and design involved in the subject accident whilst those tyres were being inflated. Greg Nelson stated after the incident that Scott Mason was trained to use the restraining device on the machine with split rim tyres and not two-piece divided rims of the type involved in the subject incident.
Investigation of the Incident
63. On 7 May 2007, Inspector Ken Evans attended the site and made observations contained in a Factual Inspection Report dated 10 May 2007 which is annexed and marked ' A '.
64. On 7 May 2007, whilst at the site Inspector Evans took a number of photographs which are annexed and marked ' B.
65. On 8 May 2007, Inspector Karen Simpson issued Wingruby an Improvement Notice (No 7-130370) with respect to employees being "exposed to risks to their health and safety when changing forklift tyres that have a two piece wheel assembly when the pieces separate under pressure when tube being inflated". Improvement Notice No 7-130370 is annexed and marked " C ".
Systems of work after the incident
66. After the incident Wingruby stopped performing repairs and tyre changes on tyre and rim assemblies of the type involved in the incident.
The Defendant's Criminal History
67. The defendant has no criminal history.