[4] At the junction of the pipe work, a ball valve rated at 300 p.s.i. was in the closed position isolating the hydrogen, and alongside this, between the valve flange and the nitrogen filled pipe flange was a spade. A spade, or spectacle blind, is a dual ended steel plate which has a large diameter opening at one end surrounded by a perimeter of steel plate to fit between bolt-on flanges. The open end allows a flow of gas or fluid, and the other end has complete steel plate which denies any flow and forms a positive isolation of gas or fluid.
[5] A pipe flange is a steel ring welded to the end of a pipe through which bolts can be fitted for a leak proof seal. The valve used also had a flange face for bolting to the pipe flange. A gasket was also fitted between flanges to enhance the seal properties.
[6] On 29 November 2002 at approximately 2.30pm, Victor Plescan and Tihomir Boka were standing on the scaffold and had spanners on the flange bolts for the purpose of turning the spade plate from the closed position to the open flow through position.
[7] Shell senior operator Mario Cabello was overseeing the procedure and was standing behind the scaffold, approximately 1.5 metres away. Another Shell operator, Chun Guo was standing beside Mario Cabello, also watching the procedure.
[8] During the procedure, the fitters were loosening the bolts and low-pressure gas was released. This was nitrogen gas used to purge the pipeline and to prevent air from entering the pipe. The fitters, as a precaution, were keeping their hands on the spanners in case of an abnormal release of gas in order that they could re-tighten the bolts, as directed by Shell senior operator Mario Cabello.
[9] As the low pressure gas reduced in volume there was a sudden gush of another substance. The substance of escaping hydrogen or hydrocarbon gas ignited while the fitters had spanners on flange bolts. The origin of the escaping gas preceding the fire has not been determined.
[10] The fire started almost instantly, with a ring of flame several metres in diameter that receded to approximately one metre in diameter. Tihomir Boka was able to escape from the scaffold. Victor Plescan was on the other side of the fire with no escape route from the scaffold. He had to exit through the flames. It is believed that his exit was impeded by an emergency breathing bottle strapped to his leg becoming caught on scaffolding or pipe fittings. Tihomir Boka returned to the scaffold seconds later. He pulled Victor Plescan from the flames. At the time they were both wearing air supplied masks. The fire continued for several minutes while Shell employees attempted to isolate the hydrogen gas and assess other possible sources of fuel. Persons at the scene directed Victor Plescan to a shower in the central control room.
[11] There was no specific documented procedure for the task of turning a spade on a potentially live pressure line. There was a job safety analysis undertaken by the defendant in relation to the work being carried out and there was a talk about how the job was to be done including a whiteboard sketch. The Job Safety Analysis did not take account of the presence of hydrogen and there was an inadequate risk assessment in respect of the work being undertaken.
[12] The defendant's fitters undertook the procedure of loosening the flange bolts in consultation with Dennis McCone, the Shell Process West plant controller, and Shell operations employees. The fitters were undertaking the work as a part of the recommissioning of a unit that was not modified to treat hydrogen-rich platformer gas (approximately 85% hydrogen and 15% LPG).
[13] The Job Safety Analysis Risk assessment conducted prior to the commencement of work failed to identify or analyse the possibility of hydrogen being present in the line. The Analysis and talk which took place dealt with the risk of nitrogen gas escape. The Shell operator provided the Defendant's employees with a permit to work and confirmed that the work could be carried out. The risk assessment failed to require the defendant's employees to check that the permit issued was appropriate for the work. Previous job safety analysis worksheets supplied by the defendant indicated the potential hazard of a release of product under pressure was to be addressed by depressurising lines, and also listed retightening bolts if pressure was detected.
[14] There was no appropriate procedure used by either Shell or the defendant that addressed the hazard of hydrogen gas being present prior to the fitters removing bolts from the flange. Shell used an increased hazard permit for air breathing equipment to address the nitrogen gas hazard but neither the defendant nor Shell assessed the risk of a hydrogen leak.
[15] The fitters should have been able to stop the job when an adequate risk assessment or job safety analysis was not done.
[16] The defendant's employees did not know what pressure was contained in the pipe with the nitrogen, or the rate of reduction of pressure during the release of gas from the flange area over time.
[17] There was limited knowledge of the risk of static explosion or fire amongst the defendant's fitters.
[18] There was electrical equipment approximately 800mm from the source of the gas leak that should have been assessed as a possible source of ignition. The area was classified as zone 1 due to the risk of hydrocarbons being present at any time.
[19] Any gas passing the ball valve should have been contained by the positive isolation of the spade, until the bolts were loosened.
[20] The hydrogen rich gas in the pipe should have been purged free of flammable gas before the procedure. The procedure of turning the spade was seen as a minor job.
[21] Neither the defendant nor Shell assessed the scaffold for appropriate emergency exits. The use of emergency air bottles dictated the provision of a second escape route according to Australian Standards. One escape route on either side of the valve, and possibly a larger platform, would have assisted Victor Plescan's escape from the fire.
[22] There existed a potential for an escalation of the fire in a refinery classed as a major hazard facility.
[23] The isolation of the hydrogen after the fire was delayed due to a shut off valve nearby still passing gas although being shut off manually.
[24] The defendant's fitters should have been wearing flame resistant clothing.
[25] An adequate risk assessment would have demonstrated that the procedure should have been halted temporarily while the Shell operator, Chun Guo, went to get gas detecting equipment after realising that the gas released from the flanges was unidentified.
[26] As a result of the incident, Victor Plescan suffered 35% burns on his right arm, hand, the back of his scalp, both ears, back, left hand, the entire left thigh and knee, right calf and left thigh. He has had to have skin grafts on most of the right arm, right calf and left thigh. He also tore the ligaments of his right shoulder. As at 16 January 2003 Mr Plescan had not yet returned to work. Tihomir Boka was placed at risk of injury and received trauma treatment on the day of the incident but otherwise did not suffer injury.
[27] Subsequent to the accident, the following measures were implemented:
(a) Shell and Transfield participated in a TRIPOD incident investigation. Shell also sought technical assistance from Shell Global Solutions Singapore.
(b) A documented job safety analysis was conducted on 30 November 2002 for the renewal of the suspected passing valve. Danger tags, depressurisation, nitrogen gas purging, barriers and safety monitors were in place for the procedure.
(c) In January 2003 The defendant submitted a documented procedure to Shell entitled "Breaking flanges, couplings, joints on process lines" indicating that a material safety data sheet be obtained and a thorough risk assessment or job analysis be developed and discussed amongst all personnel undertaking the work. The document also addresses isolation, danger tags, depressurisation, purging of line contents and work permits. The procedure includes a checklist for operators.