1998 жылғы Аустралиядағы газ зауытының апатты жағдайы

1998 industrial disaster in Victoria, Australia

On 25 September 1998 a catastrophic accident occurred at the Esso natural gas plant in Longford, Victoria, Australia. A pressure vessel ruptured resulting in a serious jet fire, which escalated to a conflagration extending to a large part of the plant. Fires lasted two days before they were finally extinguished. Two workers were killed and eight others injured. while financial losses to the companies affected by the gas shortage were estimated at around A$1.3 billion. Gas Plant 1 was a lean oil absorption plant separating methane from liquefied petroleum gas (LPG) by stripping the gas using a liquid hydrocarbon stream called "lean oil" (a light oil similar to aviation kerosene).

There were several precursors to the breach of containment that escalated to the fire. Post event analysis was difficult due to the complex interconnections and interactions between different plant streams. This complexity was probably also a factor that made the diagnosis of the plant upset very challenging for the operators and may have contributed to causing the accident. During the morning of Friday 25 September 1998, a pump supplying heated lean oil to shell and tube heat exchanger GP905 in Gas Plant 1 tripped. This was likely due to high level of liquid in one of the process drums, which in turn was caused by excess liquid overflowing from the demethaniser column. This chain of events was probably initiated by an increase in flow from the Marlin gas field. A heat exchanger is a vessel that allows the transfer of heat from a hot stream to a cold one. It does not operate at a single temperature, but experiences a range of temperatures throughout the vessel. Temperatures through GP905 normally ranged from Due to the stoppage in the flow of the heating medium and the continued inflow of cold process fluid on the shell side of the exchanger, parts of GP905 experienced temperatures as low as Ice from condensed atmospheric humidity formed on the unit shell. The same occurred elsewhere in the plant (for example on heat exchanger GP922), where cryogenic fluid was present which, under normal circumstances, would have been hot. A decision was taken to shut down the entire Gas Plant 1. Once the faulty pump was restarted, hot lean oil was pumped into the heat exchanger at At 12:26 pm the steel of the exchanger outer shell, embrittled due to exposure to temperatures far below its safe design envelope, gave way due to thermal stress. About 10 tonnes of hydrocarbon were immediately vented from the rupture and flashed. A vapour cloud formed and drifted downwind. It ignited 60–90 seconds later, when it reached a set of fired heaters away. This caused a deflagration which quickly burnt its way back to the leak source. When the flame front reached the rupture in the heat exchanger, a fierce jet fire developed. There was however no blast wave and the nearby control room was undamaged. The plant supervisor and a maintenance supervisor were killed in the initial fire. The jet fire burnt beneath a critical pipe rack section colloquially known to the operators as "King's Cross". In a case of domino effect accident, over a 30 minute period from 13:00 to 13:32, impinging flames led to three other releases of large flammable inventories. A full blown plant conflagration ensued.

Complete isolation of the pipes feeding the fire required nearly two and a half days, as a result of the interconnections between the three gas plants. Consequently, it was not possible to extinguish the fire until 17:30 on 27 September. Gas production, however, had been shut down immediately, and the state of Victoria was left without its primary gas supplier. Within days, VENCorp shut down the state's entire gas supply. The resulting gas supply shortage was devastating to Victoria's economy, crippling industry and the commercial sector. 1.4 million households and 89,000 businesses were affected. As natural gas was also widely used in houses in Victoria for cooking, water heating and home heating, many Victorians endured 20 days without these facilities. Gas supplies to Victoria resumed on 14 October. Many Victorians were outraged and upset to discover only minor compensation on their next gas bill, with the average compensation figure being only around $10.

A royal commission was called on 12 October 1998, The Longford Royal Commission sat for 53 days, commencing with a preliminary hearing on 12 November 1998 and concluding with a closing address by Counsel Assisting the Royal Commission on 15 April 1999. Esso blamed the accident on plant operators negligence, even producing the training records of one particular operator in an attempt to show he should have known how to manage the plant upset. The findings of the Longford Royal Commission, however, focused on Esso's safety practices rather than on actions by individual operators:

Esso was taken to the Supreme Court of Victoria by the Victorian WorkCover Authority. The jury found the company guilty of eleven breaches of the Occupational Health and Safety Act 1985, and Justice Philip Cummins imposed a record fine of A$2 million in July 2001. In addition, a class action was taken on behalf of businesses, industries and domestic users who were financially affected by the gas crisis. The class action went to trial in the Supreme Court on 4 September 2002, and was eventually settled in December 2004 when Esso was ordered to pay A$32 million to businesses which suffered property damage as a result of the incident. Following the Longford accident, Victoria introduced the Major Hazard Facilities Regulations to regulate safety at plants that present major process hazards. The regulations impose a non prescriptive regime on facility operators, requiring them to demonstrate control of major hazards via the use of a safety management system and a safety case. As a result, about fifty major hazard facilities had to develop and submit a safety case by 30 June 2002 to the regulator WorkSafe, a division of the Victorian Workcover Authority. Other Australian states have also implemented similar regulatory regimes.