The accident Extract from Longford Royal Commission report: 1.1 At Longford in south-eastern Victoria, Esso Australia Resources Ltd (Esso) operates three gas plants to process gas flowing from wells in Bass Strait. It also operates a Crude Oil Stabilisation Plant (CSP) at Longford to process oil flowing from other wells in Bass Strait. The gas plants are known as Gas Plant 1 (GP1), Gas Plant 2 (GP2) and Gas Plant 3 (GP3). 1.3 On Friday 25/9/98, at about 12.26 in the afternoon, a vessel in GP1 fractured, releasing hydrocarbon vapours and liquid. Explosions and a fire followed. Two Esso employees were killed. Eight others were injured. Supplies of natural gas to domestic and industrial users were halted. 1.4 The vessel which failed was a heat exchanger, GP905. It was also known as a demethaniser reboiler because it operated to heat rich oil at the bottom of a piece of equipment known as a Rich Oil Demethaniser (ROD). Near GP905 was another heat exchanger, GP922, which preheated rich oil flowing from the ROD on its way to the Rich Oil Fractionator (ROF). GP922 had developed leaks at its flanges some time before the accident and attempts were being made to repair them at the time GP905 failed. 1.5 Immediately before its failure, the temperature of GP905 was well below its normal operating temperature and may have been as low as -48 degrees Celsius. The normal operating temperature was in the vicinity of 100 degrees Celsius. The low temperature of GP905 was due to the loss of lean oil flow in GP1. Hot lean oil flowing through GP905 was the means by which it was heated to its normal operating temperature. 1.6 The lean oil flow in GP1 stopped when the pumps known as the GP1201 pumps tripped and were not restarted. Notwithstanding the loss of lean oil flow, cold rich oil and, subsequently, cold condensate continued to flow through GP905 causing its temperature to drop. 1.7 The GP1201 pumps were out of operation for some hours. When they were eventually restarted there was a flow of warm lean oil into GP905 for a short time. The higher temperature of the lean oil flowing into the cold reboiler caused stress in the vessel. This resulted in its brittle fracture at one end. 1.8 The rupture of GP905 released a large volume of hydrocarbons in the form of vapour. The vapour subsequently ignited giving rise to a series of explosions and fire. The fire was not fully extinguished until 27 September 1998. 1.9 Because of the explosions and fire, all three gas plants at Longford were shut in and supplies of gas ceased. The final restoration of gas supply to all consumers took place by 14 October 1998. (Further technical explanation of the event can be found in the Royal Commission report ‘The Esso Longford Gas Plant Accident: Report of the Longford Royal Commission’.) A large contingent of emergency services responded to the fire, including fire fighters, ambulance officers, police officers, Red Cross personnel and Workcover inspectors. Residents living within five kilometres of the plant were evacuated and roads closed. Impact on Victorian gas supply The disaster immediately severely affected Victoria’s domestic, commercial and industrial use of gas for a fortnight. This was the second time Victorians had been impacted by gas shortages. Gas supplies had been disrupted in June of the same year when an ice plug disrupted normal services at the Longford plant. The Longford plant was the primary source of Victoria’s gas. Only very small amounts of gas were available to Victorians during the gas crisis. This supply came from the pipeline link from Wagga Wagga to Wodonga (bringing gas from the Cooper/Eromanga Basin via New South Wales), and the gas supplied to the Warrnambool Portland region from the small gas fields in the Otway Basin. These sources of gas supplied only minimal amounts of gas compared to Victoria's total requirements (Parliament of Australia, Parliamentary Library Research Paper 5 1998-99: Natural Gas: Energy for the New Millennium). To prevent a complete run-down of reserves, dwindling supplies of gas were prioritised to essential services only, such as hospitals. About 1.3 million households and 89,000 businesses were affected by the disaster and export earnings alone were cut by over $200 million. Stand-downs and production losses for affected Victorian and interstate businesses and factories were initially estimated by the Victorian Employer’s Chamber of Commerce and Industry to cost up to a billion dollars (ABC Online 5/8/1998). This figure was later revised to $1.3 billion as reported by the Financial Review, 27/4/99 (and other sources). On 2 October 1998, a $100 million Federal Government assistance package was announced for Victorians affected by gas shortages. On 12 October 1998, the Victorian Government announced a Royal Commission into the two gas stoppage incidents in order to determine the cause of the 25 September explosion and the subsequent loss of supply (Parliamentary Research Paper). Refer to related documents below for the Royal Commission’s Terms of Reference. The Director of Public Prosecutions took Esso to court in relation to breaches of the Occupational Health and Safety Act 1985. The Supreme Court of Victoria convicted Esso of 11 counts of breaching ss 21 and 22 of the Act (refer to related website below for the Judge's sentencing statement). The Premier of Victoria recommissioned the Longford Gas Plant on 13 March 2002. The plant was rebuilt at a cost of $500 million and incorporated new safety measures and staffing increases. Esso also announced that it would invest a further $100 million in the development and expansion of the Longford plant over the next two years (The Premier of Victoria Australia News Archive 13/3/2002). The Victorian Government has established gas supply redundancies and has acted on the recommendations of the Longford Royal Commission, including the implementation of a rigorous safety regime for hazardous sites. Related documents: |