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Revision as of 21:30, 31 May 2006 by Carcharoth (talk | contribs) (add category)(diff) ← Previous revision | Latest revision (diff) | Newer revision → (diff)The 1998 Esso Longford gas explosion was a catastrophic industrial accident which occurred at the Esso natural gas plant at Longford in the Australian state of Victoria's Gippsland region. On 25 September 1998, an explosion took place at the plant, killing two workers and injuring eight. Gas supplies to the state of Victoria were severely affected for two weeks.
Context
In 1998, the Longford gas plant was owned by a joint partnership between Esso and BHP. Esso was responsible for the operation of the plant. Esso was a wholly owned subsidiary of US based company Exxon, which has since merged with Mobil, becoming Exxon Mobil. BHP has since merged with UK based Billiton becoming BHP Billiton
Built in 1969, the plant at Longford is the onshore receiving point for oil and natural gas output from production platforms in Bass Strait. The Longford Gas Plant Complex consists of three gas processing plants and one crude oil stabilisation plant. It was the primary provider of gas to Victoria, and provided some supply to New South Wales.
Normal processing procedure
The feed from the Bass Strait platforms consists of LPG, liquid hydrocarbons, water (H2O) and hydrogen sulfide (H2S). The water and H2S are removed before reaching the plant, leaving a vapourous mixture of LPG and hydrocarbons. The LPG is further extracted by means of a shell and tube heat exchanger, in which heated "lean oil" and cold "rich oil" (oil which has absorbed LPG) are pumped into the exchanger, cooling the lean oil and heating the rich oil.
Explosion at Longford
During the morning of Friday 25 September 1998, a pump supplying heated lean oil to heat exchanger GP905 in Gas Plant No. 1 went offline for four hours, due to an increase in flow from the Marlin Gas Field which caused an overflow of condensate in the absorber.
The normal operating temperature of the heat exchanger was 285 °C. Due to the failure of the lean oil pump, GP905 was operating at -48 °C. Ice had formed on the unit, and it was decided to resume pumping heated lean oil in to thaw it. When the lean oil pump resumed operation, it pumped oil into the heat exchanger at 230 °C - the temperature differential caused a brittle fracture in the exchanger (GP905) at 12.26pm.
About 10 metric tonnes of hydrocarbon vapour were immediately vented from the rupture. A vapour cloud formed and drifted downwind. When it reached a set of heaters 170 metres away, it ignited. This caused a deflagration (a burning vapour cloud). The flame front burnt its way through the vapour cloud, without causing an explosion. When the flamefront reached the rupture in the heat exchanger, a fierce jet fire developed that lasted for two days.
Further ruptures and fires caused by the initial blast caused further venting and more explosions. Two plant workers - Peter Wilson and John Lowery - died in the conflagration, and eight other workers were injured.
Aftermath
The fire at the plant was not extinguished until two days later. The Longford plant was shut down immediately, and the state of Victoria was left without its primary gas supplier. Within days, the Victorian Energy Network Corporation shut down the state's entire gas supply. The sudden crisis was devestating to Victoria's economy, crippling industry and the commercial sector (in particular, the hospitality industry which relied on LP gas for cooking). Loss to industry during the crisis was estimated at around AUD$1.3 billion.
LP gas is also widely used residentially in Victoria for hot water and gas heating, and Victorians endured many weeks of cold showers and chilly nights.
Gas supplies to Victoria were 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.
Royal Commission
A Royal Commission was called into the explosion at Longford, headed by former High Court judge Daryl Dawson. The 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 initially blamed the accident on worker negligence, in particular Jim Ward, one of the panel workers on duty on the day of the explosion. The findings of the Royal Commission, however, cleared Ward of any negligence or wrong-doing. Instead, the Commission found Esso fully responsible for the accident:
- The causes of the accident on 25 September 1998 amounted to a failure to provide and maintain so far as practicable a working environment that was safe and without risks to health. This constituted a breach or breaches of Section 21 of the Occupational Health and Safety Act 1985.
Other findings of the Royal Commission included:
- the Longford plant was poorly designed, and made isolation of dangerous vapours and materials very difficult;
- inadequate training of personnel in normal operating procedures of a hazardous process;
- excessive alarm and warning systems had caused workers to become desensitised to possible hazardous occurrences;
- the relocation of plant engineers to Melbourne had reduced the quality of supervision at the plant;
- poor communication between shifts meant that the pump shutdown was not communicated to the following shift.
Certain managerial shortcomings were also identified:
- the company had neglected to commission a HAZOP (HAZard and OPerability) analysis of the heat exchange system, which would almost certainly have highlighted the risk of tank rupture caused by sudden temperature change;
- Esso's two-tiered reporting system (from operators to supervisors to management) meant that certain warning signs such as a previous similar incident (on 28 August) were not reported to the appropriate parties;
- the company's "safety culture" was more oriented towards preventing lost time due to accidents or injuries, rather than protection of workers and their health.
Legal ramifications
Esso was taken to the Supreme Court of Victoria by the WorkCover Authority. Justice Philip Cummins found the company guilty of eleven breaches of the Occupational Health and Safety Act 1985, and fined them a record $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 between on 4 September 2002, and was eventually settled in December 2004 when Esso was ordered to pay $32.5million to businesses which suffered property damage as a result of the incident.
Victoria (and several other Australian states) amended their laws regarding plant safety for hazardous facilities and public utilities.
References
- Hopkins, Andrew. Lessons From Longford: The Esso Gas Plant Explosion, CCH Australia Limited, 2000. ISBN 1864684224
External links
- Victorian Coroner's Report into the Longford Gas Explosion PDF Document
- Implications of the Esso Longford verdicts on the engineering profession Microsoft Word Document