On 25 September 1998 a catastrophic accident occurred at the Esso natural gas plant in Longford, Victoria, Australia.

[1] A pressure vessel ruptured resulting in a serious jet fire, which escalated to a conflagration extending to a large part of the plant.

[4] The Victorian state government established the Longford Royal Commission to publicly investigate the causes of the accident.

[7] This occurred in two absorbers (working in a parallel configuration), large vertical pressure vessels in which chilled raw natural gas rose up from the bottom, on its way up shed heavier components (ethane, propane and butane) against the falling stream of lean oil and finally left the vessel at the top as methane.

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.

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 −48 °C (−54 °F).

[17] 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.

[17][21] 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.

The resulting gas supply shortage was devastating to Victoria's economy, crippling industry and the commercial sector.

This was the first time a royal commission was called for an industrial accident in the state of Victoria since the collapse of the West Gate Bridge in Melbourne in 1970.

[30][25] Points of interest and lessons learned from Longford include aspects such as: Certain managerial shortcomings were also identified: It has been argued that Esso's safety culture was too focused on lost-time incidents of an eminently occupational safety nature and was less concerned about safe plant maintenance and operations, an attitude that may ultimately have led to the major fire.

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.

[45][46][47] 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.

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.