Essar Oil UK has been fined £1.65 million after an explosion at its Stanlow refinery in Ellesmere Port.
There were no injuries at the incident in Cheshire, but the blast in the early hours of November 14, 2013, caused internal structures to collapse, causing damage worth more than £20 million, Liverpool Crown Court heard.
Problems started at the site during the start-up of its main distillation unit, when extremely flammable hydrocarbons were allowed to enter an unignited furnace.
The heat from another furnace nearby triggered the explosion which destroyed the furnace, starting a number of fires that the fire service had to bring under control.
The incident was reported to the European Union as a major accident under schedule 7 of the Control of Major Accident Hazards (COMAH) Regulations 1999.
A Health and Safety Executive (HSE) investigation found that Essar Oil UK Ltd failed to take all measures necessary to prevent or mitigate a major accident.
Some of the failings it identified were that a safety critical valve was ordered and installed incorrectly and Essar failed to correctly validate its operation.
The company was also found to have failed to adequately assess the installation of a new safety critical trip as they failed to recognise the system had a by-pass line which defeated the trip’s operation.
The HSE found that Essar’s policy was to isolate main fuel lines to the furnace however, the hydrocarbons entered the furnace via a secondary fuel line which had not been isolated when shut down.
Essar Oil (UK) Ltd of the Stanlow Manufacturing Complex, Ellesmere Port, pleaded guilty to breaching Regulation 4 of the Control of Major Hazards Regulations 1999 and was fined £1,650,000 with costs of £57,644.80.
An Essar spokesman said “We made clear to the courts from the outset that we accepted responsibility for the incident.
“We take this matter very seriously. Following the incident in November 2013, measures were put in place to ensure it could not happen again.
“No one at Stanlow was hurt and there were no effects on the general public off-site.”