The blast at Stanlow Manufacturing Complex in Ellesmere Port on 14 November 2013 caused more than 20m of damage. No-one was injured. Operators Essar Oil UK Ltd pleaded guilty at Liverpool Crown Court to an offence under the Health and Safety at Work Act. As well as the fine the firm was also ordered to pay almost 58,000 legal costs. 'Three key failings' The Health and Safety Executive, which brought the prosecution, said problems started during the start-up of its main distillation hoists 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 and started a number of fires, said the HSE. It was reported to the European Union as a major accident under schedule 7 of the Control of Major Accident Hazards (COMAH) Regulations 1999. An HSE investigation found Essar Oil UK Ltd failed to take all measures necessary to prevent or mitigate a major accident with three key failings: A safety critical valve was ordered and installed incorrectly and Essar failed to correctly validate its operation It failed to adequately assess the installation of a "safety critical trip" in missing it had a by-pass line Essar's policy was to isolate main fuel lines to the furnace but hydrocarbons entered the furnace via a secondary fuel line which had not been isolated when shut down An Essar spokesman said it accepted responsibility from the outset for the incident and that "measures were put in place to ensure it could not happen again". HSE principal inspector Joanne Eccles said after sentencing: "The industry should take notice of this case, there were no injuries but mistakes were made and could have been prevented."