A petrochemical plant has been fined after ethylene, a flammable gas was released from a cracked pipe at the Ethylene Plant. On May 2, 2017, approximately 17 tons of ethylene were released from the pipe. This leak precipitated the formation of a flammable gas cloud of around 2,295,453 cubic ft. The gas cloud was seen to move through a congested area of the plant reaching ground level. An investigation by the Health and Safety Executive (HSE) identified that the immediate cause of an unplanned shutdown on the compressor was due to a ‘non-routine maintenance activity related to the changeover of a redundant electronic control card in the compressor anti-surge system.
The line should have been designed for all potential operating conditions and should not have failed as a result of the rapid opening of the valve and the sudden inrush of hot gas. The section that failed had been wrongly identified as not high-risk and therefore not subjected to insulation strips as part of a regular inspection program.
This allowed a process called chloride-induced stress load corrosion cracking to occur.
The facility pleaded guilty to breaching Regulation 5(1) of the Control of Major Accident Hazards Regulations 2015 and section 33(1) of the Health and Safety at Work etc. Act 1974. They were fined £400,000.