ExxonMobil Chemical Limited has been fined £267,000 after five separate leaks of extremely flammable hydrocarbons were discovered at its Fife Ethylene Plant in Mossmorran, near Kirkcaldy. The incidents occurred between February 2018 and September 2019 and were traced to corrosion beneath pipe insulation. [press.hse.gov.uk], [hazardexonthenet.net]
The problem came to light during a routine inspection by the Health and Safety Executive (HSE) in May 2019 when inspectors detected a strong smell of dimethyl sulphide. Plant operators acknowledged that a leak involving dimethyl sulphide and ethane had been known about for around four months before action was taken. [press.hse.gov.uk], [hazardexonthenet.net]
The subsequent investigation uncovered five hydrocarbon leaks in total. One leak continued for approximately four months before being repaired, while another released an estimated 82 tonnes of hydrocarbons into the atmosphere over a six-week period. Investigators found that the company’s inspection regime for insulated pipework was inadequate and relied heavily on limited visual checks that often failed to identify corrosion. [hazardexonthenet.net], [press.hse.gov.uk]
At Kirkcaldy Sheriff Court on 25 August 2026, ExxonMobil Chemical Limited pleaded guilty to breaches of the Provision and Use of Work Equipment Regulations 1998 and the Health and Safety at Work etc Act 1974. The court imposed a £267,000 fine. [hazardexonthenet.net], [press.hse.gov.uk]
HSE inspector Lindsey Stein criticised the company’s maintenance arrangements, stating that the failures could have had far more serious consequences given the quantities of hazardous materials processed at the site. Despite the leaks, no catastrophic incident occurred and no actual harm was reported. [thechemica…gineer.com], [scotsman.com]
Shareable summary:
ExxonMobil has been fined £267,000 after five leaks of highly flammable hydrocarbons at its Mossmorran chemical plant in Fife. An HSE investigation found corroded pipework and inadequate inspection procedures were responsible for leaks that persisted for weeks and, in one case, months. The company pleaded guilty to safety breaches, with regulators warning the consequences could have been much more severe. [press.hse.gov.uk], [hazardexonthenet.net]
