Energy giant ExxonMobil has been fined £267,000 after five leaks of highly flammable hydrocarbons at its former ethylene plant in Scotland.
Health and Safety Executive (HSE) inspectors said what they found at the Mossmorran plant in Fife “beggars belief” and that it was down to good luck that none of the leaks resulted in a “catastrophic event”.
Investigation findings
HSE inspectors first discovered a leak when they visited the plant for a routine inspection on May 21 2019 and noticed a strong smell of dimethyl sulphide (DMS), a highly flammable liquid that irritates skin and eyes and is harmful if swallowed.
An investigation launched by HSE found that there had been an earlier leak from the same pipe in February the previous year, and another on a different pipe elsewhere on the site in December 2018.
As investigations continued, two more leaks were discovered, one on June 29 and another in September 2019.
Cause and court action
All five leaks were caused by corrosion under insulation (CUI) which happens when water gets beneath insulation used to stop pipes from freezing, and corrodes the pipe underneath.
Inspectors found that two of the leaks went on for about four months and that the company’s inspection system was not fit for purpose at the plant, where production ended in February this year.
HSE said that ExxonMobil Chemical Limited was fined £267,000 after admitting breaching the Health and Safety Act 1974 and one of the Provision and Use of Work Equipment Regulations 1998, during a hearing at Kirkcaldy Sheriff Court on Tuesday.
Reaction and response
HSE inspector Lindsey Stein said: “At a site run by one of the biggest energy companies in the world, subject to the strictest controls, and processing high volumes of hazardous material, what our inspectors found beggars belief.
“The failure of ExxonMobil to properly inspect insulated pipework led to five separate leaks of highly flammable hydrocarbons, and while none of these leaks resulted in a catastrophic event, this was down to good fortune rather than good management.
“The arrangements in place to detect and prevent corrosion were woefully inadequate, and the consequences could have been far more serious.
“Systematic risk management isn’t just best practice, it’s a legal duty, precisely because these are high-hazard operations where the margin for error is minimal.
“In its simplest terms, process safety is about keeping hazardous substances where they belong: inside the pipes, not in the atmosphere.
“Once we stepped in, the operator was able to identify and fix problems quickly and effectively. That tells you everything you need to know: the measures needed to prevent these leaks were reasonably practicable all along, and they should have been in place long before HSE was forced to intervene.”
HSE inspectors found that one of the leaks went on for six weeks and another for two weeks, while no timeframe was specified for the final leak.
The Fife Ethylene Plant was classed as an upper tier control of major accident hazards (COMAH) establishment due to the volume of hazardous substances on site and the risk they posed to people and the environment.
HSE said the plant was therefore subject to the strictest controls because of the potential that health and safety failings could have catastrophic consequences.
An ExxonMobil Chemical Ltd spokesperson said: “We have accepted responsibility and resolved a matter relating to historical corrosion under insulation issues at Fife Ethylene Plant between 2018 and 2019.
“No workers, contractors or members of the public were put at risk, and the court held that no hazard was created and no actual harm was caused.
“We co-operated fully with the HSE throughout its investigation, including complying with all notices served, and commissioned an independent assessment.
“We accept full responsibility for the failures identified and have since made significant changes to how we inspect and manage corrosion risk across our operations.
“At the time of the incidents, the Fife Ethylene Plant organisation was moving to a revised and improved inspection methodology and this was successfully implemented together with a special programme to address legacy challenges.”
