ExxonMobil fined £267,000 over chemical leaks at Mossmorran

Testing of the piping, including X-ray imaging, later found it had “corroded below its safe minimum thickness”.

Inspector Lindsey Stein said the firm’s inaction in dealing with the leaks “beggared belief”.

Stein said: “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.”

The HSE noted the company had since made the required repairs.

Stein added: “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.”