Petrochemical giant Ineos has been fined £400,000 after an employee was permanently scarred when his leg became submerged in a caustic solution.

The company was handed the fine after the 47-year-old worker’s leg plunged into a sump which contained the solution on November 25, 2019 at its site in Grangemouth, Falkirk.

Ineos pleaded guilty to an offence under the Health and Safety at Work etc. Act 1974 and was fined £400,000 at Falkirk Sheriff Court on Friday, the Health and Safety Executive (HSE) said.

The worker, who has not been named, ended up in the sump, a low space that collects waste such as water and chemicals, due to inadequate grating and sustained severe burn injuries, HSE said.

The sump had needed emptying as its contents had reached the high-level design threshold the day before on November 24.

The worker had laid out various hoses to prepare for emptying the sump and stepped on to the corner of the grating with his right leg.

But the grating gave way and his leg plunged into the sump, becoming saturated with the caustic solution.

It was submerged in the solution for three seconds before the man pulled himself clear. He was later treated at the burns unit at St John’s Hospital in Livingston, West Lothian.

The man sustained permanent scarring to his right leg and was in pain for four weeks following the incident. He returned to work in December 2019.

An HSE investigation found Ineos had failed to undertake a risk assessment of the work involved.

There was also no safe system of work in place. The grating was not secured and there were no barriers in place to prevent a fall into the sump.

HSE inspector Lindsey Stein said: “The duties on employers to undertake a suitable and sufficient assessment of risks and to provide a safe system of work are absolute within health and safety legislation and well understood.

“The dangerous properties of caustic are widely known and this incident could so easily have been avoided with the implementation of straightforward control measures identified through assessment.”

Debbie Carroll, who leads on health and safety investigations for the Crown Office and Procurator Fiscal Service, said: “This accident could have been avoided had the risks been recognised and appropriate systems of work put in place in ensuring workers were protected from harm when working in this area.

“Ineos Chemicals Grangemouth Limited’s failure to assess the risks posed resulted in the severe injury and permanent disfigurement of one of their workers.

“This prosecution should remind duty holders that a failure to manage and implement effective measures can have serious consequences and they will be held accountable for this failure.”

Ineos has been contacted for comment.