Energy multinational ExxonMobil has been fined £2.8m for failing to report greenhouse gas emissions from its chemical plant in Scotland.

It is the largest fine for an environmental offence in British history.

The Scottish Environment Protection Agency (Sepa) hit the company with the fine in 2010/11 after it did not report 33,000 tonnes of carbon dioxide emissions from its Mossmorran ethylene plant in Fife.

The fine was not publicised by Sepa at the time, and only came to light in a report published last week, which revealed ExxonMobil identified sources of carbon dioxide that had not been reported in its return for 2008.

EU laws place strict rules on companies for accurately reporting emissions. Firms found to have misreported their greenhouse gas emissions can be fined 100 euro or £83 for every tonne they miss.

The money has been passed to the Scottish Government to fund a series of environmental projects.

ExxonMobil said it ‘regrets the errors’ in its reporting and accepted the need for more action to tackle rising emissions. Spokesperson Dan Worrall told STV News: “ExxonMobil Chemical Limited and Esso Petroleum Company Limited have each identified and reported inaccuracies in the reporting of CO2 emissions under the EU Emissions Trading Scheme, covering emissions in 2008. In both cases these inaccuracies were identified by ExxonMobil’s internal systems and were immediately reported to the regulator by the company. We have now fully reviewed and improved our procedures at both sites to address the issues we identified.

“Information on the inaccuracy identified at its Fife Ethylene Plant (FEP) was immediately provided by ExxonMobil Chemical Limited to the Scottish Environment Protection Agency and represented some 4.7% of the site total. The root cause of the under-reporting at FEP was incorrect mapping of routings within facilities.

“In the past two years ExxonMobil Chemical Limited has made significant investments at Fife to reduce NOx and CO2 emissions. ExxonMobil regrets the errors relating to the reporting of greenhouse gas emissions under the European Union Emissions Trading System. ExxonMobil believes that the risks posed by rising greenhouse gas emissions to society are serious enough to warrant action – by individuals, by businesses and society.”

Scottish Ministers accepted there was no intention to mislead on the part of ExxonMobil. A Scottish Government spokesperson said: "The Scottish Government is pleased that ExxonMobil Chemical Ltd acknowledged its under-reporting in the EU Emissions Trading Scheme and so reported its failure to Sepa. Ministers accept that there was no intention to mislead and it was a genuine error. There are mandatory penalties in such cases and Sepa has done its job in applying them."

WWF Scotland's director Richard Dixon welcomed the fine, saying: "The whole point of the European trading scheme is to limit the total climate pollution coming from industry, so it is quite right that fines should be high for those who fail to comply. You would assume that Exxon are now very careful to report the right data but this massive fine is a big message to others to get it right."

According to Sepa, four other companies have also been penalised for underestimating greenhouse gas emissions from plants in Scotland. They are the Dow Chemical Company for its Grangemouth plant, Tennent Caledonian in Glasgow, Pernod Ricard in Glasgow, and FMC BioPolymer in Girvan.