An oil company has been ordered to pay a fine worth more than £497,000 for environmental offences.
Essar Oil UK has also been fined £40,000 in relation to two separate incidents which occurred in 2012.
According to the Environment Agency (EA), the roof of an oil storage tank failed under pressure at Stanlow Oil Refinery in Ellesmere Port in July 2012.
It released steam and oil into the atmosphere and fine droplets of oil were reported in an area of more than five kilometres.
Another incident occurred in August when around five tonnes of oil entered the Manchester Ship Canal following failures in the operation of Essar’s effluent management system.
Nigel Glasgow from the EA said: “These pollution incidents were significant events resulting in large numbers of complaints and clean up costs for Essar. Permit breaches of this nature are taken seriously by regulators and the courts. Since these incidents the Environment Agency has worked closely with Essar who have improved their environmental performance and we look forward to their continued co-operation.”