The operators of the Fife Ethylene Plant at Mossmorran could still be prosecuted over recent flaring incidents which have caused misery for communities in central Fife.
The information was revealed in the final warning letters issued by environmental regulator SEPA to Shell and ExxonMobil back in April.
They have only now been made public.
Setting out the legislation breach which brought about the final warning, both state that any further/continued contravention of the legislation was likely to result in enforcement action being taken by SEPA.
They continue: “Such enforcement action could include the submission of a report to the Procurator Fiscal recommending prosecution”.
Mid Scotland Fife Green MSP Mark Ruskell has said the ongoing investigations into the plant needed to be concluded urgently and he expected legal action to follow.
Since last June’s incident there have been three incidents of flaring.
Mr Ruskell said: “I’ve been asking for some time now for these final warning letters to be published, and the information is very revealing.
“It clearly states we could soon be seeing legal action taken against the plant operators, and this could include holding them to account over last summer’s flaring, as well as the multiple incidents that have happened since then.”
He added:“The Mossmorran Action Group have been compiling examples of the social impacts of flaring in communities around the plant, and the results are consistently unacceptable.
“I’ve recently had a productive meeting with the public health minister too to urge the Scottish Government to investigate flaring as a public health issue.
“But all this action is meaningless if we don’t also see basic legal enforcement of our environmental and industrial laws.”
Mr Ruskell is meeting with the plant operators and SEPA later this week.
“And I’ll be making it clear that the investigations over the more recent incidents need to be concluded urgently.
“Nothing less than legal action is acceptable now.”