Exxon Mobil has been ordered to pay $6.1 million (£4 million) after failing to adhere to pollution regulations, it has been reported
The fine was issued after the firm was found to be in violation of rules introduced in 2005.
It was alleged that the company failed to live up to a pledge it made in accordance with the regulations to spend $571 million on equipment designed to cap pollution at seven of its plants.
A further $6.7 million was pledged to environmental community schemes.
Assistant attorney general Ronald Tenpas said: "The significant penalty in this case shows that noncompliance with settlement requirements will have serious consequences."
Meanwhile, Zul Tejpar, former vice president of contaminated soil firm Bennet Environment, this week pleaded guilty to participating in a plan to defraud the US Environmental Protection Agency.