LyondellBasell Industries NV’s Houston refinery reported emissions from a fluid catalytic cracker, a filing with the National Response Center showed.
The cause of a “relief valve releasing” was unknown, according to the filing. The plant can process 302,300 barrels of oil a day, according to data compiled by Bloomberg.
David Harpole, a refinery spokesman, didn’t immediately respond to an e-mail seeking comment.
U.S. refineries, producers and transmitters must notify the response center if they release hazardous substances in excess of reportable quantities, according to the Comprehensive Environmental Response, Compensation and Liability Act, commonly known as Superfund.
Bloomberg News couldn’t immediately verify that the information in the NRC filing was accurate.