The U.S. attorney's office in Los Angeles has filed felony criminal charges against Phillips 66, accusing the company's Carson refinery of dumping tens of thousands of gallons of oil and grease into the county sewer system.

Phillips 66, the Houston-based oil and gas company, is facing federal charges for allegedly dumping hundreds of thousands of gallons of heavily polluted wastewater into the Los Angeles County sewer system.

A grand jury handed down a six-count indictment Wednesday, alleging the company's Carson refinery twice released non-compliant wastewater into the sewers and then failed to alert