The company suspended sales of its mid-grade and premium gasoline pending additional testing, the Chicago Tribune reported. BP announced Thursday that it believed problems at the Whiting terminal had been resolved.
A batch of 50,000 barrels of gas was sent to stations last week. The company said the fuel was blended with a "higher than normal level of polymeric residue."
"We're telling resellers to not sell premium and mid-grade in Chicagoland until we are 100 percent satisfied with the quality," Scott Dean, a company spokesman in Chicago, said.
Car owners who believe their vehicles were damaged by the gas can file claims with the company.