Gas prices hit a high for the year on Labor Day as the effects of Harvey continued to shut in refineries.

As of Monday the nationwide average for a gallon of gas averaged $2.638, according to the AAA. That’s up from $2.45 on Thursday.

Gas prices are expected to decline by mid to late September because early reports do not show significant damage to refineries in Corpus Christi and Houston, said Jeanette Casselano, AAA spokeswoman, in a statement Thursday.

Phillips 66 said Monday hundreds of workers were at its Sweeney Refinery assessing the damage and repairing equipment. Its Lake Charles and Alliance refineries continue to operate as do the Beaumont and Freeport terminals.

Exxon Mobil said Sunday it’s making progress on restarting its Baytown refinery and chemical plant, which was spared significant damage from Harvey. The company’s Beaumont refinery is flooded and remained shut.

And Colonial Pipeline, which operates a key pipeline that runs from Houston to New York, said Sunday it may restart the transportation of distillates between Houston and Hebert, Texas, on Monday and of gasoline Tuesday.

Officials from Motiva, which operates the nation’s largest refiner in Port Arthur, Texas, didn’t immediately reply to messages.