Sunoco is idling a refinery in suburban Philadelphia and says about 490 layoffs are expected.
Sunoco CEO Lynn Elsenhans said Thursday deteriorating market conditions are forcing the move at the facility in Marcus Hook.
The Philadelphia-based fuel company announced in September it was getting out of the refining business. It said two area facilities would be idled by next July if they couldn't be sold.
But the CEO says in a statement the Marcus Hook refinery is being idled immediately because of the weak outlook for motor fuel demand and refining margins.
Sunoco says about 100 employees will be placed elsewhere within the company. Sunoco's refinery in Philadelphia continues to operate.