Valero Energy Corp is the top US independent oil refiner
Valero Energy has announced it is permanently shutting down its oil refining plant in Delaware City, with the loss of 550 jobs.
The company says the closure of the 210,000 barrel a day plant will reduce operating expenses by $450m (£273m).
The plant is the largest refinery in the US to close this year. Valero also closed its Aruba refinery indefinitely in August.
The recession and slumping fuel demand have squeezed margins for US refiners.
The Delaware City refinery was losing the company $1m a day, according to Valero spokesman Bill Day.
Delaware is already wrestling with rising joblessness. The state's unemployment rate has jumped to 8.7% this year.