WILMINGTON, Del. -- Refineries from New Mexico to New Jersey are under severe economic pressure because of falling demand for fuel, with a number of facilities shutting down in recent months, said the Associated Press. Valero Energy Corp., which shuttered a major refinery over the summer, said Friday it would permanently close its Delaware City oil refinery and layoff 550 workers. It is the largest U.S. refinery to close this year.

Refineries in the Northeast are particularly vulnerable because many are older, operate less efficiently and must compete with gasoline imported from Europe.

The Delaware City refinery, where workers were notified of the closing Friday, lost about $1 million every day this year, said Valero spokesperson Bill Day.

Demand for fuel has been falling for some time and the recession has made things worse, squeezing profit margins for refiners everywhere.

Refiners are pulling capacity offline and are now operating at levels more consistent with the aftermath of a hurricane in the Gulf of Mexico.

El Paso, Texas-based Western Refining Inc. announced earlier this month that it would close its Bloomfield, N.M., facility, putting 100 people out of work.

Valero, based in San Antonio, said in September that it would idle two units in Delaware City, cutting about 150 jobs. Last month, the company said it would cut another 100 jobs at its Paulsboro, N.J. refinery by the end of the year. The Paulsboro announcement came just days after Sunoco Inc. said it would indefinitely idle its Eagle Point facility, which employs about 400 workers in New Jersey.

In June Valero shut its refinery in Aruba, which had a capacity of about 275,000 barrels a day. The Delaware City refinery had a capacity of 210,00 barrels a day.

Valero chairman and CEO Bill Klesse said the company had sought a buyer for the Delaware facility, but found no takers. "At this point, we have exhausted all viable options," he said.