NEW YORK » Chevron Corp., which operates one of two refineries in Hawaii, said it plans to shrink its refining business in a move that will cut jobs throughout the company.

Lloyd Avram, manager of media relations for Chevron, said no decision has been made yet regarding the Hawaii plant.

“;Our Hawaii refinery has been undergoing a study for some months to determine options for the facility,”; Avram said yesterday. “;The study continues with no decisions yet made.”;

The Chevron facility at Campbell Industrial Park in Kapolei has a refining capacity of 54,000 barrels a day. The largest refinery in the state, operated by Tesoro Corp., has a capacity of 95,000 barrels a day.

“;We will have more information to share on this new structure in March,”; Avram said.

Chevron hasn't yet decided how many of its employees will be affected and whether the cuts will be concentrated in the U.S.

Avram said the company is reviewing its entire downstream operation.

Chevron's refining business will be “;a less complex and smaller organization that will require fewer positions,”; Avram said.

Petroleum refineries have struggled to make money as oil prices doubled from early 2009 while demand for gasoline and jet fuel dropped. Independent refiners shuttered some of their operations last year, and others are running at the lowest levels since 1991.

Chevron, the second-largest U.S. oil company, has warned investors that profits will shrink in the fourth quarter, primarily because of its refining business.

According to an interim report released earlier this month, Chevron said fourth-quarter profit margins were about 39 percent lower than last year for its Gulf Coast refineries. They were 59 percent lower in Singapore and 45 percent lower in Europe.

Chevron's refineries had losses of more than $600,000 a day during the final three months of 2009 as crude costs rose faster than fuel prices, eroding profit margins from processing oil into gasoline and diesel, Paul Sankey, an analyst at Deutsche Bank, said last week.

Avram said the company hasn't decided when to announce job cuts. However, changes to the company's refining business are expected to be in place by the third quarter, he said.

“;This is really consistent with what's been going on in the rest of the industry,”; said Jason Gammel, an analyst at Macquarie Securities USA Inc. in New York. “;Everyone is looking at taking capacity out of the system to cope with extremely poor margins.”;