Sunoco Inc. (SUN) reported $34 million in administrative charges primarily related to severance costs for the first quarter, and says it may accrue similar charges later in the year.

Independent refiner Sunoco began a business improvement plan in 2008, focused upon reducing costs. In the first phase of this plan, Sunoco reviewed some of its refineries, with aid from McKinsey & Co. consultants. Sunoco will now use internal teams to review the rest of its refineries and chemical plants.

"Because we have just started the work in the other plants we're not really in a position to determine the size," Chief Executive Lynn Elsenhans told analysts on a conference call, when asked about future costs associated with layoffs. "When we know what it is we will disclose it," Elsenhans said.

The $34 million charge in the first quarter included a $4 million after-tax charge for a contract loss, employee severance and other exit costs in connection with the shutdown of a chemical plant in Bayport, Texas. The company has not announced any other plans to close production facilities.

-By Jessica Resnick-Ault, Dow Jones Newswires; 201-938-4435; jessica.resnick-ault@dowjones.com