UPDATE 7-Sunoco refinery fire stokes U.S. gasoline price

(Recasts with Sunoco's latest statement)

By Erwin Seba

HOUSTON, May 18 (Reuters) - Sunoco Inc (SUN.N) said on Monday afternoon that a gasoline-producing fluidic catalytic cracking unit at its 178,000 barrel per day (bpd) Marcus Hook, Pennsylvania, refinery was shut following Sunday night's explosion in an ethylene unit.

The refinery's crude distillation unit was running at 85 percent of planned production levels, said Sunoco spokesman Thomas Golembeski as refinery firefighters continued to keep contained the blaze triggered by the blast.

The Sunday night blast and fire triggered a rally in gasoline prices on Monday. Gasoline futures on the New York Mercantile Exchange RBc1 rose 7.75 cents to settle at a seven-month high of $1.7581 a gallon, while heating oil HOc1 rose 5.69 cents to $1.4757.

The crude unit's throughput had been cut prior to Sunday's blast, Golembeski said, as Sunoco bucked up margins in the face of motor fuel demand cut by the recession. Sunoco's refineries' crude units were running at an average 78 percent prior to the blast, the company had said.

Assuming Marcus Hook's crude throughput was down by 78 percent before the blast, the refinery's oil intake could be down by as much as one-third to about 118,000 bpd after the explosion.

Air monitors set up around the refinery continue to show no threat to human health from the substances being burned in the blaze, he said.

Investigators from Sunoco, the U.S. Occupational Safety and Health Administration and the Delaware state fire marshal have begun interviewing unit operators.