The drop in oil prices has taken a toll on profit at Sunoco Inc. So did the May fire at its Marcus Hook refinery.

The Philadelphia oil refiner and marketer yesterday reported a net loss of $55 million, or 47 cents a diluted share, in the second quarter. Sunoco reported net income of $82 million a year earlier, or 70 cents a share.

Sunoco wrote off $19 million - $14 million after taxes - after shutting down its fire-damaged ethylene complex at the Marcus Hook refinery. The company decided to close the unit because of the depressed market for ethylene, used in manufacturing plastics and other chemicals.

Excluding special items, Sunoco reported a loss of $31 million, or 27 cents a diluted share, compared with income a year earlier of $61 million, or 51 cents a share.

Analysts had been expecting a loss. Crude oil was trading for about $60 a barrel in the second quarter, roughly half the price of a year ago.

"During the second quarter, refining and chemicals results were impacted by weak demand and rising crude prices, but our other businesses continued to generate steady earnings," said Lynn Elsenhans, Sunoco's chief executive officer.

She said that earnings from non-refining businesses - retail marketing, coke production, and pipeline operations - improved to $78 million in the second quarter, up from $47 million a year earlier.

"We continue to expect a challenging market for petroleum and chemical products due to ongoing economic weakness and additional global supply," Elsenhans said. She said the company continued to make progress to reduce operating costs.

Sunoco announced its earnings after markets closed. Its shares closed at $26.40, up 47 cents, or 1.81 percent.

But in after-hours trading, its shares were down about 4 percent.

Contact staff writer Andrew Maykuth at 215-854-2947 or amaykuth@phillynews.com.