May 6 (Reuters) - Marathon Petroleum ( MPC ) swung to

loss in the first quarter, the company reported on Tuesday, the

latest U.S. refiner hit by lower refining margins during a

period marked by elevated maintenance and turnaround activity

across the industry.

Net loss attributable to the company was $74 million, or 24

cents per share, for the three months ended March, compared to a

profit of $937 million, or $2.58 per share, a year earlier.