WASHINGTON — A week after an oil-tanker train exploded in the Quebec town of Lac-Megantic, Quebec, leaving as many as 60 people presumed dead or missing, Maine U.S. Reps. Chellie Pingree and Mike Michaud on Thursday called for a federal investigation into the safety of the infrastructure used to transport crude oil and gas by rail through Maine.

The train that crashed in Quebec was carrying about 50,000 barrels of crude from North Dakota’s Bakken shale development to Irving Oil’s plant in Saint John, New Brunswick, Reuters reported. That plant processes an average of 300,000 barrels of oil per day.

In a letter to the National Transportation Safety Board, the Federal Railroad Administration and the U.S. Department of Transportation, Michaud and Pingree wrote that “a full accounting of the vulnerabilities of the existing infrastructure” is necessary. Maine’s two U.S. House representatives also asked that the government identify and quickly address any safety issues.

“The route of the Montreal, Maine and Atlantic Railway train that derailed in Lac-Megantic would have taken it directly through Maine and into New Brunswick,” they wrote. “Other trains routinely transport crude oil and other hazardous materials through southern Maine and into Canada.”

On Tuesday, Maine Gov. Paul LePage issued an executive order directing the state’s Department of Transportation to review the safety of freight rail transportation in Maine. Democrats in the Legislature also called for a review of the state’s rail system, with an eye toward implementing measures that would improve safety standards.

In the last year, crude oil shipments through Maine have increased 15 times, from 2,000 barrels per day to nearly 30,000 barrels per day crossing into Maine by rail in March, according to Pingree and Michaud.

“In addition, there have been three derailments of trains carrying hazardous materials in Maine during just the last six months,” they wrote, in calling for a new federal probe of rail transport of crude oil.

The Transportation Safety Board of Canada is investigating the July 6 explosion in Lac-Megantic. So far, the investigation has focused on the train’s hand brakes.