Another train carrying crude oil has derailed in the United States—this one erupting in flames in West Virginia. Yet it involved newer and supposedly tougher tank cars than are typically used in the rail industry, which is now facing stricter U.S. and Canadian safety rules.

More than 100 tank cars derailed Monday in a snowstorm in Mount Carbon, W.V., causing fires that continued to burn Tuesday. The accident threatened the local water supply and prompted the evacuation of hundreds of families. Officials are testing the water to determine if any of the oil, hauled from the Bakken shale fields in North Dakota, seeped into a tributary of the Kanawha River.

The train’s operator, CSX, said it was working to “contain oil found in a creek that runs parallel to CSX tracks.” Company spokesman Gary Sease said “the cause of of the derailment is under investigation.”

CSX also said that all the oil tank cars on the 109-car train were the CPC-1232 model, designed to be tougher and less prone to puncture than the most frequently used one—the DOT 111. Sease said the cars, owned by leasing companies, meet current federal rules but declined to say whether they would also meet proposed stricter standards.

This newer CPC-1232 model was also involved in an oil train derailment along the same line in April in Lynchburg, Va., that leaked crude into the James River. (See related post: “Oil Train Derails in Lynchburg.”)

The latest derailment, in a small town 33 miles (54 kilometers) southeast of Charleston, is the second major oil-train accident within a week. On Feb. 13, a Canadian National Railways train from Alberta’s oil sands derailed in a wooded area of northern Ontario.

The surging amount of oil moved by rail in North America has led to a spate of derailments, including a July 2013 tragedy that killed 47 people in the Quebec town of Lac-Mégantic. The tank cars that derailed at Lac-Mégantic lacked puncture-resistant steel jackets, thermal insulation, and heavy steel shields that could have lessened the destruction.

As a result, U.S. and Canadian regulators have since proposed stricter rules for rail cars transporting flammable fuels. In July, the Obama administration proposed speed limits for trains carrying these fuels, tougher braking requirements, and new design standards for rail cars. It called for the phaseout, in two years, of the DOT 111 unless retrofitted to comply with the new standards. (See related stories: “As Fiery Accidents Pile Up, U.S. Proposes New Rules for Oil Trains” and “New Oil Train Safety Rules Divide Industry.”)

“We need a new world order” for transporting fuel by rail, U.S. Transportation Secretary Anthony Foxx said last year in announcing the proposal, which now faces review by the White House’s Office of Management and Budget. He said DOT testing found that oil produced in the Bakken shale region of North Dakota and Montana, compared with other crudes, “is on the high end of volatility” and sometimes improperly classified by shippers as less flammable than it is.

A DOT report, released last year, said Bakken crude shipments travel, on average, more than 1,000 miles to coastal refineries. “There is an increased risk of a significant incident involving this material,” the report says.