The derailments this week of two trains carrying crude oil have raised new questions about the adequacy of federal efforts to improve the safety of moving oil on tank cars from new North American wells to distant refineries.
A 100-car, southbound CSX train derailed Monday in a West Virginia river valley, destroying a home and possibly contaminating the water supply for downriver residents. A thundering fireball rose hundreds of feet above the community amid an intense winter storm.
As of 3 p.m. Eastern time, the fire was still burning, according to Lawrence Messina, the state's public safety spokesman.
"We hope the tanker fire will burn itself out by later this afternoon," he said.
Of the 26 tanker cars that derailed, 20 caught fire, Messina said. The massive blaze also knocked out power in the area.
On Sunday, an eastbound oil train derailed in Ontario, Canada, near the city of Timmins, engulfing seven cars in an intense fire and disrupting passenger service between Toronto and Winnipeg.
The most recent accidents follow a long string of crashes that have occurred amid an exponential increase in the amount of crude being transported by rail, as energy production booms across the U.S. and Canada.
Scrutiny of the rail industry began to intensify after the July 2013 accident in Lac-Megantic, Quebec, in which a train carrying 72 tank cars of crude crashed into the small Canadian town's center and killed 47 people. It was followed by derailments and fires in North Dakota, Alabama, Virginia and elsewhere.
Data compiled by the federal government and the petroleum industry show that there have been more than a dozen derailments of trains carrying either crude or ethanol since 2009, not including several that occurred in Canada.
The West Virginia accident occurred Monday during intense cold and heavy snow near Mount Carbon, where the CSX rail line winds through a narrow valley carved by the Kanawha River about 60 miles southeast of Charleston.
The train had 109 cars carrying oil from North Dakota to Yorktown, Va., CSX said. Messina said reports of tanker cars in the river were inaccurate, but officials do believe oil has leaked into the water, he said.
"However, the good news is that, to this point, the water treatment plant supply does not appear to have been affected," Messina said. "Tests have been negative for hydrocarbons."
After the derailment, when the fire was at its peak, 1,000 people were evacuated from the area. By Tuesday afternoon, that number shrunk to as many as 125 people who are now temporally displaced, Messina said.
"They will be allowed to return once the area is cleared and power has been restored," Messina said.
One house was destroyed by the fire, but no one has been injured.
The National Transportation Safety Board has increased its focus on oil tanker safety, and environmental groups are calling for tougher controls.
"Back-to-back fiery derailments involving crude oil trains should be an unmistakable wake-up call to our political leaders: Stop these dangerous oil trains and stop them now," said Mollie Matteson, a senior scientist with the Center for Biological Diversity.
The U.S. Department of Transportation responded last year, reducing speed limits in urban areas and calling for better brakes and stronger standards on rail tank cars so that they could withstand crashes without rupturing.
CSX said the latest West Virginia tank cars were a new version of the T-111 standard, known as a CPC-1232. The federal government authorized those upgraded tank cars in 2011, and an even newer and possibly tougher standard is expected to be unveiled later this year.
But it could be years before it has a measurable effect on safety, depending on how many of the existing 98,000 tank cars have to be retired or retrofitted.
Brigham McCown, former chief of the Pipeline and Hazardous Material Safety Administration, the federal agency that oversees tank car safety, said government needed to cut the number of derailments by such measures as improving brakes, including the introduction of electronically controlled brakes.
Current air brakes are applied sequentially on each rail car, meaning that it takes more than a minute for all the brakes to be applied on a 100-car oil train, he said.
"There are a lot of technical improvements we could be looking at, and I don't think we are," he said.
McCown said most of the derailments have occurred in extreme weather, when rain has washed out rail beds or when intense cold or heat distorts or weakens steel rails.
There is no time line for when the West Virginia derailment site will be cleared.