Once a day, a train carrying crude oil from North Dakota’s Bakken oil fields rumbles through Bismarck, N.D., just a stone’s throw from a downtown park.

The Bakken fields produce more than 1 million barrels of oil a day, making the state the nation’s second-largest oil producer after Texas. But a dearth of pipelines means that most of that oil leaves the state by train — trains that run next to homes and through downtowns.

After several fiery accidents, oil companies are under pressure to make their oil less explosive before loading it onto rail cars. But oil companies say rules requiring those modifications will create more problems than they solve.

The trains passing through Bismarck worry Lynn Wolff, an activist with the environmental group Dakota Resource Council. “Last December we got the wake-up call,” he says. “That was the explosion and derailment of an oil train in Casselton, N.D.”

Wolff is referring to a crash in farmland just outside the small town of Casselton. No one was hurt, but the crash could have been deadly had it happened in town.

This summer, Bismarck officials ran through a simulated oil train derailment, with responders operating on the assumption that some of the town’s buildings would be devastated or destroyed, says Gary Stockert, Bismarck’s emergency manager. “We exercised with the assumption that we had over 60 or 70 casualties.”

Around the country, other cities and towns with oil train traffic are preparing for similar disasters.

In neighboring Minnesota, Gov. Mark Dayton “is concerned primarily about the safety of people along oil train routes, and in particular about the fact that this is a very volatile oil,” says Dave Christianson, an official with the Minnesota Department of Transportation.

Dayton has joined activists in asking North Dakota to force oil companies to “stabilize” the oil — to make it less explosive by separating out the flammable liquids.

Last month, North Dakota Gov. Jack Dalrymple convened a public hearing on the idea. Keith Lilie, an operations and maintenance manager for Statoil, which has a big presence in the Bakken, testified in front of a room full of oilmen in suits and cowboy boots who came to the hearing from places like Oklahoma City and Houston.

Lilie said he opposes having to build expensive tanks to heat the oil and separate out flammable liquids, like butane.

“Statoil believes the current conditioning of crude oil is sufficient for safely transporting Bakken crude oil by truck, rail and pipeline,” he said.

Eric Bayes, general manager of Oasis Petroleum’s operations in the Bakken, also testified. He asked what companies are supposed to do with those explosive liquids once they’re separated from the oil.

The stabilization process, he says, would “create another product stream you have no infrastructure in place for.”

But energy economist Philip Verleger, says the resistance is about money. “The industry never wants to take steps which increase the cost of production, even if it’s in the best interests of everybody,” he says.

Verleger says the opposition to proposed safety rules is short-sighted, and that the industry could actually hurt itself if there’s another serious incident. “I think the movement of crude oil by rail is one accident away from being terminated,” Verleger says.

Activist Lynn Wolff supports new rules that would make the oil less explosive, and says such regulation would protect people beyond North Dakota. “These bomb trains have been in Virginia and Alabama and blown up there as well,” he says.

Federal officials in Washington are also considering ways to make oil trains safer, such as strengthening tank cars.

As for making the oil leaving the Bakken less flammable, officials in North Dakota say they’ll make a decision by the end of the year.

This story was reported with Inside Energy, a public media collaboration focusing on America’s energy issues.