OTTAWA - A regulatory failure to distinguish between different types of crude — and to recognize the potentially explosive qualities of so-called shale oil — could cost lives in the future, a leading environmental group says.

Tanker cars that derailed and exploded early on July 6 in Lac-Megantic, Que., east of Montreal, were carrying oil from a large shale deposit in North Dakota known as the Bakken field.

Federal government regulation and safety standards do not distinguish between different types of crude oil — labelling all of them as Class 3 flammable liquids for transportation purposes, even though the chemical composition could make one type more explosive than another, said Keith Stewart of Greenpeace.

Stewart said it's still too early to say how much of a role the composition of the Bakken crude played in the disaster, which officials now say is believed to have killed some 47 people.

"We simply don't know enough at this point to say if the failure of regulation to keep up with new types of oil moving in new ways has cost lives in this tragic event, but we do know that it has the potential to do so in the future," said Stewart, who has been studying the dramatic increase in the use of railways to haul oil.

"Our safety regulations have failed to keep pace with the rapid increase in the transportation of new types of oil in new ways."

Bakken oil is extracted in drips and drops from deep layers of sedimentary rock, found mostly in North Dakota, Montana, Saskatchewan and Manitoba. The oil companies get at it through fracturing the shale around the pockets, a process known as fracking.

Some of it is known to contain hydrogen sulphide vapour, a flammable, corrosive, and highly explosive compound. Bakken oil in particular is known to contain high levels of flammable hydrogen sulphide gas.

Transportation Safety Board investigators confirmed Friday that they are testing oil and residue at the scene to determine what may have been present at the time of the disaster, although they refused to speculate on a possible role.

Transport Canada and Environment Canada were asked several questions about the distinction between different types of petroleum products, but no one was immediately available to respond.

The Canadian Association of Petroleum Producers declined to be interviewed.

The House of Commons transport committee is to be recalled from summer recess on Tuesday for emergency hearings on railway safety. New Democrat transportation critic Olivia Chow, who is deputy chair of the committee, persuaded three other MPs to support her bid for a meeting.

Not everyone is convinced that different types of crude oil require separate and distinct classifications as dangerous goods.

Railway analyst Chris Damas of BCMI Research said the composition of the oil is not a major safety concern, adding he believes that establishing separate regulations and rules for handling different types of crude would make little difference.

"It's already classified properly," Damas said Friday.

"For me the key thing is: We had a runaway train. We don't have a paucity of regulation on hazardous material. What we have, perhaps, is a paucity of regulations of trains carrying hazardous materials through populated areas."

Rail companies also don't have the obligation to discriminate between different types of cargo, he added.

But Greenpeace said railways should follow the example of Enbridge Inc., which refused to carry Bakken oil with extremely high levels of hydrogen sulfide in its pipelines.

"Enbridge gave one day notice before shutting their facilities to crude that they deemed to be dangerous, and we should expect no less from the rail companies," Stewart said.

"With this much money on the line, however, these kinds of safety decisions can't be left to individual companies. The bigger problem is that the Harper government has been fixated on boosting oil exports by any means necessary, that it has abandoned its responsibility to protect the safety of our communities and the environment."

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  • Work continues at the crash site of the train derailment and fire in Lac-Megantic, Que., on Tuesday, July 16, 2013, that left 37 people confirmed dead and another 13 missing and presumed dead.

  • Work continues at the crash site of the train derailment and fire Tuesday, July 16, 2013 in Lac-Megantic, Que. that left 37 people confirmed dead and another 13 missing and presumed dead.

  • Work continues at the crash site of the train derailment and fire Tuesday, July 16, 2013 in Lac-Megantic, Que. that left 37 people confirmed dead and another 13 missing and presumed dead.

  • A fireman walks through the debris as work continues at the crash site of the train derailment and fire Tuesday, July 16, 2013 in Lac-Megantic, Que. that left 37 people confirmed dead and another 13 missing and presumed dead.

  • A levelled building is seen in the foreground the day after a train derailed causing explosions of railway cars carrying crude oil Sunday, July 7, 2013 in Lac Megantic, Que.

  • Canadian Prime Minister Harper, right, surveys the scene Sunday, July 7, 2013 in Lac Megantic, Quebec, as firefighters continue to spray derailed tanker cars. A runaway train derailed Saturday causing explosions of railway cars carrying crude oil and destroyed part of the downtown area of Lac Megantic.

  • Prime Minister Harper, centre, talks with firefighters Sunday, July 7, 2013 in Lac Megantic, Quebec. A runaway train derailed Saturday exploding tanker cars carrying crude oil and destroying part of the downtown area of Lac Megantic.

  • Prime Minister Stepen Harperwaves to people as he visits the site Sunday, July 7, 2013 in Lac Megantic, Quebec, where a runaway train derailed Saturday. Tanker cars carrying oil exploded after the derailment and destroyed the business district in Lac Megantic.

  • Firefighters keep watering railway cars the day after a train derailed causing explosions of railway cars carrying crude oil Sunday, July 7, 2013 in Lac Megantic, Que.

  • The downtown of Lac Megantic, Que. is seen Sunday, July 7, 2013, the day after a train derailed causing explosions of railway cars carrying crude oil.