One of the questions that the officials investigating the Lac Megantic train disaster will have to address is: Was oil deemed too dangerous for pipelines loaded onto rail cars instead?

It is still too early to know if the very high hydrogen sulfide and benzene levels in shale oil from the Bakken area of North Dakota played a role in this disaster, but it is clear that Canada’s regulatory regime hasn’t kept up with the risks posed by new types of crude oil moving in new ways.

Photo credit: Lac Megantic police

Since May, Greenpeace has been warning that the bulk of the tanker cars used to move oil by rail are unsafe. Now there are questions about risks posed by the type of oil being moved in them.

A good place to start to understand these risks is an otherwise obscure conflict between two oil companies in North Dakota. In May of this year, the pipeline company Enbridge discovered extremely high levels of hydrogen sulfide in its holding tanks in North Dakota and gave 24 hours notice to the shipper providing the high-sulphur oil that it would no longer take it.

A comparison of the Material Safety Data Sheets (MSDS) filed by the oil company Cenovus for Bakken crude and conventional oil show that Bakken shale oil crude has high levels of hydrogen sulfide and up to 10 times the benzene level of conventional oil.

Benzene is a toxic,cancer-causing and highly flammable substance present in all crude oil, but can be present at much higher levels in shale oil from the Bakken. There have been reports that high benzene levels from the oil spilled in Lac Megantic pose a threat to emergency personnel on the scene.

The reason that Enbridge closed its system to some Bakken crude, however, was the very high levels of hydrogen sulfide. Hydrogen sulfide is extremely deadly and highly explosive. One of the concerns noted in the MSDS sheet is its capacity to reach high levels within tanks that contain it:

“Hydrogen sulfide may accumulate in headspaces of tanks and other equipment, even when concentrations in the liquid product are low. Factors increasing this hazard potential include heating, agitation and contact of the liquid with acid or acid salts.”

Indeed, this was the problem identified by Enbridge. According to the statement of facts prepared by the U.S. Federal Energy Regulatory Commission:

“Enbridge points out that hydrogen sulfide is quite dangerous and has been recognized as such by the U.S. Government’s Occupational Safety and Health Administration (OSHA). Enbridge states that its test at the Berthold facility revealed levels of hydrogen sulfide vapor in one storage tank at 1200 ppm. Enbridge further states that occupational exposure to hydrogen sulfide at 50 ppm or more can cause shock, convulsions, or death. Enbridge also notes that low concentrations (trace to 10 ppm) can cause eye, nose, throat and respiratory system problems. Moreover, Enbridge points out that prolonged exposure can cause bronchitis, pneumonia, migraine headaches, pulmonary edema, and loss of motor coordination.  Additionally, Enbridge states that should hydrogen sulfide continue to be present in such high levels an affiliated downstream rail facility will shut down its facility to receipts from Enbridge.” (emphasis added).

The Federal Energy Regulatory Commission ruled in Enbridge’s favour. It acknowledged that placing limits on hydrogen sulfide levels and providing only one-day's notice to do so may cause "some difficulties for shippers", but that in this situation, "the Commission must place health and safety concerns above commercial matters."

This does, however, leave one to wonder where the crude that was no longer allowed to be moved by pipeline went, i.e. was it being shipped by rail in tanker cars that rupture easily upon derailment?

The rapid expansion of unconventional oil extraction (tar sands in Canada and shale oil in the United States) is not only a major threat to the climate, but also creates new safety issues that can’t be left to individual companies.

The Harper government, however, has been so 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. It has gutted environmental laws, and allowed the rapid growth of oil by rail to occur without assessing if the existing regulatory regime covers the new risks this creates.

That is why Greenpeace, along with over 50 other organizations from across the country, is calling for a comprehensive safety review of how we move oil in this country.

You can support this call by signing a petition here.