Environmentalists are urging Canada's Conservative government not to loosen rules involving a substance used for treating oil spills in water, citing research questioning its ecological impact.

 

The oil dispersant, Corexit EC9500A, was deployed during the deadly Gulf of Mexico Deepwater Horizon disaster in 2010. The U.S. Environmental Protection Agency had concluded in a June 2010 report that Corexit 9500A was "slightly toxic" to mysid shrimp found in the Gulf of Mexico.

 

A scientific study said in March that Corexit EC9500A was toxic to corals near the BP spill site.

 

Canadian Environment Minister Leona Aglukkaq proposed in July that energy companies should be allowed to use the product and another spill-treating agent supplied by Nalco, a unit of U.S. environmental and industrial services company Ecolab Inc.

 

Companies in both countries can already use these dispersants on a restricted basis with permission, but Aglukkaq's proposal would loosen those rules in Canada.

 

Aglukkaq's department said the substances were not harmful in its tests on a range of species, but it has not yet announced a final decision.

 

Nalco's website says dispersants are safe and effective, often containing ingredients similar to household cleaning products and cosmetics.

 

But Temple University biology professor Erik Cordes, who supervised the latest study's lead author, Danielle DeLeo, said the effect on corals could be significant since they provide habitat for other organisms.

 

Aglukkaq's department, the EPA and a spokesman for Minnesota-based Ecolab declined to comment on the study.

 

The EPA said it was reviewing its own rules about treating spills, based on "lessons learned" from the BP incident, while encouraging development of safer and more effective products.

 

Former Toronto mayor David Miller, who is president of conservation group WWF-Canada, urged Aglukkaq not approve Corexit 9500A, which he said did not have a reliable enough track record. Writing in a blog, he also said the proposed approval gave a "false impression of a quick fix for oil spills."

 

Environmentalists and opposition parties have criticized the right-leaning Conservatives in recent years, accusing them of weakening regulation of the energy sector.

 

The Conservatives, now in the middle of a hotly contested Canadian election campaign, say they are promoting responsible development of the energy industry and that the recent proposal to approve new dispersants would strengthen environmental protection through a "world-class" regulatory system.