A Shelburne County environmentalist is raising concerns about a toxic chemical that could be used off Nova Scotia in the future.

When the Deepwater Horizon oil platform erupted in flames in 2010, it spewed oil into the Gulf of Mexico, but some research says the cleanup was worse because about 6.8 million litres of the chemical Corexit 9500A was used to disperse the oil.

The dispersant used by oil company BP, when mixed with crude oil, was found to be 52 times more toxic than oil alone to some microscopic plankton-like organisms called rotifers.

"When you mix this stuff with the oil, you create a compound that is substantially more dangerous than even the dangerous dispersant on its own or even the dangerous oil on its own and this is the issue that we have," says John Davis, a founder of the No Rigs Coalition.

He says Shell has already put out bids to use Corexit if there is a spill at a well planned for the Shelburne Gully.

"The creators of CoRexit will tell you it's less toxic than dish soap. All you have to do is read the warning label to know that it’s a highly, highly dangerous chemical.… There is no doubt in my mind that if Shell made the effort they could find ways to clean up the oil and not just be prepared to disperse it and put it under water and out of sight," he says.

'Total abdication of regulatory responsibility'

Davis says there is legislation in place to prevent the use of chemicals like Corexit, “but what happened here is that the federal government has decided to put forward legislation called Bill C-22 — which in fact creates a circumstance where the oil company can go and utilize the product, the dispersants, and then report after the fact to the regulatory agencies. It is an absolute, total abdication of regulatory responsibility.”

Bill C-22 was introduced by the federal minister of Natural Resources earlier this year.

It would pre-approve emergency plans for oil and gas companies to deal with spills, such as the speedy use of dispersants, or chemicals used to break oil into smaller particles in the event of an oil spill at sea.

Davis says he worries the chemical could end up on the Georges Bank, pointing out the Labrador Current would carry any material right to the fertile fishing grounds.  

"It’s that [upwelling of water] that provides much of the nutrients that makes Georges Bank such an important biological place — and so important to us as an economical generator," he says.

A publication in the February 2013 issue of the scientific journal Environmental Pollution, found that on their own, the oil and dispersant were equally toxic. But when combined, the oil and dispersant increased toxicity to one of the rotifer species by a factor of 52.

'High and immediate human health hazards​'

Dispersants cause giant pools of spilled oil floating atop the sea to break up into tiny droplets that then dilute with water just below the surface. The process helps creatures including turtles, birds and mammals that need access to the surface, and also ensures less oil flows ashore where it can choke coastal wildlife. However, it increases the amount of oil just below the surface, potentially contaminating the organisms that live there.

Scientists at the Autonomous University of Aguascalientes in Mexico and the Georgia Institute of Technology now say Corexit 9500A is far more harmful than previously thought to a key dweller of those sub-surface depths.

An Environment Canada study states the dispersant is 27 times safer than common dish soap, but some say that figure is dangerously misleading. The study also states that five of Corexit's 57 ingredients are linked to cancer and can pose "high and immediate human health hazards."

In all, the British Petroleum oil leak was the largest offshore petroleum spill in U.S. history, sending 4.9 million barrels (584 million litres) of crude into the Gulf of Mexico.