The Husky Energy oil spill in Newfoundland is a wake-up call for British Columbians as the National Energy Board conducts yet another review of the Trans Mountain expansion project.

The east coast spill brings into sharp focus significant questions regarding the limitations of oil spill cleanup and recovery. It’s also a reminder of the very real possibility that an oil spill in a marine environment off the coast would be treated with Corexit, a chemical dispersant that would make a real-time experiment of us all — humans and non-humans alike.

In June 2016 the federal government quietly approved the use of Corexit 9500, a substance which Trans Mountain indicated in their submission to the National Energy Board they would consider using in the event of a marine oil spill off the B.C. coast.

The intended purpose of dispersants like Corexit 9500 is to break up oil slicks on the water’s surface by increasing the rate at which oil droplets form and move into the water column.

Chemical dispersion does not reduce the amount of oil entering the marine environment; rather, it aims to change where the oil goes and how quickly it gets there.

The idea is to turn the oil into small droplets which are more easily degraded by naturally occurring microbes, but it turns out that this plan may backfire.

In research conducted following the Deepwater Horizon disaster in the Gulf of Mexico, Corexit was found not only to be toxic to naturally occurring microbes that can degrade oil, but to actually suppress their oil-degrading ability.

Efficacy of Corexit on diluted bitumen unproven

There are significant concerns about the use of Corexit on a spill of diluted bitumen (dilbit), a blend of bitumen and chemicals, which would be carried by the expanded Trans Mountain pipeline.

Corexit’s effectiveness in dispersing dilbit is unproven at best, and a growing body of research indicates that Corexit is toxic to fish, wildlife, and humans.

Past experience on the B.C. coast has taught us that the rough conditions commonly encountered can render traditional oil spill cleanup methods — booms and skimmers — not just ineffective, but unusable.

Further, in their application to the National Energy Board, Trans Mountain noted that diluted bitumen can submerge in the water column and sink, thereby “reducing the effectiveness of a conventional spill response.”

In general, chemical dispersion is much less effective on weathered oils than on fresh oils.

Because the lighter components of dilbit weather so rapidly (through processes such as evaporation), the window during which chemical dispersion may be effective is significantly smaller than it would be for conventional crude oils.

Both Trans Mountain and Environment Canada examined the efficacy of dispersants on dilbit.

Environment Canada found that in breaking wave conditions, dispersants were able to disperse less than half of the dilbit released into the water. In non-breaking waves, dilbit was not affected at all by dispersant application. The report concluded that the physical properties of dilbit “limit the effectiveness of currently-available spill treating agents.”

Trans Mountain found that Corexit 9500 was ‘marginally effective’ on 6-hour weathered dilbit and ‘not particularly effective’ on more weathered dilbit. This very short time frame during which Corexit may be ‘marginally effective’ could pose major challenges given that in some locations, a full spill response could take up to 36 hours to arrive.

The risk would be magnified in the event that weather conditions prevented the use of booms and skimmers and dispersant was the only feasible option.

Corexit and wildlife

As noted, Corexit can also be toxic to wildlife.

For some species, such as herring embryos, toxicity occurs because Corexit does what it was designed to do: increase the concentration of petroleum hydrocarbons in the water column.

However, there is also a growing body of research, much of it conducted in response to the Deepwater Horizon disaster in 2010, which suggests that there is something else going on.

During this catastrophic spill, BP applied almost 7 million litres of Corexit, essentially turning the Gulf of Mexico and its human and wildlife inhabitants into an experiment on the short- and long-term effects of dispersant mixed with oil.

Blue crabs exposed to Corexit as part of a laboratory study to better understand the toxicity of chemical dispersants conducted by Louisiana Sea Grant. Photo: Louisiana Sea Grant via Flickr

Even at that time, there were concerns about the toxicity of Corexit: U.S. EPA administrators instructed BP to switch to a less toxic dispersant, but the company indicated that the alternatives were unsuitable and continued to use Corexit.

Now, research is showing that not only is Corexit itself toxic, but that a combination of Corexit and oil can be far more toxic than either product alone.

In fact, in marine plankton, Corexit and oil together caused toxicity up to 52-fold higher than oil.

This increased toxicity is due in part to the fact that dispersants can increase the exposure of fish and wildlife to the toxic parts of oil, to the extent that toxicity to rainbow trout embryos increased up to 300 fold.

U.S. Air Force pilots fly low over the Gulf of Mexico, releasing chemical dispersants as part of the BP Deepwater Horizon oil spill cleanup efforts on May 6, 2010. Photo: Technical Sergeant Adrian Cadiz / U.S. Air Force

However, some of the toxicity of Corexit 9500 also appears to be due to the surfactants it contains. One of these, known as DOSS, was found to be more toxic to the cells of rainbow trout than Corexit as a whole, while others (e.g. Tween 80 and 85) were also toxic, interfering with the ability of cells to metabolize petroleum hydrocarbons.

The combination of spilled dilbit and dispersants has the potential to negatively impact B.C.’s marine mammals, including endangered killer whales.

Trans Mountain vs. killer whales: the tradeoff Canadians need to be talking about

Following the Deepwater Horizon disaster, 101 cetacean carcasses that washed up on the northern shores of the Gulf of Mexico were associated with spilled oil, although estimates of the actual number of mortalities ranged up to 50 times higher.

For cetaceans, which must surface to breathe, the inhalation of evaporating toxic components of dilbit combined with airborne Corexit 9500 poses a serious risk.

Human danger

Humans are at risk too.

Workers attempting to clean up the Deepwater Horizon spill experienced coughing, wheezing, eye, skin, and lung irritation, nausea, vomiting, and rashes, with some continuing to experience symptoms over a year later.

In Coast Guard personnel who assisted with clean up, dispersant exposure was linked to acute respiratory symptoms. In addition to its own toxicity, Corexit can also increase exposure to the toxic components of oil by creating oil particles so fine that they can become airborne and enter the lungs.

Crewmembers from the vessel Braxton Perry recover a deflection boom after three days of controlled burns in the Gulf of Mexico. Photo: Mass Communication Specialist 2nd Class Justin Stumberg / U.S. Navy

This airborne mixture of oil and dispersant can travel up to 80 kilometres.

In Sweden and the U.K., Corexit has been banned due to the risk it poses to workers.

What stands out from this growing body of research is how poorly we understand the toxicity of dispersant combined with any type of oil.

There are a vast number of potential toxicity scenarios, depending on the chemicals present, exposure routes, weather conditions, and species, among many other variables.

Almost three decades ago, researchers warned about these complexities, stating that “rigorous toxicological comparison of untreated and dispersant-treated oil is complicated by the fact that when oil, sea water, and dispersants are mixed, a complex multiphase system results. In this complex system, aquatic organisms can be exposed to many toxicants, in many forms, which can have several modes of action.”

Why is Corexit on the table?

Why, then, would the federal government even attempt to pursue the Corexit route?

The answer may be largely a question of optics.

Undispersed oil can eventually reach shorelines, coating birds and mammals while creating a public relations nightmare for the government of Canada, the new owner and operator of the Trans Mountain pipeline and oil tanker project.

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Canada's northwest coast stands alone as one of our planet's last unspoiled coastlines. Its rich assemblage of wildlife, wild rivers and intricate landscapes makes it qualitatively different from any other place in the world.

British Columbians have increasingly come to cherish this maritime commons of waters, islands, and forests. According to an Angus Reid public opinion poll, wild salmon — the foundation species on which this coastal bounty is built — are as important to British Columbians as the French language is to Quebec.

With March 24 marking the 25th anniversary of the Exxon Valdez oil spill, this disaster provides a lens into considering the Enbridge Northern Gateway oil tanker and pipeline project and the risk it poses to wild salmon, one of our country's greatest natural assets. The Valdez spilled more than 41 million litres of crude oil. Negative impacts from the spill are still felt, with only 13 of the 32 monitored wildlife populations, habitats and resource services injured in the spill listed as fully “recovered” or “very likely recovered.”

A recent report by the Raincoast Conservation Foundation concluded that the consequences just to wild Pacific salmon from Enbridge's project are not a risk worth taking. The report, "Embroiled: Salmon, Tankers and the Enbridge Northern Gateway Proposal," explores the connections between the oil industry's anticipated activities on the B.C. coast and how those activities could adversely affect salmon.

The Queen Charlotte Basin, the backdrop for Enbridge's oil tanker routes, is home to more than 5,000 spawning populations of wild salmon. These fish represent 58 per cent of Canada's Pacific salmon and are the foundation of B.C.'s remarkable coastal ecology, the iconic wildlife that rely on them and the basis for multi-million dollar economies in eco-tourism, salmon-based tourism and the salmon resource sector.

Salmon naturally have poor odds for survival. On average, only one salmon for every thousand eggs that a female lays will return to spawn. These odds have further declined in recent years due to intense human activities in salmon watersheds and in the ocean. Oil tankers and terminals present a new, added threat to salmon survival.

With a fresh oil spill, toxic vapours from the oil threaten living organisms that breathe in air and water. In contrast, other components in oil, known as polycyclic aromatic hydrocarbons (PAHs) are of equal, if not greater, concern. These compounds can persist in the environment for years, if not decades, and can continue to harm organisms long after the oil first spills. Even low levels of exposure to PAHs — in parts per billion — can have lethal consequences for salmon.

The most vulnerable period for salmon to be exposed to oil is during their egg incubation in the spawning gravels. Embryos and larvae are 10 times more sensitive to oil than adult salmon because their high lipid content attracts oil. In the gravels, chum and pink salmon are at the highest risk to marine oil spills because their parents tend to spawn in the lower reaches of streams, where oil residue can reach the gravels.

Early life is the next most vulnerable period from an oil spill. When young salmon first migrate to sea, they rely on estuaries and near-shore waters for food, protection, and safe migration. These areas are usually the most heavily impacted by oil spills.

Importantly, there are threats from industrial oil activities even in the absence of large spills. Oil tankers and terminal activities bring routine small spills, dramatically altered shorelines, river water extraction, increased underwater noise, ship wakes, turbidity and impacts to salmon food sources.

In Alaska's Port of Valdez in Prince William Sound, the rise and accumulation of PAHs in ocean sediments from small, chronic oil spills (while loading tankers), tracks perfectly the volume of oil shipped. In B.C., stressors from oil industry habitat loss and toxicity would add to cumulative affects that push salmon — most of which are already at their lowest levels of known abundance — beyond their ability to survive.

Enbridge has maintained there are no significant risks or consequences to salmon from their proposed Northern Gateway project. This is based on their wholly inadequate assessment of baseline conditions and project impacts, and is exacerbated by their failure to adequately consider cumulative impacts, including climate change. Consequently, the conclusions arrived by Enbridge cannot be scientifically supported in many cases.

In the absence of an adequate assessment of risk by Enbridge (risk defined as the probability of an oil spill times the consequence of an oil spill), Raincoast performed a limited risk assessment to demonstrate the type of analysis that should have been undertaken. Our assessment found that more than 400 spawning populations of salmon lie adjacent to the confined channels of the tanker routes and that these streams contain some the highest densities of spawning salmon on the B.C. coast. These salmon streams drain into Enbridge's highest risk routes for tanker accidents.

Salmon, and the wildlife and human communities that they support, are the very soul of British Columbia and the lifeblood of our coastal ecosystem. Despite the National Energy Board's blessing that Northern Gateway should go ahead, British Columbians are clearly not willing to surrender these values and way of life to the oil industry.

This article was co-authored by Misty MacDuffee, a biologist and fisheries ecologist with Raincoast Conservation Foundation.

Image via NOAA

The Narwhal’s reporters are telling environment stories you won’t read about anywhere else. Stay in the loop by signing up for our free weekly dose of independent journalism.