So it seems from what I’ve been reading that the dispersant Corexit 9500 is a toxic and hazardous chemical that we shouldn’t go anywhere near in cleaning up the mess caused by an oil spill.
New Zealand is currently facing its worst maritime environmental disaster in history. The Rena cargo ship grounded on a reef in the Bay of Plenty, 12 nautical miles from landfall, over a week ago, in clear conditions. The captain has this morning been charged, with further charges under the Environmental Management Act still likely, and some of the containers from the laden ship have fallen off overnight.
My concern, which is echoed by many New Zealanders, is why during the four clear days that followed the grounding, nothing was done to minimise the damage and prevent the oil from reaching landfall????
But back to the ambulance at the bottom of the cliff.
What is Corexit?
An oil dispersant is basically a detergent, like your diswashing detergent. It disperses or breaks up the oil film into small droplets that intermix with seawater. Corexit is a line of oil dispersants or solvents, originally developed by Exxon and now manufactured by Nalco Holding Company (NHC) of Naperville, IL. Interestingly, NHC is associated with Exxon and British Petroleum (BP). Corexit is not a very efficient oil dispersant; there are others that are better.
Corexit EC9500 (the one we are apparently going to be using to clean up Rena’s mess) is mainly comprised of hydro-treated light petroleum distillates, propylene glycol and a proprietary organic sulfonic acid salt. Propylene glycol is a chemical commonly used as a solvent or moisturizer in pharmaceuticals and cosmetics. An organic sulfonic acid salt is a synthetic chemical detergent, such as that used in laundry detergents, which act as a surfactant to emulsify oil and allow its dispersion into water. The chemical works by massively speeding up the biological break down of the oil, breaking it into smaller parts and dropping it beneath the water’s surface.
Is Corexit Safe to Use?
The short answer is “No!” Corexit is highly toxic to humans as well as marine life.
According to the Material Safety Data Sheet (MSDS), Corexit 9500‘s “potential human hazard is: High.” It can cause central nervous system depression; nausea; unconsciousness; liver, kidney damage; and red blood cell haemolysis with repeated or prolonged exposure through inhalation or ingestion.
It is popular with regional councils here in New Zealand , but in Wellington its considered a last resort. The chemical has been banned in Sweden, while in England it’s heavily restricted and not allowed anywhere close to shore.
The Green Party of New Zealand have asked the government to look at other options, rather than just jumping in, but the environmental minister insists that Corexit is no more toxic than dishwashing liquid. He really needs to do more research!
In My Opinion
There are experts who think that oil dispersants of whatever variety shouldn’t even be used.
Dispersing the oil neither eliminates it nor decreases its toxicity. All dispersants do is to break the oil into small particles, where it becomes less visible. But the oil’s still there, spewing toxicity at an even greater rate (due to higher surface area), except now it’s pretty much impossible to skim or trap or vacuum or even soak up the oil particles at the shoreline because most of it will never make it to the shoreline. Instead, the toxic crude oil AND the dispersant will be spread all over the ocean’s waters.
In effect, to “disperse” the oil means it will NEVER be cleaned up. It will just stay out there, polluting and poisoning the ocean and marine life, including the fish, shrimp, mollusc that we humans consume as food.
And if using oil dispersants is unwise, it is approaching madness to use a dispersant as toxic as Corexit.