WASHINGTON - BP Plc is making oil leaking into the Gulf of
Mexico more toxic to marine life by mixing it with Nalco Holding Co.'s
dispersants, an environmental group said.
Oil and Nalco's Corexit dispersants combined have higher
toxicity than either substance alone, Richard Denison, a senior
scientist at the Environmental Defense Fund, said today by telephone.
Denison yesterday posted on his website an analysis based on technical
product bulletins that Nalco provided to the U.S. Environmental
"Dispersed oil is more toxic than undispersed oil,"
Denison wrote in his posting. "The dispersant maker's own test data
demonstrate that the combination of oil plus dispersant is quite a bit
more toxic than the dispersant alone and -- even more significant -- the
combination is more acutely toxic than the oil by itself."
More than 1.2 billion gallons of dispersants have been
sprayed into the Gulf, according to the Deepwater Horizon Unified
Command linking companies and government agencies responding to the
spill. BP has applied Corexit from planes and from the seafloor to help
keep the worst oil spill in U.S. history from damaging wetland habitats.
According to Denison, 2.61 parts per million of a
mixture containing 1 part Corexit EC9500A and 10 parts oil killed half
the silverside fish in a 96-hour study cited in a Nalco bulletin. Oil
alone requires a higher concentration -- 10.72 parts per million -- to
achieve the same toxicity, and Corexit requires 25.2 ppm, Denison said,
citing the bulletin.
Corexit reduces total environmental damage, said Charlie
Pajor, a spokesman for Naperville-based Nalco who didn't dispute
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"It's more toxic to marine life, but less toxic to life
along the shore and animals at the surface because the oil is not at the
surface," Pajor said. "It's generally less environmentally harmful than
allowing the oil to migrate to the surface."
Nalco rose 44 cents, or 2 percent, to $22.50 at 12:41
p.m. in New York Stock Exchange composite trading. The shares declined
14 percent this year through yesterday.
Based on the total used so far, the dispersant-oil
mixture is capable of killing half the fish across 4 square miles down
to the ocean floor, Denison said. If diluted 10-fold, the oil-dispersant
mix would kill 5 percent of fish across 40 square miles, he said.
Nalco's dispersants are approved by the U.S.
Environmental Protection Agency, said Tristan Vanhegan, a BP spokesman.
He declined to comment specifically on the Environmental Defense report
because he said he hadn't seen it.
"We continue to use Corexit while looking for
alternative products," Vanhegan said. "The EPA has asked us to look for
less toxic products."
Nalco Chief Executive Officer J. Erik Fyrwald met with
members of Congress on May 26 to assure them that Corexit is safe after
the EPA demanded BP limit its use.