Everyone agrees that the Deepwater Horizon oil spill is a disaster for the Gulf of Mexico. But now fishing industry groups and Louisiana officials are wondering if chemical dispersants being used to limit the spill may lead to a more long-lasting disaster.
"It's very scary," said John Williams, executive director of the Tarpon Springs-based Southern Shrimper Alliance, which has written to federal officials to challenge the use of chemical dispersants on the oil. "They say it's the lesser of two evils, but how do we know it's the lesser evil?"
Fishermen say they are afraid the dispersants could create a series of widespread dead zones in the gulf, contaminating or killing marine life.
"Our entire seafood industry in the gulf is at risk here," said Williams, whose group represents shrimpers from North Carolina to Texas.
No one but the Texas-based manufacturer, Nalco Energy Services, knows exactly what's in Corexit 9500, the dispersant BP has been spraying on the slick. The company says it may pose a risk for eye and skin irritations and can cause respiratory problems, but "no toxicity studies have been conducted on this product."
So far, airplanes have sprayed 315,000 gallons across the gulf's surface to control the spill.
On Monday, three Louisiana officials wrote to Tony Hayward, BP's chief executive, expressing "serious concerns about the lack of information related to the use of dispersants." They said they wanted "a BP commitment that the dispersants being used to fight the oil spill will not cause irreparable short term or long term harm to our wetlands, coast, environment, marine life, wildlife or people."
Corexit 9500 has been approved for use by the U.S. Environmental Protection Agency, although tests indicate it can be stored in the tissue of organisms. More than half of the agent in tests wound up storing in sediment, with less absorbing into the water.
Every time EPA Administrator Lisa Jackson has met with fishing groups about the spill, she has faced questions about what effect the chemicals in the dispersants might have on seafood, agency spokeswoman Andora Andy said. For now, she said, the agency is awaiting test results.
"A dispersant doesn't get rid of oil," said George Henderson, a senior scientist with the Florida Fish and Wildlife Research Institute in St. Petersburg who is the state's top science adviser on the oil spill. "It just transforms its movement."
As the name implies, the chemicals break up the slick "into very finely dispersed oil droplets," according to a statement on BP's website. At that point, the oil could evaporate or be consumed by oil-eating bacteria.
It could also be eaten by fish, poisoning them. Or it could wind up coating their scales, harming their ability to swim.
Five years ago, a 400-page National Academy of Sciences study concluded that the decision to use a dispersant requires making a choice: saving the beach at the expense of the ocean.
"It's all about trade-offs," said Beth McGee, senior water quality scientist with the Chesapeake Bay Foundation and one of the authors of the 2005 study. "You look at the resources at risk and you make a choice." While there may be some sickness and fatalities among the fish population, she said, "you hope you're saving some beaches or marshes."
However, she added, anywhere the oil ends up, "it's going to take a while for the system to recover."
"You're making a decision to save your birds at the expense of your larval fish and shellfish population," agreed Henderson. But marine life should be able to bounce back more rapidly, he said.
That's when the dispersants are sprayed on the surface, as their manufacturer recommends. Over the past week, BP has been testing a radical approach, shooting the dispersants at the source of the leaks a mile beneath the surface, even though EPA officials say the effects of underwater use "are still widely unknown."
The most recent subsea test occurred Monday, according to BP's Bryan Ferguson, and it was "viewed as very satisfactory with regard to the results." However, Ferguson could not say how many gallons of dispersant BP has sprayed underwater.
One 2006 study found that oil droplets treated with a chemical dispersant didn't degrade nearly as fast when they were in very cold water — and the water a mile deep is just above freezing.
The shrimpers are worried that using dispersants at such a depth would guarantee that it would spread the oil droplets and dispersant on the sea floor, where shrimp larvae and other organisms could be affected.
There are no federal standards for how much dispersant could be present in seafood consumed by humans, said Nancy Thompson, director of the Northeast Fisheries Science Center under the National Oceanic and Atmospheric Administration. Thompson has been dispatched to Mississippi to lead a NOAA team testing the effects of the spill and cleanup activities on fish.
"It's kind of disturbing," said Robert McKee, a Fort Lauderdale lawyer who's part of a consortium of attorneys representing the United Commercial Fishermen's Association and the Louisiana Environmental Action Network. "There's no way of knowing how many generations of sea life and how many generations of human life are going to be affected."
Times researcher Caryn Baird contributed to this report, which contains information from the Associated Press and the Los Angeles Times. Craig Pittman can be reached at (727) 893-8530 or firstname.lastname@example.org.