EPA has released results of its first round of chemical testing of dispersants used in the Gulf. The report downplays toxicity, but as scientist/blogger Richard Denison points out – the report offers little new information and still leaves unresolved the bigger questions, such as what toxicity occurs when dispersants and oil combine, and what happens when that highly dispersed oil/dispersant brew is spread across vast areas and throughout the water column.

A month after promising to test the toxicity of dispersants used against the Gulf oil spill, the EPA has yet to complete those tests – meanwhile more than 1.4 million gallons have been dumped in the Gulf with unmeasured consequences, reports Mother Jones. EPA’s position is that the dispersants are less toxic than the oil, but that raises the question: are we just adding to the total toxicity of the spill?

Update: Check out the latest information on the toxic potential of ingredients in oil dispersants>

The government wouldn’t dare let a doctor give out an experimental drug without years of extensive testing, yet it has allowed British Petroleum to flood the Gulf of Mexico with more than a million gallons of a secret chemical compound in an untested experiment on human communities, hundreds of animal species, and myriad ecological systems.

We’re talking about Corexit and other dispersants, made up of classified chemicals and spread over and injected into Gulf waters to break up BP’s oil spill. The spill alone is in many ways unmatched in human history, scientists say, and because of dispersants may be wreaking special devastation in the Gulf. Aside from the fact that dispersants never before have been used on such a vast scale, we have been forced to guess at the danger they pose because BP and the dispersants’ manufacturer refused to reveal the ingredients.

Today, after Earthjustice demanded the information through a Freedom of Information Act request, the Environmental Protection Agency finally provided a list of what’s in these chemical compounds. Now, we can turn to experts to assess their danger. Our clients, the Gulf Restoration Network and Florida Wildlife Federation, who have long worked to protect the Gulf, must know what is happening to its rich fisheries, sea turtles, birds, and entire ecosystem.

At one point, the EPA told BP to quit using Corexit because of its toxicity and to find a less harmful dispersant, but BP ignored the order and the EPA acquiesced. The agency, which is all that stands between us and the toxic effects of dispersants, said the urgency of the spill situation was worth the risk. But, who is to say what the risk is unless we know what is being deliberately put into the waters, how it interacts with oil, and what its inherent toxicity is? BP certainly can’t be trusted.

We already know what untreated oil does to us and the environment. It is a thick, suffocating mass that kills and maims mostly in upper water columns and as it comes ashore, is visually horrifying and creates economic havoc in the tourism and fishing industries. Dispersants are supposed to neutralize some of that harm, but what we are seeing with this Gulf spill is unlike anything we’ve seen before.

Even without dispersants, the oil likely would be found throughout the water column because it is flowing from a mile deep at hundreds of miles per hour. But, dispersants have been injected directly into that oil as it escapes and have been spread by boat and plane across hundreds of square miles of surface. BP tried to convince us that most of that oil disappeared, but scientists have found clouds of oil particles and droplets miles wide and long, hovering at various depths from the sea floor where many creatures dwell to surface waters where most fish and other animals feed and spawn.

One plume is 15 miles wide, 3 miles long and about 600 feet thick. Scientist Samantha Joye of the University of Georgia, who led an expedition tracking the oil plumes, says: “The primary producers—the base of the food web in the ocean—is going to be altered. There’s no doubt about that. We have no idea what dispersants are going to do to microorganisms. We know they are toxic to many larvae.” Of special concern is the larvae of the endangered western bluefin tuna, which spawns exclusively in these Gulf waters. Of no less concern is the harm we all have seen to oiled birds, turtles, dolphin, and fish.

And then there are the long-range potential impacts on human health. Dispersants don’t eliminate oil, they make it less visually obvious by breaking it into small pieces spread over a vast area and throughout the depths. This makes the oil/dispersant droplets available to all the life forms that may ingest it and in turn are ingested. Anything in the oil or attached to it are thus entering the food chain. We know about oil’s toxic components – human carcinogens like napthalenes, benzene, toluene and xylenes—but we don’t know about the dispersants that are partnering with it.

Nalco, the manufacturer of Corexit, put out a release trying to allay concerns about the ingredients in its dispersants, but its statement raises more concerns than it answers. First, it asserts that all of the ingredients “have been determined safe and effective by the EPA.” While the Food and Drug Administration makes such determinations for drugs, the Toxics Substances Control Act is so weak that it does not require that EPA make such safety findings before chemicals are allowed on the market. That is why a diverse health, environmental, and labor coalition (including Earthjustice) are calling for an overhaul of that law.

Second, Nalco tries to prove that the dispersant’s ingredients are safe by pointing to their presence in cosmetics, lotions and stain blockers. That offers little comfort. Cosmetics and lotions often contain phthalates, which have been associated with reproductive impacts and endocrine disruption. And some stain blockers contain ingredients classified as cancer-causing or neurotoxins.

When we have more information about how the dispersant ingredients work, we will let you know.