Why BP doesn't have to tell the EPA—or the public—what's in its dispersants.
Why, you might ask, was BP able to pump the Gulf full of chemicals that have never been tested for their human and environmental safety? The answer lies, in part, in the Toxic Substances Control Act, the 34-year-old law that governs the use of tens of thousands of hazardous chemicals. Under the act, companies don't have to prove that substances they release into the air or water are safe—or in most cases even reveal what's in their products.
In the case of dispersants, companies must ask the EPA for permission to use specific products—but the only basis for approval is whether those products are effective at breaking up oil. Companies are required to test the short-term toxicity of the dispersant and the oil-dispersant mixture on shrimp and fish, but those results have no bearing on approval, and there's no requirement to assess the long-term impact. In fact, it's the EPA that must prove an "unreasonable risk" if it wants companies to disclose what is in the dispersant—hard to do when the agency, you know, doesn't know what's in it.