NRC (part of the NAS) released a report saying that EPA’s risk assessment is bogged down with all the details they don’t know and burdened with assumptions that aren’t helpful. Since they were piling on the agency, they threw in the fact that it was silly to look at chemicals in isolation as opposed to a mixture. Well, they were right. As to the issue of always wanting more information, I’ve wrote about that before, this, I think, is a huge issue for public health today (Science: the enemy of public health).
They are right about the other stuff too. If you’re interested, you can go read the report. However, spend some time to shed a tear for the EPA because while the recommendations make sense, some are completely impractical given the statues that give authority to the EPA. For one, how in the heck do you regulate a mixture. Let’s say that chemical A, B, and C all contribute to some disease through drinking water. They are all produced by different companies.
Problem 1: Who should have to pay for the research into the mixture? Dividing up this cost is likely to take a long time. Especially since EPA doesn’t have very good ways of forcing companies to do toxicology tests on single chemicals.
Problem 2: If each one alone isn’t enough to cause the problem, how do you decide how to regulate them. There isn’t a way that is obviously fair and therefore, every decision will be fought in court saying that the EPa can regulate it and once that winds it’s way through the courts, we’ll start another round saying the other company should be the one cleaning it’s act more.
Problem 3: How do you test mixtures that exist in different proportions in different communities? You can’t do tox tests on every combination that exists and a method that tries to determine what the combinations will do is near impossible (we don’t know how to do it for one chemical. How much luck do you think we’ll have with a handful?)
I could go on about other practical barriers that the EPA has in implementing these results. But suffice it to say, the EPA can’t apply these recommendations under the current laws. But that’s not enough; as the NAS notes, the carcinogen TCE has had risk assessment in progress since 1980 and it is projected to be done in 2010. One could rightly ask why bother doing risk assessments at all? It seems that we can either watch the toothless EPA become more and more irrelevant, or Congress can rethink the laws that govern the EPA. And it’s not as hard as you would think. Only a few miles away, the FDA does full reviews on drugs to be marketed with greater scrutiny in 9 months or less. There’s no reason why the government should make timely and sound decisions about chemicals we take intentionally, but not those that we are involuntarily exposed to.