There's always a “but” in science. No matter what you look at, there always will be a “but”.
Science doesn't progress by giant leaps. It progresses by a series of very small steps. Of course, we're always trying to correct past errors. We hope that if we substitute a substance, it will be safer than the one before it. Obviously that's what the intent is, but it's not always easy to know that. You can't predict. And truly one of the main points I try to make is that one should never suggest that they have knowledge that actually doesn't exist. There's just way too much that we don't know about what the consequences are of regulating and substituting.
I'll give you an analogy, perhaps. Right now we're talking about PFOAs. It's been in the paper for the last couple of days because of the ban on certain perfluorinated compounds, especially the telomers that are used as stain removers. I think that this is a good thing. I think that we do have accumulating evidence of problems there, but there are going to be consequences. We use these products in order to resist stain. If that's not going to work, people will have more stains. They will go to the dry cleaner more often. Then we worry about the tricholoethylene that is used by dry cleaners. That's a very legitimate worry. Tricholoethylene is one of these persistent chemicals that I think we need to do something about.
Then we talk about replacing that maybe with liquid carbon dioxide. The manufacturing of liquid carbon dioxide is not a totally benign procedure either. There are other ways to make stain-resistant compounds. There are some very new technologies, including carbon nanotubes that you've probably heard about. This is all based on the buckyball technology, which is really quite fascinating, because it's essentially a discovery of a new form of carbon. Everyone knows about graphite and diamond as a form of carbon. Well, we have another form--these so-called buckyballs, after Buckminster Fuller, who was the architect who designed geodesic domes. These substances can be incorporated into fabrics in order to ward off stains.
We've already seen a demonstration in Chicago in which the demonstrators dropped their pants that they had purchased at Eddie Bauer, because Eddie Bauer was, according to them, using Teflon to keep off the stains. They weren't even using Teflon. What they were using was the buckyball technology, so they even got that part of it wrong. But in the next demonstration they had, they at least corrected that and they were demonstrating against the use of these nanoparticles in stain-resistant materials. Why? Because the suggestion is that we don't know what is going to happen if we expose the public to these nanotubes. The public, of course, has been sensitized to this because they read Michael Crichton's book, Prey, which suggests that these nanoparticles can somehow multiply or self-assemble and turn the world into toxic goo, as he calls it.
So there is always a “but”. Yes, we try to replace things with the new, and it doesn't always work better. We have to make some educated guesses on these things. We have to look at each class of chemicals very specifically. We have to look at the molecular structures. We have to look at the amounts. I think that there are thresholds, but obviously not everyone agrees with that.