Thank you.
Essentially, the precautionary principle just needs to move beyond the traditional list of substances, simply for one reason, talking about those PAHs.
We've often modelled the bioaccumulation of these compounds based on the 16 U.S. EPA priority substances already on the list. They are not bioaccumulative, and they're readily metabolized. However, we're finding that those alkylated forms of those PAHs do bioaccumulate. If you proceed based on an old list, we see they don't bioaccumulate, so it's not an issue, but if we just expand the list and look beyond those pure parent compounds, we'd see that in fact they do bioaccumulate.