The EPA says a new round of dioxin sampling at Route 66 State Park confirms it poses no risk to park workers and visitors.
But the former town of Times Beach is just one of many sites in Missouri that may need more testing.
EPA spokesperson Chris Whitley says there are almost 200 sites in Missouri - some industrial, some residential - that at some point have been tested for dioxin.
Forty-two had enough of the potentially cancer-causing chemical that they needed to be cleaned up. But Whitley says the EPA is now giving them a second look: "This is going to be a long-term effort in terms of evaluating, are there places that we would go back to, to either do additional sampling, and if sampling would bear anything out, whether there would be additional work done."
Whitley says another 155 sites have never undergone remediation, because previous testing found little or no dioxin. Those sites are not currently under review.