WAYNE - Authorities say a new playground and dog park in Wayne may have been built on contaminated soil.

The site was once the home of a plant for the W.R. Grace Company. Between 1948 and 1957, the site was used to mine thorium, a radioactive element. Radioactive waste and contaminated building rubble were stored in pits on the site for decades.

The plant was shut down more than 40 years ago. After a major cleanup effort where mounds of radioactive dirt were hauled away, officials say the site is now safe.

Terry Zack, of Pompton Lakes, questions the decision to build a park at the site. "Why would they ever build a park where you're going to bring kids and animals when it was a contaminated site? I don't think I would trust it," he says.

Officials say cleanup was completed in 2003 and that the site was taken off the EPA's superfund registry just last year.

In a final report in 2008, the EPA said the cleanup on the Wayne property was successful and no further action was needed.