CARTERET - A proposed environmental cleanup of a toxic site along the Rahway River could have an unintended consequence, a Kane In Your Corner investigation finds. Some environmental groups say it could leave surrounding towns more vulnerable to flooding in the event of severe storms.

At issue is a plan to clean up the old American Cyanamid site in Carteret, which is contaminated with cyanide-tainted sludge. The proposal, nearing final approval from the New Jersey Department of Environmental Protection, calls for the site to be covered with up to 29 feet of soil and concrete. Some say creating a “mountain” that could cause rainwater, that would normally pool on the 85-acre site, to cascade into the adjacent Rahway River, worsening flooding in nearby communities.

The concern is acutely felt in Cranford, where the town hall, first aid station, and more than 350 homes were overrun by floodwaters during Hurricane Irene in 2011. Former Cranford Mayor Dan Aschenbach, who now chairs the Rahway River Stormwater Advisory Board, says his group has been working to reduce flooding risks by, among other things, convincing homeowners and businesses to build rain gardens, depressions in the earth that are often filled with decorative rocks or wildflowers that are intended to collect water that might otherwise run off.

“If the state allows this major development to go on and creates a flooding issue, all that effort has been wiped out,” Aschenbach says. He wrote a letter urging the NJDEP to consider the flooding impact before granting final approval to the plan.

Supporters of the plan argue the size of the site is so small compared with the size of the flood plain, that any impact on flooding will be minimal. “It’s pure speculation,” says Michael Sica, chief of staff to Carteret Mayor Daniel Reimen. “I have not seen one bit of data that indicates there's going to be a flooding problem caused by this particular project.”

The proposal is already controversial. Last month, a Kane in Your Corner investigation revealed the NJDEP issued preliminary permits for the project over the objections of many of its staff members, who believed the proposal to cover the site with tons of soil and cement could wind up squeezing the toxic sludge into the Rahway River. Kane In Your Corner also discovered the company that would do the work, Soil Safe Inc., has been cited for environmental violations in two previous New Jersey projects.