Scrap metal recycler Grimmel Industries is facing a fine of up to $532,500 from the U.S. Environmental Protection Agency for allowing polluted stormwater to flow into surrounding waters at its Portsmouth, N.H, facility.

The alleged violations of the Clean Water Act include discharges that contain metals, suspended solids and chemical oxygen demand that exceed permit benchmarks. Further, the stormwater discharges contain mercury and polychlorinated biphenyls (PCBs), the EPA said in a news release.

Grimmel also failed to perform required inspections or sampling and discharged stormwater and dust suppressant wastewater to the Piscataqua River, which is not allowed by the permit. The facility is next to the river.

Following an EPA order in April 2011, Grimmel stopped its unpermitted process water discharge and took measures to minimize pollutants in its stormwater, the agency said.