Two executives of a Fridley metal finishing company have been indicted in federal court for allegedly dumping wastewater contaminated with cyanide and other metals into the metro sewer system between 2002 and 2005.

Keith David Rosenblum, president and chief executive officer of Eco Finishing Co., and Martin Wayne Meister, the firm's plant manager, were charged in Minneapolis with violating the federal Clean Water Act, including illegal discharges, violating permit conditions and tampering with equipment. The indictment was unsealed on Wednesday.

Last year, a former chemist at the plant, Ted Matthew Gibbons, pleaded guilty to three violations of the act and was sentenced 18 months in prison.

Company attorney Peter Wold said that the two executives are not guilty and have "acted in good faith all along," adding that Eco Finishing is in compliance with law. "The company has continued to guarantee the quality of the process out there."

According to the indictment, Eco Finishing violated its discharge limits for three metals, including on one occasion releasing about 33 times more cyanide than allowed; did not submit regular required reports of its discharges, and tampered with monitoring equipment to falsify readings.

The firm uses chemical baths and rinses to electroplate, polish, color or coat metal products. It is required to remove much of the zinc, cyanide, nickel, lead, cadmium, chromium and other metals before discharging tens of thousands of gallons of industrial wastewater daily into the region's sewer system.

Metropolitan Council Environmental Services, which collects and treats wastewater in the region, declined to comment on how the contaminated wastewater affected its equipment or operations, or whether it may have entered the Mississippi River. Spokesman Tim O'Donnell referred all questions to the U.S. attorney's office, which did not return phone calls Friday.

Ray Bissonnette, a specialist in hazardous waste compliance and enforcement at the Minnesota Pollution Control Agency, said that in general the release of some wastewater contaminated with metals would not cause acute health or environmental problems once in the river, where they would be diluted.

A bigger concern, he said, is that the acidity of the wastewater might erode the concrete sewer pipes to the point that they would fail and leak, contaminating surrounding underground areas.

Staff writer M. L. Smith contributed to this report. Tom Meersman • 612-673-7388

Tom Meersman • meersman@startribune.com