Chemetco - Air-borne Dioxin Production

Air-borne Dioxin Production

A scientific study by the Centre for the Biology of Natural Systems (CBNS) Queens College of the City of New York, individually names Chemetco as one of the top ten individual contributors of dioxin deposition at eight Nunavut land receptors, from a total of 44,000 potential sources in the United States. As the report puts it:

"…the effort detailed in this report is a response to the evidence that Nunavut is especially vulnerable to the long-range air transport of dioxin. Although there are no significant sources of dioxin in Nunavut or within 500 kilometers of its boundaries, dioxin concentrations in Inuit mothers’ milk are twice the levels observed in southern Quebec. This is due to the elevated dioxin content of the indigenous diet—traditional foods such as caribou, fish and marine mammals."

The source of the air-borne dioxin produced by Chemetco's refining process was coated wire, including PVC-covered wire, plastics and computer parts. These were routinely used as part of the mix of grades of scrap copper used to charge the furnaces. Citing Buekens et al. 1997, an EPA report notes: "The presence of chlorinated plastics in copper scraps as a feed to smelters is believed to increase the CDD/CDF formation." (CDD's are dioxins and CDFs are polychlorinated dibenzofurans).

The ATSDR describes how "Because Chemetco had accepted material from a firm known to have dioxin contamination, USEPA investigated dioxin. On April 12, 1987, USEPA sampled an area of the Chemetco plant which was used to manage zinc oxide collected from the venturi scrubber system."

EPA testers found a dioxin concentration of 3.4 parts per billion. As a result, their toxological assessment unit ‘raised concerns about dioxins and furans in Long Lake sediments and the fish population.’ However, the ATSDR reports that these initial fears proved unfounded:

"In the summer of 1999, staff from the Illinois Department of Natural Resources and Illinois EPA collected fish samples from two sections of Long Lake. Buffalo and carp were collected closest to …the northern part of the lake where the illegal pipe discharged. Buffalo and crappie were collected from the southern section through Pontoon Beach. Fillet portions were analyzed for pesticides, polychlorinated biphenyls (PCBs), dioxins, and furans. No elevated levels of these chemicals were found."

This finding, in conjunction with those of Commoner et al. shows that Chemetco's dioxins were almost entirely released as smokestack emissions (also called flue gas stack) emissions.