History of Dioxins and Furans in the Tittabawassee River

More than 95 percent of the "dioxin" measured by MDEQ (on a "toxicity equivalents" or TEQ basis) in the 116 samples are actually various types of furans (called congeners). Less than 2 percent are actually dioxin in the form of 2,3,7,8-TCDD.

The congener pattern with the very high percentage of furans is unlike any Dow production waste produced in the years since manufacturing process wastes have been monitored and treated. In fact, Dow’s original manufacturing processes, which were used between 1897 and 1915, could be the source of a high volume and high concentration chlorinated furan waste stream.

The original chlorine cells were used to produce chlorine in long shallow troughs made of local lumber that had been tarred. Workers used carbon sticks as both cathode and anodes. These carbon sticks were impregnated with paraffin. The use of petroleum products (e.g. tar and paraffin) would have provided a source of naturally occurring furans that could have been chlorinated during the manufacturing process. (Production information summarized from Campbell & Hatton, Herbert H. Dow – Pioneer in Creative Chemistry (1951)).

Why is this an issue now?
In June 2003, Dow received a 10-year license from the Michigan Department of Environmental Quality (MDEQ) to operate the Midland plant. Part of the permit requires Dow to look at the dioxin/furan situation "off-site" and to manage the situation to reduce or eliminate exposure, if possible. This is known as remediation.