The Michigan Department of Environmental Quality (DEQ) says it has reached an agreement with Dow Chemical to clean up to 1,500 residential properties in Midland, Mich., that are contaminated with dioxins.
In a related development, Dow says it is offering to buy approximately 50 homes and lots located within the industrial and commercially zoned area outlined in the cleanup agreement.
DEQ is proposing a site-specific dioxin “action level” of 250 parts per trillion for residential soils in Midland. The city is the site of Dow’s corporate headquarters and a manufacturing plant that polluted the area with dioxins from the late 1890s until the 1970s.
Studies have indicated that dioxin contamination of the soil downwind of the plant is a result of airborne emissions from Dow’s historic waste incineration activities. Various dioxins are contaminating the properties, a DEQ official tells C&EN. These include 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) and 1,2,3,7,8-pentachlorodibenzo-p-dioxin, the two most potent congeners, as well as the less toxic octochlorodibenzodioxin.
Under the agreement, Dow will devise a detailed work plan and submit it to the state for review in March. There will be a 45-day public comment period; DEQ will also hold a public hearing in April on Dow’s proposal.
DEQ says it developed the cleanup level of 250 ppt in accordance with Environmental Protection Agency-approved risk assessment procedures and with EPA’s input. Soil sampling in residential areas is expected to begin in June.
“This proposed plan represents tremendous effort by the many partners gathered to address Midland’s dioxin issue,” DEQ Director Dan Wyant says. “The proposal is just the beginning of the work that lies ahead.”
The total cost of the endeavor will not be known until it is determined how many of the 1,500 properties require cleaning and how much work needs to be done. Dow will cover all of the costs.
Property owners have until June 30 to decide whether to accept Dow’s offer to clean or buy their homes and lots, which are located in two areas close to the plant. The program will also offer relocation support for those who rent these homes, if the property owner participates in the program.
Owners who choose not to relocate will be offered testing and remediation of their properties, if necessary, according to Dow.
“We see this as an opportunity to address land use near our manufacturing site and give people still living in this industrial/commercial area the choice to move elsewhere,” says Rich A. Wells, vice president and site director for Dow’s Michigan Operations.
Dow has committed to purchase the 50 properties but has not set aside a specific dollar amount, a company spokesman tells C&EN.
The announcement of the deal came just a day before EPA released an assessment of noncancer health effects of exposure to TCDD (see page 5).