Dioxins are a family of chemicals comprising 75 different types of dioxin compounds and 135 related compounds called furans. They are unintended by-products of certain industrial processes and also occur due to activities such as backyard burning of household trash, and natural events such as forest fires.
Dioxin contamination in the City of Midland is the result of airborne emissions from past waste management practices at Dow. Emissions released into the air from incinerators used in the early days of Dow's manufacturing operations contained dioxins, which ended up in the soil downwind of the plant.
Dioxin emissions from Michigan Operations decreased dramatically over the years as processes were modernized. In 1995, Dow committed to reducing dioxin emissions by 90%, which had already been greatly reduced from past operations that contributed dioxin to Midland soil.
Dow's rotary kiln incinerator now enables 99.999% efficiency in eliminating chemical emissions.
This process is entirely voluntary. Testing and remediation will only take place with the consent of property owners. Property owners will have the option to refuse access to their property. If property owners decide not to participate, funding will be set aside for Dow to complete the work at a later date.
No, all costs will be incurred by Dow.
Data previously collected in the Midland area was used to determine where sampling should be conducted. This initial area has been generally defined as the area closest to Dow's Michigan Operations site, north to Eastlawn Drive, west to Rodd Street and east to Waldo Avenue. A smaller area to the southeast of the intersection of Washington and Ashman Streets also will be sampled. The footprint of these areas will be refined as the program is implemented and more sampling information becomes available.
MDEQ is responsible for determining appropriate clean-up levels where corrective action is required, as part of the State's authorization to implement the federal Resource Conservation and Recovery Act (RCRA). This clean up level was developed by MDEQ, in accordance with U.S. Environmental Protection Agency-approved risk assessment procedures, and with input from EPA. Sampling data and bioavailability soil studies conducted in the Midland area were factored into the calculations.
No. Risks to human health from dioxins are based on exposure. The action level is based on more exposure than most people will experience. The EPA has said that a small amount of an individual's exposure to dioxin comes from soils. If you are concerned, the MDEQ has recommendations on how to minimize your exposure to contaminated soil.
Dow will work to return lawns and yards to their pre-remedy state. The plan for each property will depend on property-specific circumstances, and will be reviewed with each owner. Dow will conduct cleanup work to remove 12 inches of soil and replace it with new soil in a manner that will preserve mature trees. Dow will also seek to protect unique or ornamental features, whenever possible. Vegetation and plants affected by the removal process will be replaced. The intent will be to make this as easy as possible for homeowners.
Dow will work with property owners to maintain new lawns and plants until they are re-established. This may include installing water delivery systems, restoring existing irrigation systems, and paying for watering the lawn and new plants until vegetation is re-established.
Based on studies conducted, the contamination was generally found only in the top 12 inches so that was established as the depth of soil required to be removed and replaced to address the contamination without the need for further sampling.
Since the soils meet nonresidential cleanup criterion, they will be reused on the Michigan Operations site.
These are two different situations requiring very different solutions. The river and floodplain are being addressed through an agreement with EPA that was signed in January 2010. Dow continues to follow the EPA's systematic process of characterization and remediation on the river, segment by segment, as required in the agreement.
MDEQ and Dow understand that this plan will resolve the issue of soil contamination on residential properties in the final resolution area.