Dow Chemical on Wednesday was ordered to clean up dioxin in homes and yards downstream of its Michigan headquarters, the result of dumping dioxin-laden chemicals in nearby rivers for decades. Test results revealed yesterday show dioxin levels in and around a number of houses some 20 miles downstream exceed by a few times the level considered reasonably safe by the U.S. EPA. Dioxin levels in the tainted yards averaged twice the safe limit; one yard sample was found to exceed safe levels by some 23 times. Dioxin is carcinogenic and extremely toxic, though Dow contends dioxin-laced soil doesn’t threaten people or animals. Previously, efforts by Michigan to get Dow to clean up its mess resulted in weak mitigation measures like spreading woodchips over contaminated soil. Former EPA official Mary Gade, who was allegedly forced out of her job following pressure from Dow, took a more aggressive stance on cleanup that yesterday resulted in EPA’s order to clean up the dioxin.