The Pentagon intends to challenge Wisconsin in regulating all forms of the explosive dinitrotoluene (DNT), Army officials announced on Monday. Wisconsin is the first state in the nation to establish health-based guidelines for the pervasive military toxin that has contaminated groundwater and dozens of private wells near the Badger Army Ammunition Plant.
At a public meeting this week, local Army officials said that they have asked the Under Secretary of the Army for Environment, Safety, and Occupation Health to help contest health-based guidelines issued by the Wisconsin Division of Public Health and the anticipated adoption of drinking water and groundwater regulations by the Wisconsin Department of Natural Resources for certain isomers of DNT.
The Army is challenging an interim Health Advisory Level published by the Wisconsin Division of Public Health earlier this summer. The advisory, which was drafted by the agency’s senior toxicologist, recommends that the summed concentrations of all DNT isomers should not exceed 0.05 parts per billion (ppb) in drinking water. The recommended threshold also serves as an interim groundwater standard for Wisconsin.
In order to be protective of infants and children, CSWAB maintains that safe drinking water guidelines for total DNTs should be even lower than those proposed by the Wisconsin Division of Health. Federal environmental law currently requires an additional 10-fold margin of safety when there is limited information about health risks associated with pre- and post-natal exposures, as is the case with DNTs.
DNT is a highly toxic chemical mixture that is used in the manufacture of munitions. It is most commonly found as a mixture of six (6) isomers of DNT. Wisconsin has drinking water standard for the two isomers of DNT (2,4-DNT and 2,6-DNT). The acceptable threshold for both is 0.05 ppb.
Standards for the remaining four isomers of DNT have not been established by Wisconsin or any other state. The U.S. Environmental Protection Agency has not established a drinking water standard either.
Wisconsin seeks to regulate the less common forms of DNT which have tainted dozens of drinking water wells near the Badger plant, affecting rural families in the townships of Merrimac, Sumpter, and Prairie du Sac. Without a standard, the State is extremely limited in its ability to require the Defense Department to clean up groundwater and nearby residential wells.
The Pentagon recognizes that Wisconsin is setting a national precedent that could not only result in additional cleanup requirements at the Badger plant but could also prompt re-examination of cleanups at hundreds of other similarly contaminated military sites.
- Technical grade DNT is a mixture composed of approximately 76% 2,4-DNT, 19% 2,6-DNT, and 5% other DNT isomers (3,4-DNT, 2,3-DNT, 2,5-DNT, and 3,5 DNT). In groundwater and drinking water, however, these isomers can be found independently and in different ratios.
- At the Deterrent Burning Grounds, a hazardous waste site at Badger Army Ammunition Plant, the concentration of 3,4-DNT in groundwater is currently 3.98 ppb and 2,3-DNT concentrations are 1.16 ppb. The total concentrations of these less common isomers are more than 100 times the safe drinking water guidelines recommended the Wisconsin Division of Public Health. By comparison, 2,4-DNT and 2,6-DNT are both found at levels less than 0.05 ppb in the same groundwater monitoring well.
- In Wisconsin, the 2,3-DNT isomer has been detected in 103 groundwater and private water wells at concentrations as high as 2,200 ppb. The 3,4-DNT isomer has been detected in 37 wells at levels as high as 419 ppb. The 3,5-DNT isomer has been detected in 20 wells at concentrations as high as 23.9 ppb and the 2,5-DNT isomer has been detected in wells at concentrations as high as 1.5 ppb.
- In northern Wisconsin, the E.I. DuPont de Nemours & Co. ran the DuPont Barksdale Explosives Plant from 1905 to 1971. The company produced TNT, dynamite and other explosives for the military during World Wars I and II, and for the mining industry. Starting in 1997, tests found residues of explosive chemicals in 17 drinking water wells located between the site and Lake Superior. Two forms of dinitrotoluene (DNT) found in private well water were above the State of Wisconsin groundwater standard.