BackgroundThe Tomah Municipal Sanitary Landfill site is a former landfill operated by the City of Tomah from 1959 to 1979, when it closed out of concern for ground water quality. The landfill accepted both municipal and industrial wastes on an 18 acre portion of the property, located on Noth Street north of the intersection of Jefferson Street. Unlike the environmentally safe operations of today's landfills, wastes at the Tomah landfill were placed in shallow, unlined trenches, then covered with soil. When waste material became saturated with rain water, chemicals seeped into soil and ground water underneath the landfill. Ground water in the area of the Tomah landfill is flowing slowly to the north east, carrying with it landfill chemicals. The contaminated ground water, called a plume, is considered part of the site.
In addition to ground water contamination, harmful and explosive gas was created in the landfill as a result of decomposing waste. These gases moved through openings in waste and soil toward homes in a subdivision to the south of the landfill.
As a result of the contamination, EPA in 1989 placed the Tomah site on the National Priorities List, a roster of sites eligible for cleanup under the federal Superfund program. In 1995, a multi-year remedial investigation and feasibility study was completed by three parties that EPA holds responsible for the contamination, due to past association with the landfill. These parties - City of Tomah, International Paper and the Veterans Administration - studied ground water, soil, surface water, sediment (creek mud) and landfill gas and developed potential cleanup options for the site. After a public hearing and comment period, EPA signed a record of decision in 1997 for the landfill that formalized its decision to construct a landfill cap and install a gas extraction system.
In 2000, EPA oversaw the construction of the landfill cap, which is made of a thick synthetic membrane and several feet of clay. The cap was topped with a layer of soil and vegetation was planted. The cap prevents water from mixing with the waste and slows contaminant movement into underlying soil and ground water. In addition, a gas extraction system was installed to safely vent landfill gases into the air. Tests suggest these systems are working.
In September 2003, EPA signed a cleanup plan to address contaminated ground water. This plan, called a record of decision, relies on natural processes to clean ground water and includes the drilling of additional monitoring wells, regular monitoring of ground water, testing of Deer Creed and placement of land use restrictions to prevent use of ground water in contaminated areas.