MUSKEGON TOWNSHI, Mich. (AP) - An $8.1 million cleanup is planned at a western Michigan site used for military aircraft and tank engine manufacturing. The Muskegon Chronicle reports the 170-acre (69-hectare) site in Muskegon County's Muskegon Township is owned by military manufacturer L3 Technologies, but records indicate that the contamination occurred prior to the company's ownership. Court documents say contaminants include arsenic, cyanide, chromium, PCBs, lead and mercury. The newspaper says pollution has affected the site's groundwater and there are concerns about air quality. Contamination occurred between the 1920s and the mid-1990s. Under an agreement with the Michigan Department of Environmental Quality, L3 will cooperate with the cleanup conducted by former owner TDY, previously known as Teledyne Inc. The U.S. Department of Defense is expected to cover about $6.2 million of the cost. --- Information from: The Muskegon Chronicle, http://www.mlive.com/muskegon