The Western Processing site occupies approximately 13 acres in Kent, King County, Washington. Originally, Western Processing was a reprocessor of animal by-products and brewer's yeast. In the 1960s the business expanded to recycle, reclaim, treat and dispose of many industrial wastes, including waste oils, electroplating wastes, waste pickle liquor, battery acids, steel mill flue dust, pesticides, spent solvents, and zinc dross. Some of the Pacific Northwest's largest industries had contracts with Western Processing to handle their wastes. In March 1981, EPA inspected the site and found numerous RCRA violations. Further investigations found extensive contamination of soil, surface water and ground water both on- and offsite. This prompted EPA to issue a CERCLA Section 106 order in April 1983, requiring the owners/operators to cease operations immediately. Current investigations have found approximately 90 of the 126 priority pollutants in in the soil or ground water on and off the Western Processing site, or in Mill Creek.