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On March 2, 1988, PHS-EHD signed a "Memorandum of Understanding" with the Department of Health Services (DHS) now known as Cal -EPA, Department of Toxic Substances Control (Cal-EPA/DTSC) authorizing PHS-EHD to perform hazardous waste generator inspections in San Joaquin County. V. GENERAL DESCRIPTION OF FACILITY: LIKA manufactures printed circuit boards of double sided and multilayer construction. The customers consist of manufacturers of electronic equipment. These customers include computer, telecommunications, medical, and other "Hi - tech" electronics manufacturers. LIKA is a 24-hour operation and has 244 employees, all of which are permanent and full time. Briefly, the manufacturing process consists of the following: All circuit boards begin as a fiberglass substrate covered in copper. For multilayered boards, they are laminated with a "light sensitive" photoplymer dry film. The film displaying the circuitry pattern is exposed to UV light to image the circuitry on the inner layer of the board. The board is then placed in a potassium carbonate bath that dissolves the photopolymer, thus uncovering the exposed pattern copper. This is followed by a 16% ammoniaenchant solution that serves to etch the unexposed copper. The board then goes through a series of baths for processing, including an acid soap cleaner to remove contaminants. The board is then baked to remove all moisture, layered in "books" using epoxy to laminate and pressed with 360 degrees heat and pressure. The single layer boards join the multilayered boards at this point for drilling. The multilayered boards must then go through an etchback process to remove smearing that occurs in drilling. All boards are then subjected to an electroless copper plating process to facilitate conductivity. Another dry film procedure, termed electrolytic copper process or "pattern plate", then takes place to image circuitry on the outer layer of the board. This is followed by another etching similar to the one described above. Other plating materials, such as gold or nickel, can be utilized depending on the specifications by a particular customer. The entire board is sprayed with a protective coating called solder mask. This is a preventive measure that deters possible shorting of the circuits due to dust build-up within the product or during repair of the product. The board is then dipped in 250 degrees molten solder. The solder serves two functions: first, to prevent oxidation of the copper and second, to allow the components to be more easily mounted to the board. Next, in fabrication, the board is cut to the required specification. Finally, the board goes through a series of testing in quality control to prepare the final product for shipping. LIKA also manages their own wastewater treatment operation in the rear of their facility. The wastewater (including mop water from the production floor) is fed into a series of tanks where sodium hydroxide is eventually added creating metal hydroxide solution to precipitate. The "metal free" solution goes through a pH adjustment and is then discharged to the sanitary sewer. The metal hydroxide particles are transferred to a filter press that performs mechanical dewatering.