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We discuss each criterion in more detail below: Class II Levels for Metals Material that could potentially contain levels of metals above background is evaluated by a two-tier system. Initially total metal concentrations are evaluated for concentrations that exceed ten times the Soluble Threshold Limit Concentrations (STLC) limits specified in state regulations. In the event a particular metal exceeds this concentration, an STLC test is performed on the samples to determine whether soluble concentrations exceed state hazardous waste thresholds. Material exceeding hazardous thresholds is not accepted at the facility. The soluble test data is then evaluated to determine whether concentrations of the various metals exceed "designated levels" criteria established by the Regional Water Quality Control Board for the facility. These are (in mg/1): ■ Cadmium 0.05 ■ Chromium (VI) 0.5 ■ Copper 20 ■ Lead 1.5 ■ Mercury 0.02 ■ Nickel 1.0 ■ Zinc 200 These soluble levels are determined by a Waste Extraction Test or WET test. Soils with soluble metal levels above these thresholds and below the hazardous waste levels are identified and reported as Class II Soil at Forward Landfill. They are considered disposal in terms of the tonnage cap. Soils with soluble metal concentrations below these thresholds are used in the manner described in the first paragraph of this transmittal. There are no Class II levels established for other metals. That is, soils or other wastes with soluble levels of other metals up to hazardous levels would not be considered Class II wastes at Forward Landfill. These materials may be used beneficially throughout the facility as described above. BAAQMD Regulation 8, Rule 40 This regulation defines soils with organic contents greater than 50 ppm (parts per million) as "Contaminated Soil." This regulation is similar to the comparable San Joaquin Valley Unified Air Pollution Control District regulation (Rule 4651), which defines "Contaminated Soil" as "soil which registers 50 ppm, or greater, of VOC when measured as hexane at a distance of 3 inches above the surface, or soil containing VOC which has been identified for decontamination by the designated lead agency."