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Show ----------------------------------------------------------------------------------------------------------------------- Table IV. Suppliers of Wood Fuel to Tacoma Steam Plant #2 Supplier Murray Pacific Olympic Simpson Paxport Skillman Fasano Redmoor Demolition #7 Edman Company Tebb Girard #10 Harbor Chipping Daily Relative Rank Approximate Level of Supply #1 > 10,000 tons #2 5,000 - 10,000 tons #3 2,500 - 5,000 tons #4 . 2,500 - 5,000 tons #5 1,000 - 2,500 tons #6 <1,000 tons <1,000 tons #8 <1,000 tons #9 <1,000 tons <1,000 tons #11 <1,000 tons #12 <1,000 tons Tests on all of the five largest suppliers of wood fuel failed to detect problematic levels of arsenic. Tests of wood from the Edman Company did, on occasion, demonstrate very high levels of arsenic. One such test indicated an arsenic concentration in the wood fuel of 54.5 ppmw. Given the concentration impacts when wood is combusted and the arsenic reports with the inorganic or ash material, a fuel concentration of 54.5 ppmw As could cause ash concentrations of arsenic well in excess of 100 ppmw. This arsenic could well have come in as A~03' because it was probably in the fonn of crushed slag resulting from copper smelting. When this test result was obtained, this vendor was no longer utilized by Tacoma Steam Plant #2. Tests of Redmoor Demolition Wood and Harbor Chipping are shown in Table V. These tests largely indicate that the demolition wood is free of high concentrations of arsenic; however some loads contain significant concentrations of this metal. Those same loads with significant concentrations of arsenic also have measurable concentrations of chromium, indicating the probable presence of wood treated with CCA, a compound composed of copper, chromium, and arsenic. Such wood is commonly used in the construction of decks and outdoor structures, and is also used as the interface between the foundation and the structure of a house. It is significant to note that the current fuel specification of Tacoma Public Utilities prohibits vendors from selling treated wood to the facility. |