COMPLIANCE INFO_2026 - Laserfiche WebLink

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Approximately 50,000 tons of waste were disposed of in the area that has been cordoned off since the March 5, 2026, load was received. On 4/22/2026 we communicated an update to Brendan Kenny which was the following: Following the initial anomalous report of 36 mg/kg mercury in a composite sample collected on February 23, 2026,the PUD conducted a further investigation.This investigation included a request for re-analysis of the original sample and the collection of new material for independent third-party verification.We have now received the final analytical results,which demonstrate that the sludge is non-hazardous and complies with all waste acceptance criteria. Analytical Findings and Verification 1. Re-analysis of Original Sample (WETLAB).WETLAB issued a second amended report on April 14, 2026, based on a re-analysis of the original composite sample (Sample ID 26020676-001). See attached.The re-analysis yielded a mercury concentration of 0.80 mg/kg(dry weight).This result is significantly below the California Total Threshold Limit Concentration (TTLC) of 20 mg/kg and federal RCRA hazardous waste thresholds.While the report includes a holding time (HT)flag reflecting the time elapsed before the re- analysis was initiated,this result is consistent with the PUD's 18-year history of non- detect or trace-level results. 2. Independent Third-Party Analysis (McCampbell Analytical).To further eliminate any uncertainty, the PUD collected a fresh composite sample from a current sludge shipment on April 9, 2026, and submitted it to McCampbell Analytical, Inc.The report dated April 16, 2026, confirms that mercury was non-detect(ND)with a reporting limit of 0.0500 mg/kg. See attached. Technical Analysis and Regulatory Compliance The weight of evidence supports the conclusion that the initial 36 mg/kg result was an analytical outlier or laboratory error rather than a representative measurement of the waste stream. • Matrix Stability: Mercury in a solid sludge matrix is physically stable.The exceedance of the recommended holding time for re-analysis would not reasonably account for a reduction from 36 mg/kg to 0.80 mg/kg. • Consistency:The amended result of 0.80 mg/kg and the subsequent non-detect result from an independent laboratory align perfectly with the generator's historical profile.