Audit standards consisting of volatile and semivolatile organics have been established by the EPA to be provided to federal, state, and local agencies or their contractors for use in performance audits to assess the accuracy of measurement methods used during hazardous waste trial burns. The volatile organic audit standards currently total 29 gaseous organics in 5, 6, 7, 9, and 18-component mixtures at part-per-billion (ppb) levels (1 to 10 000 ppb) in compressed gas cylinders in a balance gas of nitrogen. The semivolatile organic audit standards currently total six organics which are spiked onto XAD-2 cartridges for auditing analysis procedures.
Studies of all organic standards have been performed to determine the stability of the compounds and the feasibility of using them as performance audit materials. Results as of July 1987 indicated that all of the selected organic compounds are adequately stable for use as reliable audit materials.
Performance audits have been conducted with the audit materials to assess the accuracy of the measurement methods. To date, 160 performance audits have been initiated with the ppb-level audit gases. The audit results obtained with audit gases during hazardous waste trial burn tests were generally within ±50% of the audit concentrations. A limited number of audit results have been obtained with spiked XAD-2 cartridges, and the results have generally been within ±35% of the audit concentrations.