Audit materials containing Principal Organic Hazardous Constituents (POHCs) have been developed by AREAL for use by federal, state, and local agencies or their contractors to assess the accuracy of measurement methods during RCRA trial burn tests. Audit materials are currently available for 27 gaseous organics in 5, 6, 7, and 9 component mixtures at parts-per-billion levels (7 to 10,000 ppb) in compressed gas cylinders in a balance gas of nitrogen. The criteria used for the selection of the gaseous organic compounds is described. Stability studies indicate that all of the organics tested (with the exception of ethylene oxide and propylene oxide below 10 ppb levels) are stable enough to be used as reliable audit materials. Subsequent to completion of the stability studies, 129 performance audits have been initiated with the audit materials to assess the accuracy of the Volatile Organic Sampling Train (VOST) and bag measurement methods during or prior to RCRA trial burn tests.