A laboratory method has been developed to provide an estimate of the amount of hydrogen chloride gas that will form during incineration of a waste. The method involves incineration of a sample of the waste at 900 C in a tube furnace, removal of particles from the resulting gases by filtration at 250 F (120 C), collection of hydrogen chloride gas in a water-filled impinger, and measurement of the collected HCl as chloride using a standard ion chromatography/conductimetric detection method. Duplicate experimental runs were conducted with quartz and with INCONEL components in the incineration zone of the apparatus. The two materials gave quite different results, which indicates some surface phenomenon may be involved. Results with quartz components indicated that organochlorine is essentially completely converted to HCl. Very ionic inorganic chlorides (e.g., KCl and NaCl) formed little or no HCl when incinerated in zero grade air (3ppm water and 1 ppm total hydrocarbon) but gave large amounts of HCl (20-80% conversion) if the incineration atmosphere contained 2.4-5.0% water vapor, which contains hydrogen for HCl formation. Results with less ionic inorganic chloride (FeCl3) and with chlorine in a positive oxidation state (NaCl solution) indicated significant conversion to HCl, especially in the presence of hydrogen from water vapor. In all cases, the presence of water vapor increased the amount of HCl formed, but INCONEL was judged less suitable than quartz because INCONEL gave low recovery of organohalogen as HCl.