The paper gives results of a study of the generation of transient puffs resulting from the batch incineration of liquid waste into a 73 kW rotary kiln incinerator simulator. Liquid wastes investigated included toluene, methylene chloride, carbon tetrachloride, and No. 5 fuel oil. Transient puffs from these wastes were monitored using on-line measurements for FID measurable hydrocarbons, carbon monoxide, and integrated particulate filter loadings, although the suitability of any one of these indicators depended on the chemical nature of the waste involved. Study results show that puffs formed during transient conditions are generated easily, even with small quantities of wastes and with the kiln operating at 100% excess air.