The extent to which benzo(a)pyrene and other polynuclear hydrocarbons are emitted to the atmosphere from some of the more commonly occurring suspect sources is currently being evaluated in a source sampling study by the Public Health Service. A first step in this study was the development of a technique for collecting samples from high temperature combustion and process gas streams in a manner which would assure retention of the hydrocarbon materials of interest. This paper reports the findings of a series of tests conducted to develop suitable methods for cooling the gas samples, to establish temperature requirements for the collected sample during the sampling period, and to evaluate wet versus dry collection techniques. (Author)