Headspace gas chromatography was used to measure sorption equilibra between XAD-2, a styrene-divinylbenzene copolymer, and gaseous 1,2-dichlorobenzene (1,2-DiCB), 1,2,4,5-tetraechlorobenzene (1,2,4,5-TeCB) and hexachlorobenzene, (HCB), at temperatures above 40 degreesC. From the measurements, the sorption isotherms were constructed for the systems 1,2-DiCB/XAD-2, 1,2,4,5-TeCB/XAD-2, and HCB/XAD-2. It is shown that (a) capillary condensation within the mesopore structure of XAD-2 occurs at higher partial pressures; (b) the equilibrium data at relatively low partial pressures can be fitted to Freundlich isotherms; and (c) the sorption isotherms for the three compounds of interest are linear at very low partial pressures. Sorption coefficients at low partial pressures and 20 degreesC, extrapolated from the slopes of the linear isotherms obtained in the temperature range 90 degreesC to 130 degreesC, were (1.2 x 10(-6), 1.5 x 10(-5), and 1.6 x 10(-2)) mol(.m-2.)Pa(-1) for 1,2-DiCB/XAD-2, 1,2,4,5-TeCB/XAD-2, and HCB/XAD-2, respectively. This is in good agreement with values predicted using empirical models proposed in the literature.