Solubility data are reported for ethyl phenyl sulfide (EPS) and 2-chloroethyl ethyl sulfide (CEES) in CO2 at temperatures from 25 to 100degreesC. These two sulfide-based compounds are homomorphs for chemical warfare agents (CWAs). Both sulfide-CO2 mixtures exhibit type-I phase behavior. The maximum in the 100degreesC isotherm is approximately 2600 psia for the CEES-CO2 system and approximately 3400 psia for the EPS-CO2 system. The Peng-Robinson equation of state (PREOS) is used to model both sulfide-CO2 mixtures as well as the phase behavior of the 2-chloroethyl methyl sulfide (CEMS)-CO2 system previously reported in the literature. The Joback-Lydersen group contribution method is used to estimate the critical temperature, critical pressure, and acentric factor for the sulfides. Semi-quantitative estimates of the phase behavior are obtained for the CEES-CO2 and EPS-CO2 systems with a constant value of k(ij), the binary interaction parameter, fit to the 75degreesC isotherms. However, very poor fits are obtained for the 2-chloroethyl methyl sulfide-CO2 system regardless of the value of k(ij). On the basis of the high solubility of EPS and CEES in CO2, supercritical fluid (SCF)-based technology could be used to recycle or recover chemical warfare materials. (C) 2003 Elsevier B.V. All rights reserved.