Laboratory testing was conducted to develop chemical resistance data using immersion tests. Six FML materials (polyvinylchloride, chlorinated polyethylene, chlorosulfonated polyethylene, high density polyethylene, epichlorohydrin and ethylene propylene diene terpolymer) were tested. Twenty chemical solutions providing a range of chemical challengers; acid and base, polar and non-polar, organic and inorganic, and increasing chemical concentration, were used. Duration of immersions were 1, 7, 14, 28, and 56 days, and four month increments for up to two years. All immersion tests were conducted at two temperatures, 23 deg and 50 deg C. Liners were evaluated for changes in appearance, weight, dimensions, and tensile properties. Procedures and criteria for evaluating immersion test results were developed using data from the study and comparing these data with comparable data from other studies, published reports and criteria, and liner manufacturer recommendations.