This exploratory experimental research project was conducted (1975-1983) to assess the relative effectiveness and durability of a wide variety of liner materials when exposed to hazardous wastes under conditions that simulate different aspects of service in on-land waste storage and disposal facilities. The materials studied included compacted soil, polymer-treated bentonite-sand mixtures, soil cement, hydraulic asphalt concrete, sprayed-on asphalt, and 31 flexible polymeric membranes based on polyvinyl chloride, chlorinated polyethylene, chlorosulfonated polyethylene, ethylene propylene rubber, neoprene, butyl rubber, elasticized polyolefin, and polyester elastomer. Four semicrystalline polymeric sheetings (polybutylene, low-density polyethylene, high-density polyethylene, and polypropylene), though not compounded for use as liners, were included in the study because of their known chemical resistance and use in applications requiring good chemical and aging resistance. The lining materials were exposed in test cells to 10 actual waste liquids, including two acidic wastes, two alkaline wastes, three oily wastes, a blend of lead wastes, a pesticide waste, and an industrial waste. The polymeric materials were also exposed to three media of known composition, deionized water, 5% aqueous solution of salt, and a saturated solution of low concentration (0.1%) of an organic, tributyl phosphate. The experimental approach and methodology followed are described. The polymeric materials were also exposed to wastes or environmental conditions under a variety of procedures which included primary one-side exposure, immersion-type testing, two types of outdoor exposure, and a pouch test. Some of the exposures were for as long as 2700 days. New methods for the testing of polymeric materials are presented.