A 1966 compact van, converted to operate on LP-gas and evaluated under the federal exhaust emissions procedure, approached several definitions of a “pollution-free vehicle.” Specific pollutant results were as follows: 1. The hydrocarbon and carbon monoxide levels of 126 ppm and 0.3%, respectively, were below the 1968 and 1970 emission limits. 2. Certain LP-gas fuel system designs promise to eliminate all evaporative losses. 3. The exhaust hydrocarbons were 70% less reactive than those in gasoline exhaust. 4. Aldehydes, a highly reactive class of exhaust compounds, were low. 5. Oxides of nitrogen were significantly higher with LP-gas because of operation at maximum economy mixtures and maximum power spark advance. 6. The use of a catalytic muffler and rich LP-gas mixtures produced very low oxides of nitrogen levels with other pollutants below the 1968 limits.