Safe for ozone action days. Converting small utility engines such as lawnmowers to burn propane instead of gasoline can reduce emissions of ozone precursors by one third and increase fuel economy by 14 percent (Cotton, 1992). According to the U.S. Environmental Protection Agency, a typical four-horsepower gasoline lawnmower engine generates almost six times as much volatile organic compounds (VOCs) per hour of use as a typical car. Clean enough to use indoors. LPG forklifts can reduce emissions of indoor and urban air pollutants, especially emissions of particulate matter compared to diesel and carbon monoxide compared to gasoline. “Overall, the urban air-quality benefits of LPG are similar to the benefits of CNG (generally considered the cleanest of the fossil-fuel alternatives.)” (Delucchi, 1999).