In June 1975, the Forest Service Equipment Development Center at San Dimas, Calif., conducted tests to determine exhaust system temperatures on late-model vehicles. For normal operation, test results showed only small temperature differences at any point on a vehicle's exhaust system between those equipped with catalytic converters and those without catalytic converters. Also, test results indicate that the direct forest fire hazard from catalytic converter-equipped vehicles is essentially the same as with other exhaust systems, except when the vehicle engine malfunctions.NOTE: The term “vehicle,” as used in this report, refers to motor vehicles generally. “Automobile” or “car” implies a sedan, sedan delivery, or station wagon. A “pickup” is a pickup truck of less than 6,000 lb (2,721.6 kg) GVW.