California Air Resources Board

The 1990 amendments to the Clean Air Act preempted CARB's control of emissions for new farm and construction equipment under 175 horsepower. The U.S. EPA has the sole authority to establish emission standards for these preempted engines used in new farm and construction equipment under 175 horsepower. See 13 CCR 2420(a)(1).  

However, if a manufacturer voluntarily certifies their preempted engines with California then those engines will be subjected to California emission standards. In addition, preempted engines maybe be subjected to CARB's In-Use Off-Road Vehicle Regulations which targets diesel particulate matter (PM) and oxides of nitrogen (NOx) emissions from In-Use (existing) Off-Road Heavy-Duty Equipment, and hydrocarbons (HC) and NOx emissions from In-Use Large Spark-Ignition (LSI) Engine Forklifts and Other Industrial Equipment.

For more information, please refer to CARB's In-Use Off-Road Vehicle Regulations pages for in-use off-road diesel vehicles and in-use LSI fleet requirements.  

Below is a description of applications for determining preempted equipment. Please also see information regarding the federal non-road engine emissions control program.

Equipment types with engines less than 25 horsepower are presumed not to be construction or farm equipment, with the exception of the following equipment types, which have been determined to be construction or farm equipment (not subjected to certification):

Equipment types with engines 25 horsepower or greater are presumed to be construction or farm equipment, with the exception of the equipment types listed below, which have been determined not to be construction or farm equipment (subjected to certification):

• Aircraft Ground Power
• Baggage Handling
• Forklifts that are neither rough terrain nor powered by diesel engines
• Generator Sets
• Mining Equipment not otherwise primarily used in the construction industry
• Off-Highway Recreational Vehicles
• Other Industrial Equipment
• Refrigeration Units less than 50 horsepower
• Scrubbers/Sweepers
• Tow/Push
• Turf Care Equipment