Compressed Natural Gas (CNG) Vehicle Aftermarket Conversion Requirements
Vehicles converted to operate on CNG must be inspected and certified in accordance with relevant safety standards by a CSA America-certified CNG Fuel System Inspector. The vehicle must also be tested to ensure that it meets emissions standards in the applicable county, or the county with the most lenient emissions standards if the vehicle is registered in a county without its own emissions standards. A person who performs a conversion must certify to the vehicle owner that the conversion does not tamper with, circumvent, or otherwise affect the vehicle's on-board diagnostic system, if applicable. A CSA America-certified CNG Fuel System Inspector must also inspect the vehicle every three years, or every 36,000 miles, and after a collision occurring at a speed greater than five miles per hour.
The Utah Division of Air Quality may develop programs to facilitate coordination between government agencies and the private sector regarding emissions and anti-tampering compliance testing, vehicle safety, and potential improvements in the air quality of the state.
(Reference Utah Code