Aftermarket Alternative Fuel Vehicle (AFV) Conversion Requirements
Conventional original equipment manufacturer vehicles altered to operate on propane, natural gas, methane, ethanol, or electricity are classified as aftermarket AFV conversions. All vehicle conversions for vehicles certified only to California Air Resources Board (CARB) standards must meet current applicable CARB standards for aftermarket conversions. However, U.S. Environmental Protection Agency (EPA) certified conversion kits may be used on EPA 50-state certified vehicles and vehicles with dual-certification that are 14,000 pounds or less.
(Reference Code of Maryland Regulations 26.11.34)