Emissions & Environmental Notice

Performance parts and emissions law cross paths in ways that trip people up. Here is the straight version, so you buy the right part for where you drive and how you use your vehicle. This page is general information, not legal advice.

The short version

• Federal law prohibits tampering with or disabling the emissions equipment on any vehicle driven on public roads. That applies in all 50 states.
• California has the strictest aftermarket rules. Emissions-related parts generally need a CARB Executive Order (EO) number to be street legal on a California-registered vehicle.
• A number of other states follow California's emissions rules, and that list can change.
• Parts labeled "off-road use only" or "for competition use only" are not legal for vehicles operated on public roads.
• You are responsible for knowing and following the laws where you register and drive your vehicle.

Federal law applies everywhere

The federal Clean Air Act makes it a violation to tamper with or disable the emissions control systems on a vehicle operated on public roads. This applies in every state, regardless of whether your area has an inspection program. It is federal, and it does not go away just because a local shop does not check.

California and CARB

California regulates aftermarket emissions-related parts through the California Air Resources Board (CARB). For a part that affects emissions to be legal on a street-driven, California-registered vehicle, it generally must carry a CARB Executive Order (EO) number. An EO number means CARB tested the part and granted it an exemption for street use. Emissions-related parts without an EO number are typically labeled for off-road or racing use only in California.

We do not describe a part as "50-state legal" or "CARB legal" unless it carries a CARB EO number.

States that follow California

California is not the only state with these rules. A number of other states have adopted California's vehicle emissions standards, and their requirements can affect whether an aftermarket part is street legal. This area is changing and is currently the subject of legal challenges, so both the list of states and the force of these rules can shift. Do not assume a part is street legal in your state based on another state. Confirm your own state and local requirements before you buy.

Off-road and competition-only parts

Some parts we offer are labeled by the manufacturer for off-road use only or for closed-course competition only. That label is not a formality. It means the part is built for vehicles that are not driven on public roads, such as a dedicated race car or off-highway vehicle. Putting an off-road-only part on a vehicle you drive on the street can violate federal and state law, can cause you to fail inspection, and is your responsibility to sort out, not ours.

Your responsibility as the buyer

Emissions laws vary by state, by county, and sometimes by city, and they change over time. You are responsible for confirming that a part is legal for your vehicle, your use, and your location before you purchase and install it. If you are not sure, check with your state's emissions or motor vehicle authority, or reach out to us and we will point you to what the manufacturer states about the part.

How we flag these parts

We tag emissions-sensitive parts, such as tuners, off-road pipes, and catless components, and we surface their CARB status where the manufacturer provides it. When a part is not street legal in California or in states that follow California's rules, we tell you rather than leave you to find out at inspection. Straight answers are the whole point of shopping here.

A note on your factory warranty

Installing aftermarket parts can affect your vehicle's factory warranty in some situations. Under the federal Magnuson-Moss Warranty Act, a manufacturer cannot void your entire warranty simply because you installed an aftermarket part. It can, however, deny a specific claim if it shows that the part caused the failure. Keep your receipts and installation records in case you ever need them.

Questions

If you have a question about the emissions status or legality of a specific part, the manufacturer is the best source for its CARB status and intended use. Reach out and we will help you find the right answer before you buy.