Mailbag: CARB E.O. Numbers & Emissions-Legal Explained

You’ve got questions. We’ve got the answers—the Summit Racing tech department tackles your automotive-related conundrums. This week, we’re explaining the concept of emissions-legal.

Q: I recently got my hands on a late model 6.2L Camaro 1SS and plan on making some performance modifications. When shopping around for potential upgrades, I noticed certain products are marked as “50-state-legal “or “California-legal.” Can you explain what this means and how it applies to me? Also, some items come with a CARB E.O. number—what is the purpose of this number?

S.W. Frisco, TX

A: There are certain emissions standards that aftermarket parts must meet. These include federal/EPA mandates or California-specific emissions standards—it is up to individual states to decide which emissions rules to which they want to adhere. The California regulations, which are put forth by the California Air Resources Board (CARB), are more rigid than the federal regulations. These CARB regulations prohibit the sale or use of parts that will modify or defeat emissions systems in any 1965 and newer vehicle. This excludes true replacement parts and those granted an exemption (E.O.) number by the California Air Resources Board.

This is the CARB E.O. number you mention.

When purchasing parts for vehicles in states that use California emissions standards, you must use parts that come with a CARB E.O. number. One final note: more and more states have begun to adopt the California emissions standards, so you should always check your area’s emissions laws before making a purchase.