Does Missouri Have Emissions Testing?

Missouri maintains a vehicle emissions inspection program in the St. Louis metropolitan area to improve air quality and meet federal Clean Air Act requirements. The program, known as the Gateway Vehicle Inspection Program (GVIP), operates alongside Missouri's safety inspection requirements but applies only to designated geographic areas.

Understanding Missouri's Emissions Testing Program

The emissions testing program operates under the authority of Sections 643.300 to 643.360 of the Missouri Revised Statutes, which establishes the Air Quality Attainment Act. The Missouri Department of Natural Resources administers the emissions program through the Gateway Vehicle Inspection Program, while the Missouri Department of Revenue and the Missouri State Highway Patrol oversee safety inspections.

Which Counties in Missouri Require Emissions Testing?

Vehicle emissions inspections are currently required for vehicles registered in the following counties within the St. Louis metropolitan area:

• St. Louis City
• St. Louis County
• St. Charles County
• Jefferson County

Vehicles Subject to Emissions Testing in Missouri

Missouri's emissions inspection program applies to specific gasoline-powered vehicles based on model year, weight, and usage patterns. Understanding these requirements is essential for determining whether your vehicle needs testing.

Basic Requirements

According to the Missouri Department of Revenue, vehicles registered in the four designated counties must undergo emissions testing if they are:

• Model year 1996 or newer
• Gasoline-powered
• Have a manufacturer's gross vehicle weight rating (GVWR) of 8,500 pounds or less

Biennial Testing Schedule

Missouri uses a biennial (every two years) testing schedule based on vehicle model year:

• Even model year vehicles (2020, 2022, 2024, etc.) must be inspected during even calendar years
• Odd model year vehicles (2019, 2021, 2023, etc.) must be inspected during odd calendar years

Vehicles Exempt From Emissions Testing

The following vehicle categories are exempt from Missouri emissions inspections under Section 643.315, RSMo:

By Vehicle Type:

• Vehicles with GVWR over 8,500 pounds
• Motorcycles, motortricycles, and dirt bikes
• All trailers
• Heavy-duty diesel-powered vehicles over 8,500 pounds GVWR
• School buses and shuttle buses
• Vehicles displaying historic plates or street rod plates

By Power Source:

• Electric-powered vehicles
• Vehicles powered exclusively by hydrogen
• Plug-in electric drive vehicles (capable of operating solely on electric power)
• Vehicles powered by fuels other than gasoline, diesel, or ethanol (E10 and E85)

By Age and Mileage:

• New and unused vehicles during the model year and following year with less than 6,000 miles at first retail sale
• Model year 1995 or older (1996 or older if diesel-powered)
• Vehicles less than four years old with under 40,000 miles at first required biennial safety inspection (mileage-based waiver required)
• Vehicles driven fewer than 12,000 miles between biennial safety inspections (mileage-based waiver required)

By Ownership Transfer:

• Vehicles sold for junk, salvage, or rebuilding
• Vehicles sold from dealer to dealer

By Registration Status:

• Vehicles registered outside St. Louis City, St. Louis County, St. Charles County, and Jefferson County
• Vehicles receiving "title only" (no registration)

Emissions Testing Costs and Fees in Missouri

According to the Gateway Vehicle Inspection Program, the fees for Missouri vehicle inspections are:

Vehicles requiring both safety and emissions inspections may pay up to $36.00 total. The Missouri Department of Revenue establishes these maximum fees by regulation.

Reinspection Fees

Under Section 643.330, RSMo, vehicle owners are entitled to one free emissions reinspection if completed within 20 consecutive days of the initial failed inspection at the same station. After this period, or for subsequent reinspections, the full inspection fee may apply.

Where to Get Emissions Testing in Missouri

Missouri maintains authorized inspection stations throughout the four-county emissions testing area. Vehicle owners can locate facilities through the following resources:

Finding Inspection Stations

The Gateway VIP Station Locator provides a searchable directory of authorized emissions testing facilities by county or zip code.

Finding Repair Facilities

If your vehicle fails its emissions inspection, the Missouri Recognized Repair Stations Directory helps locate qualified repair facilities. These stations employ Missouri Recognized Repair Technicians who can:

• Diagnose emissions-related problems
• Perform necessary repairs
• Count labor and diagnostic costs toward cost-based waivers
• Provide detailed repair performance reports

Inspection Timing Requirements in Missouri

According to the Missouri Department of Revenue, vehicle emissions inspections must be completed:

• Before registering the vehicle with the Missouri Department of Revenue
• Not more than 60 days prior to the date of registration or registration renewal application
• Within 120 days prior if the inspection is provided by a licensed motor vehicle dealer at the time of sale

Registration Renewal Process

Missouri uses an integrated system where emissions inspection compliance is verified electronically during vehicle registration renewal. The process works as follows:

1. Complete required emissions inspection at an authorized station
2. Receive a Vehicle Inspection Report from the testing facility
3. Present proof of inspection (or verification occurs electronically) when renewing registration at your local license office
4. Pay applicable registration fees and receive updated registration

The Certificate of Inspection and Approval for safety inspections remains valid for 60 days, while emissions test results are valid for 60 days (120 days for dealer sales).

Special Provisions for Readiness Monitors

Missouri allows a 30-day grace period beyond the registration expiration date for vehicles that need additional driving to set readiness monitors for the on-board diagnostics (OBD) emissions test. The Gateway VIP website provides detailed information about readiness monitor requirements. However, the standard $5.00 late renewal penalty still applies if the registration expires.

Out-of-State Vehicles

New Missouri Residents:

New residents moving to Missouri and registering an out-of-state vehicle must comply with emissions testing requirements if registering in one of the four designated counties. According to the Missouri Department of Revenue, new residents have a grace period based on the biennial testing schedule:

• Vehicles with odd model years registered during even calendar years are temporarily exempt
• Vehicles with even model years registered during odd calendar years are temporarily exempt
• At the next required inspection cycle, the vehicle must undergo emissions testing

Temporarily Out-of-State Vehicles:

Vehicle owners whose vehicles are temporarily located outside of Missouri at registration renewal may register without an inspection by:

1. Completing a General Affidavit (Form 768) stating the vehicle has been out of state for at least 60 days
2. Having the vehicle inspected within 10 days of its return to Missouri
3. Providing proof that the vehicle was outside of Missouri during the registration renewal period

Out-of-Area Waiver:

Vehicles registered in emissions counties but based and operated outside the area for at least 24 months may qualify for an exemption. Owners must submit a notarized Out-of-Area Waiver Request (Form MO 780-2202) to the Missouri Department of Natural Resources.

Private Party Sales

All vehicles subject to emissions requirements must be inspected and approved prior to private sale or transfer. The inspection remains valid for 90 days after the date of sale.

Special Vehicle Considerations

Flex-Fuel, Dual-Fuel, and Hybrid Vehicles

According to the Gateway Vehicle Inspection Program, the following vehicles are subject to emissions testing:

• Flex-fuel vehicles burning biodiesel (B-5, B-20, B-100)
• Dual-fuel vehicles with gasoline or diesel fuel tanks
• Hybrid electric vehicles with gasoline or diesel engines

Pure electric vehicles remain exempt.

Switched Engine Vehicles

Vehicles with replaced or modified engines must undergo emissions testing even though the original manufacturer's certified engine configuration has been altered. These vehicles must:

• Have readiness monitors properly set
• Meet the original manufacturer's emissions criteria
• Bear full repair cost responsibility if the engine was improperly installed or incorrectly applied

There is no waiver for costs associated with improper engine installation or incorrect engine applications.

Gray Market Vehicles

Gray market vehicles (sold in another country and imported into the U.S.) are subject to emissions testing if they are:

• Gasoline-powered
• Have GVWR of 8,500 pounds or less
• Being licensed by the Missouri Department of Revenue Motor Vehicle Bureau

These vehicles are tested using the same emissions standards as vehicles sold in the United States. Importing vehicles that do not meet U.S. Environmental Protection Agency emissions standards violates federal law.

Contact Information

Missouri Department of Natural Resources - Inspection and Maintenance Unit
1390 Timberlake Manor Parkway, Chesterfield, MO 63017
Phone: (314) 416-2115
Official Website: Gateway Vehicle Inspection Program

Missouri Department of Revenue - Motor Vehicle Bureau
301 West High Street, Room 370, Jefferson City, MO 65105
Phone: (573) 526-3669
Official Website: Missouri Department of Revenue - Motor Vehicle Bureau

Missouri State Highway Patrol - Motor Vehicle Inspection Division
1510 East Elm Street, Jefferson City, MO 65101
Phone: (573) 751-3313
Official Website: Missouri State Highway Patrol - Motor Vehicle Inspection Division