This law is contained in the 1990 Amendments to the United States Clean Air Act, and it is the primary reason why you should not remove or disconnect part of your car's emission control system or ask your automobile repair facility to do so in hopes of improving your car's gas mileage and driveability. If you or a repair facility break this law, a civil penalty of up to $2,500 may be imposed.

In addition to the law, there are other good reasons why tampering should not be done:

- in most cases tampering will not improve a car's gas mileage and driveability and may make them worse.

- the one sure result of tampering is that it will increase your car's emissions and add to air pollution.

- tampering is an expensive waste, nullifying emission controls that on a new model car cost you more than $475.

Another important point. The U.S. Clean Air Act now contains a prohibition against car owners tampering with their car's emission controls and most States also have such a prohibition. Therefore, you may also be prosecuted and fined under State law for any tampering that you do to a car's pollution controls.

This leaflet has been prepared by the U.S. Environmental Protection Agency to answer the questions that you are likely to ask concerning the new law. Please read it carefully. Your cooperation will help ensure that your car's pollution controls will continue to work properly and protect the air we breathe from pollution.

What is the Purpose of the Antitampering Law? The tampering prohibition was passed by Congress to make sure that cars in use retain emission control designs and functions that were built into them by their manufacturers. The law is necessary for reasons of public health. Motor vehicles contribute nearly one half of the total amount of man-made air pollution in this country. They emit nearly sixty percent of the total amount of the poisonous gas, carbon monoxide. They also emit one-fourth of the hydrocarbons and nearly one-third of the oxides of nitrogen, two major causes of the unhealthy smog that hangs over a great many of our cities and suburbs.

To protect the health of the American public, Congress established light-duty motor vehicle emission standards that have to be met by every new car sold in this country. Each manufacturer is required to certify that his design will enable the car to meet these standards for the length of its useful life.

Tampering, however, changes the car's certified design and causes the car to exceed emission standards. EPA surveys have shown tampering to be widespread. Some service and repair facilities have even claimed that the removal of emission controls will improve gas mileage. To stop practices the removal of emission controls to improve gas mileage. To stop practices like these and to make sure that cars in use continue to comply with emission standards throughout their useful life, Congress broadened the antitampering provision to cover all persons.

What Is New About the New Antitampering Law? The original prohibition against tampering contained in the Clean Air Act Amendments of 1970 applied to any person with respect to a new car before it is sold and delivered to the purchaser and only to manufacturers and car dealers with respect to sold cars. This law still applies to some 20,000 to 30,000 new car dealers, and violators are subject to civil penalties of up to $25,000 for each car tampered with.

The prohibition against tampering contained in the 1977 Amendments applied to any automobile services or repair facility and fleet operators. This tampering prohibition covers 300,000 to 350,000 motor vehicle repair facilities and several hundred thousand fleet operators. All repair facility owners, commercial mechanics, and fleet operators are prohibited from tampering. Violators of this provision of the law are subject to a civil penalty of up to $2,500 for each motor vehicle or motor vehicle engine tampered with.

-Now, the Clean Air Act Amendments of 1990 broaden the tampering provision to cover all persons. Everyone is now prohibited from tampering. Violators are subject to a civil penalty of up to $2,500 for each motor vehicle engine tampered with.

Can't Tampering Improve Gas Mileage and Driveability?

Evidence suggests that tampering can do little to improve gas mileage and driveability, and in many cases will worsen them. One reason for this is that the catalytic converter - the primary means after 1974 - has no negative effect on gas mileage and driveability. In fact, the catalyst has helped make it possible for cars with emission controls to achieve the same or even better gas mileage than cars had in 1967 before emissions controls were installed on cars. Thus, damaging or disconnecting a catalyst can only result in increased emissions and the waste of an expensive piece of equipment.

Emission controls are not simply stuck on a car in such a way that they can be harmlessly removed or maladjusted. Emission control is part of the total design and function of many components of a car's engine, including the fuel system, distributor, intake manifold, and EGR valve. When a mechanic changes the emission control design of one these components, he is also likely to affect its other functions, often adversely. Maladjustments of such parts, therefore, often result in loss of fuel efficiency as well as increased emissions.

In addition, fuel system adjustments, ignition timing, compression ratio, and EGR all affect an engine's durability.

Tampering can shorten an engine's life and cause performance problems at the same time.

Can Keeping a Car Well Tuned Help Gas Mileage and Emission Control at the Same Time?

Yes.

Maintaining you car according to the manufacturer's specifications will almost always enable your car to get better gas mileage and lower emissions. Studies of emissions inspection/maintenance programs show that cars failing the emission test get four to ten percent better gas mileage once their emission controls have been professionally serviced. In addition, keeping your car well tuned will almost always improve driveability and lengthen the life of your car's engine.

Can Tampering Void a Car's Warranty?

Yes.

Under the Clean Air Act, car manufacturers are required to provide warranties covering emission control systems and devices. However, when a car's emission controls have been tampered with, a car manufacturer may not be obliged to honor warranty rights. The car manufacturer or dealer can justifiably argue that the car has not been properly maintained according to the manufacturer's specifications.

What Can I Do to Help?

The emission controls installed on motor vehicles and motor vehicle engines are there to reduce the pollution from these sources to help meet national ambient air quality standards which were established to protect public health. The removal or rendering inoperative of these devices defeats a vital portion of the nation's program to clean up the air.

You can help clean the air by not tampering with your emission controls and not requesting to have your emission controls tampered with but instead, make sure the mechanic follows the specifications recommended by the manufacturer for best performance and emission control.

If you should learn of automobile service or repair facilities that have a policy of breaking the antitampering law, or have further questions, contact the Regional Office of the Environmental Protection Agency for your State, or the Field Operations and Support Division (EN-397F), Washington, D.C. 20460.

EPA Regional Offices are located in Boston, New York City, Philadelphia, Atlanta, Chicago, Dallas, Kansas City, Denver, San Francisco, and Seattle

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