From the mass of regulations generated by the 1990 Amendments to the Clean Air Act (CAA) the increased use of methyl tert-butyl ether (MTBE) as an oxygen-enhancing additive in gasoline (intended to reduce carbon monoxide emissions) has been the result that produced the most widespread public response and the greatest amount of regulatory and legislative reshuffling. From local government in Fairbanks, Alaska to the State Senate of California to the Environmental Protection Agency citizens, legislators, regulators, and various commercial interests have been involved in a struggle to determine how best to protect the public interest as regards the use of MTBE, a likely human carcinogen that produces significant reductions in carbon monoxide emissions but is sometimes claimed to be an airborne health hazard and has been definitively shown to contaminate water supplies.
The CAA Amendments of 1990 were signed into law by President George Bush in November 1990. The overall goal of the amendments was to reduce polluting emissions from all sources by a total of 57 billion pounds per annum when full implementation was achieved in 2005. The primary thrust of the legislation was completion of efforts begun under the CAA of 1970 and its 1977 amendments. The amendments directed the EPA to establish regulations to achieve the various principal goals including: reducing urban air pollution, controlling emissions from mobile sources, reducing or eliminating other air toxins, reducing acid rain, and phasing out ozone-depleting chemicals. Overall the Amendments "made major changes in the way that air pollution is controlled in the United States" including the requirement that state and local air-quality authorities participate in designing local compliance plans.
The CAA had not been re-authorized in two decades and the passage of the Amendments came about because the Bush administration was able to persuade the EPA and proponents of the...