EPA has granted California a Clean Air Act preemption waiver giving the state the ability to enforce its own GHG standards for new motor vehicles beginning with the 2009 model year. The decision is based on EPA's reconsideration of an earlier denial of the request. The granting of the waiver has the effect of allowing the State of California to impose its own standards on motor vehicles rather than enforcing the nationwide federal standards. The Clean Air Act gives EPA the authority to allow California to adopt its own emission standards for motor vehicles due to the seriousness of air pollution in California. The government's rationale is explained in its July 8, 2009, Federal Register notice. The U.S. Chamber of Commerce has teamed with the National Automobile Dealers Association to ask a federal appeals court to review the waiver.