On May 13, 2010, The EPA issued its final tailoring rule for greenhouse gas emissions. Beginning next January, facilities that must already obtain New Source Review permits for other pollutants will be required to include greenhouse gases in their permits if they increase their emissions of the gases by at least 75,000 tons of carbon dioxide equivalent per year.
On December 7, 2009 the Environmental Protection Agency finalized its Endangerment Finding, expanding their authority to regulate greenhouse gas emissions under the Clean Air Act. The new regulations require permits for carbon emissions; however, the current threshold of 250 tons of carbon dioxide is too low to be effectively enforced. In September 2009, the EPA proposed the "tailoring," or, "Big Polluters" rule to set a higher threshold of 25,000 tons of carbon dioxide and therefore limiting this requirement to the largest polluters in the U.S., facilities responsible for about 70% of the nation's greenhouse gas emissions. If approved, the proposal would require all stationary sources that emit 25,000 tons of carbon dioxide per year to obtain permits by using the best available control technologies and energy efficiency measures to minimize global warming pollution. Without the permits, these facilities will be unable to begin new construction or make modifications.
This rule establishes an equitable framework, by setting a regulatory threshold that holds the largest polluters accountable while protecting the nation’s schools, farms, and small businesses. The legality of altering the thresholds set by the Clean Air Act is currently under review and will greatly affect the United States' ability to curtail greenhouse gas emissions.
The EPA will complete another rulemaking by July 1, 2012, taking comment on phasing in additional sources and whether certain small sources can be permanently excluded from permitting requirements. Such a rulemaking would not require permitting for sources that emit less than 50,000 tons of greenhouse gases annually.