Air Quality

Clean Air Interstate Rule (CAIR)

The Clean Air Interstate Rule (CAIR) is a cap and trade program designed to reduce the amount of fine particulate matter and ozone that crosses state lines in the Eastern United States. CAIR caps emissions of nitrogen oxides and sulfur dioxide and sets up a market for facilities to trade emissions credits.

On July 11, 2008, the United States Court of Appeals for the District of Columbia Circuit (Court of Appeals) vacated CAIR (Case No. 05-1244) after finding "more than several fatal flaws in the rule." Because the United States Environmental Protection Agency (EPA) adopted CAIR as an "integral action," it was vacated in its entirety and remanded to EPA to promulgate a rule that was consistent with the Court of Appeals’ opinion. On September 24, 2008, EPA filed a petition for rehearing or, in the alternative, a remand of the case without vacatur. On October 21, 2008, the Court of Appeals issued a motion directing the parties of the case to file a response to EPA’s petition.

After considering the parties’ respective positions, the Court of Appeals decided to remand the case without vacatur on December 23, 2008. The Court of Appeals’ reasoning was that while CAIR was inherently flawed, allowing it to remain in place until EPA could promulgate another rule would at least temporarily preserve the environmental benefits that CAIR provides. Furthermore, the Court of Appeals decided not to impose a deadline by which EPA must correct the flaws within CAIR.

On May 1, 2009, the CAIR Program went into effect, replacing the NO_X SIP Call Program, in South Carolina.

In light of the decision to remand CAIR without vacatur, significant reductions in emissions of sulfur dioxide (SO₂) and/or nitrogen oxides (NO_X) from electric generating units through the State’s CAIR will be achieved. A co-benefit of CAIR will be reductions in mercury (Hg) emissions.

Detailed History of CAIR

EPA information on CAIR and the developments of this case

CAIR Permit Forms and Instructions

CAIR Documents

The information below includes Federal Register publications, South Carolina State Register publications, and other related materials to CAIR. If you have any questions, please contact Alan Hancock by phone at (803)898-4139 or by email.

All documents are in pdf format.