Skip to content
Air Quality

Regional Haze

Haze is defined as visibility impairment caused by absorption and scattering of light by fine particles. Regional haze is caused by sources and activities that emit these fine particles over a large region, including areas of concern, such as national parks, forests, and wilderness areas ("Class I" Federal areas). Clean Air Act Section 169A mandates requirements to protect visibility, especially in Class I areas. The U.S. Environmental Protection Agency (EPA) first addressed visibility concerns in 1980, with the rule entitled "Visibility Protection for Class I Areas" (45 FR 80084, December 2, 1980).

In response to the Clean Air Act Amendments of 1999, the EPA finalized the Regional Haze Rule in 1999 (64 FR 35714, July 1, 1999). The rule calls for state, tribal, and federal agencies to work together to improve visibility in 156 national parks and wilderness areas, including the 21 Class I Wilderness areas. The states are required to develop and implement air quality protection plans (State Implementation Plans or SIPs) to reduce the pollution that causes visibility impairment. The Regional Haze Rule requires states to revise their SIPs to develop a plan to reduce visibility impairment so that by 2064, the visibility in the Class I areas will be returned to natural conditions.

Five multi-state regional planning organizations (RPOs) worked together to develop the technical basis for these state plans. The products of the RPOs were used by states to develop long-term (10 to 15 years) strategies for making "reasonable progress" toward eliminating all manmade visibility impairment from mandatory Class I areas. These strategies formed the basis for the SIP revisions.

With the help of the Visibility Improvement - State and Tribal Association of the Southeast (VISTAS) RPO, South Carolina developed a SIP revision in 2007 to address visibility impairment in the State's Class I Federal Area, the Cape Romain Wilderness Area, located on the coast of South Carolina. In developing this SIP revision, South Carolina has prepared a long-term strategy and examined the possible application of Best Available Retrofit Technology (BART) in order to establish reasonable progress goals for Cape Romain.

Many states' SIPs relied in part on the EPA's Clean Air Interstate Rule (CAIR) to achieve the visibility goals of the Regional Haze Rule. The U.S. Court of Appeals for the D.C. Circuit (Court) remanded CAIR to EPA in December 2008, and this remand has delayed EPA's approval of Regional Haze SIPs. This delay led to litigation, which EPA settled with a consent decree. Under the consent decree, EPA must take a final action on South Carolina's SIP by June 15, 2012. In August 2011, EPA proposed the Cross-State Air Pollution Rule (CSAPR) to replace CAIR. On June 7, 2012, EPA issued a final rule (77 FR 33642) that in part concluded that complying with CSAPR would meet the visibility goals of the Regional Haze Rule. The Court however vacated CSAPR on August 21, 2012. CAIR remains in place.

The Regional Haze Rule requires states to conduct a periodic review 5 years after submitting their original Regional Haze SIP submittal. These reviews update emissions projections in states’ original Regional Haze Plans, and demonstrate states are making reasonable progress to reducing visibility impairment. On December 27, 2012, DHEC submitted the 2012 periodic review as an amendment to the SIP.

The information below includes the proposed periodic review documents, Regional Haze SIP revision documents, Federal Register publications, and South Carolina State Register publications. If you have any questions, please contact Maeve Mason by phone at (803) 898-2230 or by email.

Regional Haze Documents

All documents are in pdf format.

2012 Periodic Review

Regional Haze State Implementation Plan


Federal Register Publications

State Register Publications

Supplemental Information

For more information please contact the Bureau of Air Quality at (803) 898-4123 or by email.