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About DHEC

Greenhouse Gas Emissions & Climate Change

Legal History and Regulatory Background

On April 2, 2007, the U.S. Supreme Court ruled that greenhouse gas (GHG) emissions, including carbon dioxide (CO2), fit the definition of an "air pollutant" under the Clean Air Act (Massachusetts v. EPA). The Court directed the EPA to determine whether or not GHG emissions from new motor vehicles cause or contribute to air pollution which may reasonably be anticipated to endanger public health or welfare, or whether the science is too uncertain to make a reasoned decision.

On December 15, 2009, the EPA published two major findings regarding GHG emissions:

  • Endangerment Finding: the EPA found that current and projected atmospheric concentrations of six (6) well-mixed GHG emissions – carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), hydrofluorocarbons (HFCs), perfluorocarbons (PGCs), and sulfur hexafluoride (SF6) – threaten the public health and welfare of current and future generations; and
  • Cause or Contribute Finding: the EPA found that the combined emissions of these well-mixed GHG emissions from new motor vehicles and new motor vehicle engines contribute to GHG pollution which threatens public health and welfare.

On April 1, 2010, the EPA finalized the light-duty vehicle rule geared at reducing GHG emissions from light-duty cars and trucks starting with the 2012 model year vehicles. Once a new pollutant becomes "subject to regulation" under the Clean Air Act for mobile sources, air permitting requirements for stationary sources are automatically triggered. Consequently, the light-duty vehicle rule automatically triggered air permitting requirements for major industrial and commercial facilities and plants nationwide.

The major source thresholds under the Clean Air Act are currently 100 or 250 tons per year, depending on type source, for stationary sources for criteria pollutants, such as particulate matter (PM), sulfur dioxide (SO2), carbon monoxide (CO), and nitrogen oxide (NOx). Since GHG emissions are emitted in much larger quantities than traditional criteria pollutants, the EPA admitted that these current major source thresholds were clearly not designed to apply to GHG emissions.

On May 13, 2010, EPA finalized the GHG Tailoring Rule. This rule redefined the major source thresholds for GHG emissions to be 100,000 tons per year under the Prevention of Significant Deterioration (PSD) program for construction permits and the Title V program for operating permits. The GHG Tailoring Rule also provided a phased approached for requiring more facilities to become subject to new GHG permitting requirements over time, and to potentially require smaller businesses to become subject to GHG permitting requirements after 2016. South Carolina's Legislature passed Joint Resolution H 4888 (signed by Governor Sanford on June 11, 2010) to give SCDHEC authority to implement the EPA's GHG Tailoring Rule at the 100,000 tons per year major source threshold.

Under the Clean Air Act, major sources are also required to install the best available control technology (BACT) to reduce emissions prior to operating a new source. Currently, there are no commercially available control technologies for reducing GHG emissions. There is significant on-going research of carbon capture and underground storage technologies for GHG emissions. However, the EPA admits this technology is currently too expensive and not technically feasible for the vast majority of facilities. Additionally, the long term impacts of underground storage are unknown. Therefore, the BACT review for most new sources of GHG emissions will result in no additional control technology or emissions reductions. Energy efficiency assessments are the only control alternative the EPA is currently recommending for BACT reviews. However, often when reduction measures are put in place to reduce GHG emissions (i.e, fuel switching, equipment replacement, etc.) criteria pollutant emissions can sometimes increase and potentially interfere with maintaining the National Ambient Air Quality Standards (NAAQS).

As a result of EPA's two major findings and subsequent regulatory actions to reduce GHG emissions under the Clean Air Act, many states, industry groups, and conservation organizations have filed petitions and lawsuits against the EPA. Congress has also introduced many bills and resolutions that if passed would strip EPA's authority to regulate greenhouses gases, force a 2-3 year delay of EPA's programs, or let Congress establish the national climate change policy for the United States.

South Carolina Air Permitting Impact

It takes approximately 6-9 months for SCDHEC staff to issue most construction permits for new major sources in South Carolina. This timeframe includes administrative and technical reviews of the application and permit preparation, EPA draft permit reviews, and opportunities for public comment, public meetings and hearings. We expect the uncertainty and complexity of the new GHG BACT review process to add additional delays before a permit decision can be made. The number of facilities affected by these new requirements and the staff resources needed to implement this new program are difficult to predict and currently unknown at this time.

More Information

More information about GHG emissions can be found at SCDHEC's Greenhouse Gas Emissions webpage at, and at EPA's Climate Change webpage at