EPA Issues "Significant Deterioration" Regulations

[EPA press release - November 27, 1974]

Russell E. Train, Administrator of the Environmental Protection Agency, today issued final regulations for preventing "significant deterioration" of air quality in areas where the air is already cleaner than required by Federal standards.

The regulations, which were proposed on August 27, 1974, provide for a threefold classification plan, to be put into effect by the States, subject to EPA review. The regulations require public participation on determining which areas will maintain pristine air quality and which will be subject to planned development that does not cause significant deterioration of air quality. In no case will an area's air quality be allowed to exceed the Federal primary and secondary standards which protect the public health and welfare.

"These regulations provide an appropriate means for carrying out the public's desire to safeguard the important and widespread areas of clean air that our nation is fortunate to have," Train said. "They encourage, but do not dictate, State land use decisions within a framework that supports the goal of clean air preservation."

The classification plan is:

  • Class I designation involves those areas where almost no change from current air quality is allowed.

  • Class II designation indicates areas where moderated change is allowed but where stringent air quality constraints are nevertheless desired.

  • Class III designation indicates areas where substantial industrial or other growth is allowed and where increases in concentrations up to the national standards would be insignificant.

The Class I and II designations involve numerical limitations on the allowable increases in sulfur oxides and particulate matter concentrations over current levels. The numerical standards, expressed in micrograms per cubic meter of air, are attached.

Train stated that the regulations do not apply to the "automotive" pollutants--carbon monoxide and hydrocarbons--because of substantial progress bing accomplished by automotive emission controls and because of the difficulty in implementing further restrictions. Train said, however, that EPA "is soliciting additional comment and will modify the regulations later, if workable procedures can be developed."

All areas of all States will be initially designated Class II, except those countries or other comparable areas that already violate the Federal secondary standards. The classification requirements will not apply to those areas which presently have polluted air. They will remain subject to the Clean Air Act's existing requirements for cleaning up in order to meet ambient standards.

The States may propose to re-designate Class II areas to Class I or III--provided that they follow certain public participation procedures. These include a public notice and at least one public hearing in or near the affected area. In addition, EPA will publish proposed re-designations in the Federal Register for 30 days comment. Final approval of a re-designation will be made by EPA.

The final regulations have broadened the scope of the public hearing on a proposed re-designation: The hearing record must include a detailed social, environmental and economic analysis of the impact of the reclassification both on the areas proposed for reclassification and the surrounding areas and States, as well as a justification for wanting to reclassify an area.

Train said, "This provision will give us a better basis for determining whether a proposed re-designation should be disapproved as arbitrary and capricious."

The final regulations have also been strengthened in this respect: the requirement for a preconstruction review of new or expanded facilities of 18 types of industry has been extended to Class III areas as well as Class I and II. The review will apply to facilities whose construction or modification begins on or after June 1, 1975. The review is designed to insure that emissions from the facilities will not violate the allowable deterioration increments and that "best available control technology" is employed.

Sintering plants have been removed from the proposed list of 19 industry categories since they are a part of the iron and steel and other heavy metals industries that are already subject to the preconstruction review. Thus, sintering plants will be examined along with other facilities of these industry categories. A complete list of these industries is attached.

Train said the Class II designation would normally permit the construction of new coal-fired power plants, employing best available controls, with capacities ranging up to approximately 1000 megawatts, which is the average size of new power plants proposed for construction. The average size of existing plants is only 300 megawatts.

"We rejected suggestions that we double the Class II increment to allow for the construction of larger power plants and other heavy industrial facilities," Train said. "This type of expansion should be permitted only in conjunction with a conscious and approved decision to re-designate an area Class III."

The final regulations contain a new provision for dealing with interstate disputes over one State's proposed re-designation of an area which will affect another State: EPA will resolve disputes that States cannot settle among themselves, taking into account all relevant State, regional and national interests.

The proposed regulations have been modified to provide States more authority over Federal and Indian lands located in their States. Under the final regulations, Federal lands are subject to State designations except that federal land managers of national parks, forests, and other areas may reclassify them to a cleaner designation. In addition, Indian lands are subject to State re-designations in cases where States now exercise authority for environmental protection. Otherwise, re-designations will be up to the official Indian governing body.

The final regulations stem from a May 30, 1972 decision by the U.S. District Court for the District of Columbia, in a lawsuit brought by the Sierra Club, interpreting the Clean Air Act as requiring the prevention of significant deterioration of air quality in all clean air areas of the country. That decision was affirmed by the Supreme Court on June 11, 1973.

The final regulations will appear shortly in the Federal Register.

18 New Source Categories

Listed below are the 18 categories of new or expanded stationary sources which would be reviewed by the States, prior to construction, to insure that "best available" emission controls will be installed and that clean air will not be "significantly deteriorated."

  1. Fossil-Fuel Fired Steam Electric Plants of more than 1000 million B.T.U. per hour heat input.

  2. Coal Cleaning Plants (thermal dryers).

  3. Draft Pulp Mill Recovery Furnaces.

  4. Portland Cement Plants.

  5. Primary Zinc Smelters.

  6. Iron and Steel Mill Metallurgical Furnaces.

  7. Primary Aluminum Ore Reduction Plants.

  8. Primary Copper Smelters.

  9. Municipal Incinerators capable of charging more than 250 tons of refuse per day.

  10. Sulfuric Acid Plants.

  11. Petroleum Refineries.

  12. Lime Plants.

  13. Phosphate Rock Processing Plants.

  14. By-Product Coke Oven Batteries.

  15. Sulfur Recovery Plants.

  16. Carbon Black Plants (furnace process).

  17. Primary Lead Smelters.

  18. Fuel Conversion Plants.

Allowed Pollutant Concentration Increases
(Over Baseline)--Micrograms Per Cubic Meter
Pollutant Area Designation Applicable
Class I Class II
Particulate Matter
Annual Geometric Mean 5 10 75 (P)
24-Hour Maximum 10 30 150 (S)
Sulfur Dioxide
Annual Arithmetic Mean 2 15 80 (P)
24-Hour Maximum 5 100 365 (P)
3-Hour Maximum 25 700 1300 (S)
Note: Class III areas are limited to concentrations no greater
than the National Ambient Air Quality Standards.

(P)-Primary Standard
(S)-Secondary Standard