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EPA Designates Four Corners Interstate Air Quality Region Boundaries

[EPA press release - February 9, 1971]

William D. Ruckelshaus, Administrator of the Environmental Protection Agency (EPA) today designated boundaries of Four Corners Interstate Air Quality Control Region, covering portions of Arizona, Colorado, New Mexico, and Utah. The region is described today in the Federal Register.

The Four Corners Interstate Air Quality Control Region includes Apache, Coconino, Navajo, Yavapai Counties in Arizona; Archuleta, Dolores, La Plata, Montezuma, and San Juan Counties in Colorado; San Juan County, in its entirety; portion of Rio Arriba County lying west (Pacific slope) of the Continental Divide; all portions of the Jicarilla Apache Indian Reservation lying east (Atlantic slope) of the Continental Divide; portion of Sandoval County lying west (Pacific slope) of the Continental Divide; portion of McKinley County lying west (Pacific slope) of the Continental Divide; portion of Valencia County lying within the Zuni and Ramah Navajo Indian Reservations, in the State of New Mexico; and Emery, Garfield, Grand, Iron, Kane, San Juan, Washington, and Wayne Counties in the State of Utah.

There are presently designated over 100 air quality control regions throughout the Nation, and it is anticipated that over 250 regions will have been designated by April 1, 1971.

The Administrator's action was taken under the 1970 Amendments to the Clean Air Act at the request of former New Mexico Governor David Cargo and Utah Governor Calvin Rampton. They requested that an air quality control region be designated in the Four Corners area.

As required by the Act, the Air Pollution Control Office of EPA held a consultation on November 19, 1970,* concerning proposed boundaries for the regions. Attending were representatives of the four States and of affected local agencies.

Under the Clean Air Act, as amended, the Environmental Protection Agency is required to publish air quality criteria for those pollutants harmful to health or welfare, and to publish reports on the techniques that can be employed to control the sources of those pollutants.

Criteria and technology reports for sulfur oxides and particulate matter were published on February 11, 1969. Equivalent reports for carbon monoxide, hydrocarbons, and photochemical oxidants were published on March 19, 1970, and for nitrogen oxides on January 30, 1971.

The criteria describe what is known of the effects of exposures to various concentrations of pollutants for various lengths of time. They provide the basis for the Administrator to develop and set Federal national primary air quality standards for the protection of public health and national secondary air quality standards for the protection of welfare in the designated air quality control regions. These standards, which were proposed on January 30, 1971, will become the goals of control efforts in the regions.

The control technology reports identify the best methods achievable for controlling the sources of the pollutants for which criteria are issued, whether those methods involve the application of control equipment, changes in fuel use or industrial process, or any other practical approach.

Under the Act, as soon as the Administrator has set the national primary and secondary air quality standards, the State or States responsible for a designated region are on notice to develop plans for implementing the standards within three years. The States are to conduct public hearings and submit their implementation plans for EPA approval within nine months after air quality standards have been established. The Administrator may grant a State an 18-month extension in the case of plans to implement secondary air quality standards.


* Prior to EPA's establishment in December 1970, the federal air pollution control function was the domain of the Department of Health, Education and Welfare's (HEW's) National Air Pollution Control Administration (NAPCA).