Skip to Content
Questions or Comments:

El Paso: Carbon Monoxide History

Background and history of El Paso area compliance with the National Ambient Air Quality Standards (NAAQS) for carbon monoxide (CO).

The SIP files on this page are hosted by the Texas Records and Information Locator (TRAIL) web archive . If you need assistance with a file, please contact

El Paso CO Second 10-year Limited Maintenance Plan

On September 7, 2016, the commission adopted the  El Paso CO Limited Maintenance Plan SIP Revision (Non-Rule Project No. 2015-015-SIP-NR). This SIP revision satisfies Section 175A(b) of the federal Clean Air Act (FCAA), which requires states to submit an additional revision to the SIP eight years after the redesignation of any area to attainment. This SIP revision demonstrates continued maintenance of the CO NAAQS in El Paso for 10 years after the expiration of the initial maintenance period, from October 2018 through October 2028. On September 8, 2017, the EPA published final approval of the CO limited maintenance plan SIP revision ( 82 FR 42454 ).

El Paso CO Redesignation Request and Maintenance Plan

In January 2006, the Texas Commission on Environmental Quality submitted a CO Redesignation Request and Maintenance Plan SIP Revision for El Paso to the United States Environmental Protection Agency (EPA). El Paso was eligible for redesignation to attainment of the eight-hour CO NAAQS because there had been no monitored violations of the standard since 2001. The EPA published a direct final approval on January 23, 2007. However, before the comment period closed, the EPA received adverse comments and withdrew its final approval on March 26, 2007.

On January 30, 2008, the commission adopted a revision to the SIP modifying the existing maintenance plan for CO in El Paso. This revised maintenance plan replaced the maintenance plan submitted in January 2006, amending the previously submitted CO redesignation request. The EPA proposed approval of the redesignation request and maintenance plan and the associated motor vehicle emissions budget in the Federal Register ( 73 FR 45162 ) on August 4, 2008. The effective date of the approval was October 3, 2008.

CO Designation Under the 1990 Federal Clean Air Act (FCAA) Amendments

A portion of El Paso was designated moderate nonattainment for CO upon enactment of the FCAA amendments of 1990.

In September 1992, Texas adopted a SIP revision including a 1990 base year CO emissions inventory, the El Paso oxygenated fuels program, new source review provisions for major CO sources, and corrections to the existing vehicle inspection and maintenance (I/M) program. The state submitted to the EPA a completed emissions inventory on November 17, 1992, and a commitment to upgrade the existing I/M program on November 15, 1992. The EPA approved the CO emissions inventory and oxygenated fuels program of the complete El Paso CO SIP revision on September 12, 1994. In October 1993, the commission adopted a another SIP revision including contingency measures and an enhanced I/M program for El Paso.

Under moderate classification, El Paso was required to attain the NAAQS by December 31, 1995 or face possible reclassification to serious nonattainment. Dispersion modeling was conducted to demonstrate that El Paso would be in attainment of the CO NAAQS by December 31, 1995, based on U.S. emissions alone. An attainment demonstration was prepared in order to avoid the reclassification of El Paso to serious nonattainment for CO. This information was included in the September 13, 1995 SIP revision .

1978 El Paso CO Nonattainment Area Designation

The EPA designated much of downtown El Paso nonattainment for CO on March 3, 1978.

In a March 30, 1979 SIP revision , the TACB addressed CO emissions by stating that federal motor-vehicle control measures, along with an agreement on transportation planning with neighboring Ciudad Juárez in Mexico, would be sufficient to attain the CO standard by the December 31, 1982 deadline. The EPA gave final approval of these SIP revisions on March 25, 1980.

Despite implementing these controls, CO levels continued to measure above the NAAQS in El Paso after the December 31, 1982 attainment date. On February 24, 1984, the EPA notified the state of a call for additional SIP revisions to attain the CO NAAQS by December 31, 1987. On July 26, 1985, Texas adopted additional SIP revisions for CO in El Paso that included a vehicle parameter I/M program, but despite that revision, El Paso could not demonstrate attainment by the deadline.

On May 27, 1985, the Texas Legislature passed Senate Bill 725, authorizing the state to establish any other motor vehicle inspection programs required by federal law. In August 1986, Texas adopted a SIP revision for CO in El Paso to incorporate a vehicle idle emissions I/M program, with an estimated attainment date of December 31, 1987.

Comprehensive History of the Texas SIP

This SIP History gives a broad overview of the SIP revisions that have been submitted to the EPA by the State of Texas. Some sections may be obsolete or superseded by new revisions, but have been retained for the sake of historical completeness.