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Pacific Southwest, Region 9

Serving: Arizona, California, Hawaii, Nevada, Pacific Islands, Tribal Nations

Air Actions, Nevada

NOTE: This content is no longer being updated. The most up to date information can be found in Federal Register Notices and Approved Air Quality Implementation Plans in Region 9.

Finding on Las Vegas Carbon Monoxide Plan

August 31, 1999


Final Rule Making a Finding of Failure to Submit a Required State Implementation Plan for Carbon Monoxide for Clark County SUMMARY OF ACTION This is an objective finding based solely on the lack of a SIP submittal.

Carbon monoxide is chemical compound that is colorless, odorless, tasteless, and is a extremely poisonous gas that is less dense than air under ordinary conditions. You can't see or smell carbon monoxide. When air containing as little as 0.1% carbon monoxide by volume is inhaled, the oxygen carried by hemoglobin is replaced by the carbon monoxide, resulting in fatal oxygen starvation throughout the body. More than 3,000 children 14 years of age and under are treated for carbon monoxide poisoning in hospital emergency rooms each year in the US. Nationwide, two-thirds of the carbon monoxide emissions come from transportation sources, with the largest contribution coming from highway motor vehicles. In urban areas, the motor vehicle contribution to carbon monoxide pollution can exceed 90 percent.

EPA is taking final action in making a finding, under the Clean air Act (CAA or Act), that Nevada failed to make a carbon monoxide (CO) nonattainment area state implementation plan (SIP) submittal required for the Las Vegas Valley under the Act. Under certain provisions of the Act, states are required to submit SIPs providing for, among other things, reasonable further progress and attainment of the CO national ambient air quality standards (NAAQS) in areas classified as serious. The deadline for submittal of this plan for the Las Vegas Valley was May 3, 1999.

This action triggers the 18-month time clock for mandatory application of sanctions and 2-year time clock for a federal implementation plan (FIP) under the Act. BACKGROUND The Las Vegas Valley area, was designated nonattainment by operation of law upon enactment of the 1990 Amendments. CO areas with design values between 9.1 and 16.4 parts per million (ppm), such as the Las Vegas Valley area, were classified as moderate.

States containing areas that were classified as moderate nonattainment by operation of law were required to submit SIP's designed to attain the CO NAAQS as expeditiously as practicable but no later than December 31, 1995. Nevada requested and EPA granted a one year extension of the December 31, 1995 attainment deadline to December 31, 1996. However, in the first quarter of 1996, Clark Co. recorded three exceedances of the CO standard at the East Charleston monitoring station. Clark County challenged the validity of the CO data collected at this site. EPA stated it would not disqualify the January to March winter 1996 CO season monitoring data from the East Charleston station without conclusive evidence that it was inaccurate. Therefore Region 9 worked with Clark County and State of Nevada to properly site and approve a new monitoring site at Sunrise Acres, and worked collaboratively with the State and Clark County to examine whether East Charleston levels correlated with Sunrise Acres (the East Charleston replacement site) levels. Data received for the new Sunrise Acres monitor tracked closely with historical data from East Charleston. As a result of that finding, the Las Vegas Valley, Nevada CO nonattainment area was reclassified as serious. The State had 18 months or until May 3, 1999 to submit a new SIP demonstrating attainment of the CO NAAQS as expeditiously as practicable but no later than December 31, 2000, the CAA attainment date for serious areas. The Las Vegas Valley continues to exceed the CO standard with 1 exceedance in 1997 and two in 1998.

Notwithstanding significant efforts by the Clark County Department of Comprehensive Planning to complete their CO SIP, the State has failed to meet the May 3, 1999 deadline for the required SIP submission. EPA is therefore compelled to find that the State of Nevada has failed to make the required SIP submission for the Las Vegas Valley. The CAA establishes specific consequences if EPA finds that a State has failed to meet certain requirements of the CAA. If Nevada has not made the required complete submittal by 18 months after the signing of the Notice, the offset sanction will be applied in the affected area. If the State has still not made a complete submission by 24 months after the signing of the Notice, then the highway funding sanction will apply in the affected area. In addition, EPA must promulgate a FIP.

The sanctions will not take effect if, before 18 months after the signing of the Notice, EPA finds that the State has made a complete submittal of a plan addressing the serious area CO requirements for Las Vegas Valley. In addition, EPA will not promulgate a FIP if the State makes the required SIP submittal and EPA takes final action to approve the submittal before 24 months after the signing of the Notice. EPA encourages the responsible parties in Clark County to continue working together on the CO Plan which can eliminate the need for potential sanctions and FIP.

For additional information, please contact Larry Biland of the air Planning Office at (415) 947-4132 or biland.larry@epa.gov. Back to Las Vegas Carbon Monoxide Main Page


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