


                                       
                 UNITED STATES ENVIRONMENTAL PROTECTION AGENCY
                            REGION IX AIR DIVISION




Technical Support Document for EPA's Proposed Rulemaking on Rescission of Section 29 - Sulfur Contents of Fuel Oil, Section 30  -  Incinerators, Section 52 - Handling of Gasoline at Service Stations, Airports and Storage Tanks, and Section 60 - Evaporation and Leakage from the Nevada State Implementation Plan
                                       




                              
                            Prepared by: Kevin Gong

	October 1, 2015






RULE IDENTIFICATION

Agency

Clark County Department of Air Quality (CCDAQ)

SIP Approved Rules / Subject of this TSD

Nevada Division of Environmental Protection (NDEP) has submitted the following rule rescissions as a revision to the Clark County portion of the Nevada State Implementation Plan (SIP):

       Rule Section of the Clark County Air Quality Regulations (CCAQR)
                   Date of EPA Approval into the Nevada SIP
Section 29 (Sulfur Contents of Fuel Oil)
August 27, 1981
Section 30 (Incinerators), subsections 30.1-30.7 (excluding subsection 30.4)
August 27, 1981
Section 30 (Incinerators), subsections 30.4 and 30.8
June 18, 1982
Section 52 (Handling of Gasoline at Service Stations, Airports and Storage Tanks), subsections 52.1-52.10 (excluding subsections 52.4.2.3 and 52.7.2)
April 14, 1981
Section 52 (Handling of Gasoline at Service Stations, Airports and Storage Tanks), subsections 52.4.2.3 and 52.7.2
June 18, 1982
Section 60 (Evaporation and Leakage), (excluding sections 60.4.2 and 60.4.3)
April 14, 1981
Section 60 (Evaporation and Leakage), subsection 60.4.2
March 20, 1984
Section 60 (Evaporation and Leakage), subsection 60.4.3
June 18, 1982

Local Action
Sections 29, 30, 52, and 60 were repealed locally on April 5, 2011.

Submittal Dates
NDEP submitted the SIP revision to EPA on November 20, 2014.

Completeness Finding
This submittal was deemed complete by operation of law on May 20, 2015.


BACKGROUND

EPA first promulgated national ambient air quality standards (NAAQS) in 1971 in response to the Clean Air Act (CAA) of 1970. EPA originally established NAAQS for sulfur dioxide, total suspended particulate (TSP), photochemical oxidant, carbon monoxide (CO), and nitrogen dioxide. Over the years, EPA has revised the NAAQS and established new NAAQS. Current NAAQS exist for sulfur dioxide, particles generally less than 10 microns in diameter (PM10), particles generally less than 2.5 microns in diameter (PM2.5), ozone, CO, nitrogen dioxide, and lead.

The Clean Air Act of 1970 also established the requirement for states to submit plans, referred to as State Implementation Plans (SIPs), to provide for the implementation, maintenance, and enforcement of the NAAQS. EPA then is charged with approving, or disapproving, SIPs under section 110 of the CAA. 

The State of Nevada submitted its SIP to EPA in 1972 and has submitted many revisions to EPA over the years to address new or revised NAAQS or other changed circumstances. NDEP has air pollution control jurisdiction over all of the state of Nevada, except for stationary sources in Clark County and Washoe County. Under Nevada law, the Clark County Board of County Commissioners has jurisdiction over stationary sources in Clark County, with the exception of plants that generate electricity by using steam produced from burning of fossil fuels, which remain under NDEP jurisdiction. Clark and Washoe counties are also responsible for developing control strategy plans to address nonattainment area designations applicable to their counties. Thus, the Nevada SIP includes a set of rules and plans adopted by Clark County and Washoe County, including those adopted by Clark County that are the subject of this TSD. The current Nevada SIP is set forth at 40 CFR 52.1470.

The rules that are the subject of this TSD, Clark County Air Quality Regulations (CCAQR) sections 29 ("Sulfur Content of Fuel Oil"), 30 ("Incinerators"), 52 ("Handling of Gasoline at Service Stations, Airports, and Storage Tanks"), and 60 ("Evaporation and Leakage"), have been revised by Clark County over the years. EPA initially approved these rules in 1973 as CCAQR section 14 ("Incinerators"), section 17 ("Particulate Matter from Incinerators"), section 20 ("Gasoline Unloading from Tank Trucks and Trailers into Storage Tanks"), section 31 ("Sulfur Contents of Commercial Fuel Oil"), and section 32 ("Evaporation and Leakage"). 38 FR 12702 (May 14, 1973). Clark County then amended and renumbered the rules leading to the versions that EPA approved in the 1980s as listed above. 

Sections 29, 30, 52, and 60 established limits and control measures for emissions of oxides of sulfur (SOx), particulate matter (PM), and volatile organic compounds (VOCs) from the combustion of fuels (section 29), incinerators (section 30), gasoline dispensing facilities (section 52) and other processes and industries that use solvents, degreasing, surface coating, and cutback asphalt (section 60). VOCs (and oxides of nitrogen) are precursors to ozone formation.

Under the 1977 CAA Amendments, EPA designated all areas of the country as attainment, nonattainment, or unclassifiable with respect to the NAAQS. 
In 1978, EPA designated the Las Vegas Valley (hydrographic area No. 212) portion of Clark County as a nonattainment area for the TSP, photochemical oxidant (later 1-hour ozone), and CO NAAQS. 43 FR 8962 (March 3, 1978). Outside of Las Vegas Valley, the rest of Clark County was designated as attainment or unclassifiable for the TSP, photochemical oxidant, and carbon monoxide NAAQS. Clark County as a whole was designated attainment or unclassifiable for sulfur dioxide and nitrogen dioxide NAAQS. 

In response to the nonattainment designation of Las Vegas Valley for photochemical oxidant (later ozone), Clark County amended sections 52 and 60, which limit VOC emissions from certain types of sources, to meet the requirement for states to revise their SIPs for such areas to include provisions to require the implementation of reasonably available control technology (RACT) for VOC sources covered by EPA's control technique guidelines (CTG). See 45 FR 59334 (September 9, 1980). As listed above, at various times in the 1980s, the EPA approved these amended rules as revisions to the Clark County portion of the Nevada SIP. EPA redesignated the Las Vegas Valley to attainment for the 1-hour ozone NAAQS in 1986. 51 FR 41788 (November 19, 1986). Under the CAA Amendments of 1990, EPA designated Las Vegas Valley as a nonattainment area for the PM10 and carbon monoxide NAAQS. 

Over the years, Clark County has developed, and EPA has approved, a number of local rules to reduce fugitive dust sources (e.g., construction sites, and motor vehicle travel over paved and unpaved roads), which are the predominant sources of PM10 in Las Vegas Valley, EPA also approved Clark County's demonstration that major sources of PM10 precursors, such as sulfur dioxide and nitrogen dioxide, do not significantly contribute to violations of the PM10 standard. 69 FR 32273 (June 9, 2004). With full implementation of the fugitive dust controls, the PM10 NAAQS was attained, and in 2014, EPA approved the Las Vegas Valley PM10 maintenance plan and redesignated the valley to attainment for the PM10 NAAQS. 79 FR 60078 (October 6, 2014). Primarily due to reductions in emissions from mobile sources, the CO NAAQS was attained, and EPA approved the Las Vegas Valley CO maintenance plan and redesignated the valley to attainment for the CO NAAQS in 2010, 75 FR 59090 (September 27, 2010).

A portion of Clark County was designated nonattainment for the 1997 8-hour ozone NAAQS on June 15, 2004, and was reclassified as a marginal ozone nonattainment area on May 14, 2012 (77 FR 28424). Due to continued application of stationary source controls, including sections 52 and 60, and tighter mobile source controls, Clark County attained the 1997 8-hour ozone NAAQS, and in 2013, the EPA approved the Clark County ozone maintenance plan and redesignated the area to attainment for the 1997 8-hour ozone NAAQS. 78 FR 1149 (January 8, 2013). Clark County is currently designated as unclassifiable or attainment for all of the NAAQS.  

CCDAQ began a process to revise the CCAQR in May 2005 as the ozone redesignation process was underway. CCDAQ was concerned with regulatory conflict resulting from the delegation of authority or the local incorporation by reference of federal New Source Performance Standards (NSPS) and National Emission Standards for Hazardous Air Pollutants (NESHAPs) for many source categories covered under existing local rules.  As a result, CCDAQ repealed Sections 29, 30, 52, and 60 on April 5, 2011.


SUMMARY OF RULES

Unless otherwise specified, all other references to CCAQR Sections are to the whole section, and not specific subsections.

Section 29  -  Sulfur Contents of Fuel Oil

Section 29 limits the sulfur content in fuel oil to no more than 1 percent in order to reduce SO2 emissions. The limits are broadly written, and apply to both mobile and stationary sources. The most recently approved version was approved by EPA on August 28, 1981. 

Section 30  -  Incinerators

Section 30 establishes operating requirements and emission limits on particulate matter for incinerator units. The most recently approved version was approved by EPA in parts on August 27, 1981 and June 18, 1982. All subsections are subject to the request for rescission.

Section 52  -  Handling of Gasoline at Service Stations, Airports, and Storage Tanks

To reduce VOC emissions, Section 52 establishes gasoline handling requirements and Stage 1 vapor recovery requirements for gasoline service stations, airplane refueling areas, and other storage tank facilities with an annual throughput of at least 96,000 gallons per year. The most recently approved version was approved by EPA in parts on April 14, 1981 and June 18, 1982. All subsections are subject to the request for rescission.

Section 60  -  Evaporation and Leakage

Section 60 establishes requirements to control evaporation and leakage of VOCs. Subsections 60.2 and 60.3 describe operating conditions and limits for general degreasing operations and large appliance coating operations. Subsection 60.4 prohibits the use of cutback asphalt in the Las Vegas Valley. The most recently approved version was approved in parts by EPA on April 14, 1981, June 18, 1982, and March 20, 1984. All subsections are subject to the request for rescission.

EVALUATION CRITERIA 

The following criteria were used to evaluate the request for rescission of these control measures from the SIP.  

      1.	Stringency - CAA Section 172(c)(1) requires nonattainment areas to implement all reasonably available control measures (RACM), including such reductions in emissions from existing sources in the area as may be obtained through the adoption, at a minimum, of reasonably available control technology (RACT), as expeditiously as practicable. 
      
      2.	SIP Relaxation - CAA Section 110(l) prohibits EPA from approving any SIP revision that would interfere with any applicable requirement concerning attainment and reasonable further progress (RFP) or any other applicable requirement of the CAA. 
      
      3.	General Savings Clause - CAA Section 193 prohibits the modification of any SIP-approved control requirement in effect before November 15, 1990, in a nonattainment area unless the modification insures equivalent or greater emission reductions of such air pollutant.
      
EPA EVALUATION

A summary of our evaluation of the three criteria follows.

      1. 	Stringency.  Clark County is currently designated as attainment or unclassifiable for all of the NAAQS, and thus, RACM/RACT is not an applicable requirement within the county. Sections 52 and 60 were amended, and approved, to meet the RACT requirements under the CAA, as amended in 1977, but, given Clark County's attainment status with respect to the ozone NAAQS, RACT level controls for VOC are no longer specifically required to be retained.
      
      2. 	CAA Section 110(l).  The initial staff report provided with the November 20, 2014 SIP revision submittal did not contain enough detail to evaluate the impact of these rescissions on attainment and maintenance of the NAAQS for the purposes of CAA section 110(l). EPA requested additional information from CCDAQ and CCDAQ provided two supplemental reports in response,[,] 
      
          a.	CCAQR Section 29.  As noted above, Section 29 Sulfur Content in Fuels) establishes a fuel oil sulfur limit of 1% (which is equivalent to 10,000 ppm). Fuel oil includes both distillate (diesel) fuel and residual fuel. CCDAQ contends generally that Section 29 is no longer necessary because EPA has established lower sulfur content limits in 40 CFR 80.510 for mobile sources and in various NSPS and NESHAP regulations for applicable stationary source categories. CCDQA notes that applicable NSPS and NESHAP regulations incorporate the sulfur limits in 40 CFR 80.510. As an example, CCDAQ cites EPA's sulfur limits for fuel used by stationary compression ignition internal combustion engines (ICE) at 40 CFR 60.4207 and 40 CFR 63.6604.
          
          We agree with CCDAQ's basic contention that EPA mobile and stationary source regulations have made Section 29 largely unnecessary. The sulfur limit (15 ppm sulfur) in 40 CFR 80.510, for example, which applies to diesel fueled nonroad equipment, locomotives and marine engines, is several orders of magnitude lower than the 10,000 ppm sulfur limit in Section 29. Moreover, to the extent that the NSPS do not apply the limits in 40 CFR 80.510, they generally establish sulfur limits considerably lower than 10,000 ppm. For example, 40 CFR 60.4207(d) establishes a 1,000 ppm sulfur content limit beginning on June 1, 2012 for certain stationary compression ignition ICE.
          
          Thus, with respect to diesel fuel, the sulfur limits in Section 29 are not necessary to retain in the SIP. Residual fuels, e.g., Bunker C, are generally higher in sulfur content and could exceed 10,000 ppm. However, the trend in residual fuels, like diesel fuel, is toward lower sulfur content. CCDAQ reports that no Bunker C is in use in Clark County and there is no indication that rescission of Section 29, which has already been rescinded locally, from the SIP will have any effect on its use.
          
          Lastly, we note that ambient concentrations of sulfur dioxide in Clark County are well below the applicable NAAQS. More specifically, the 2012-2014 design values for sulfur dioxide in Clark County, as posted on EPA's design value website (www.epa.gov/airtrends/values.html), are as follows:  1 ppb, annual average (compared to 30 ppb NAAQS); 4 ppb, 24-hour average (compared to 140 ppb NAAQS); and 8 ppb (compared to 75 ppb NAAQS). Sulfur oxides are also precursors to PM2.5, but as with sulfur dioxide, PM2.5 design values in Clark County are well below the applicable NAAQS:  9.9 ug/m[3], annual average (compared to 12 ug/m[3]) and 24 ug/m[3], 24-hour average (compared to 35 ug/m[3] NAAQS). Therefore, even if there were an incremental increase in emissions of sulfur oxides in Clark County due to the rescission of Section 29, there is no realistic possibility that such an increase would interfere with attainment of the sulfur dioxide or PM2.5 NAAQS in Clark County. 
          
          b. 	CCAQR Section 30.  Local incinerators previously subject to Section 30 (Incinerators) are generally covered by more stringent Federal NSPS and NESHAP that have been delegated to CCDAQ for local enforcement. These include 40 CFR part 60, subparts Cb, Ce, E, Ea, Eb, Ec, and AAAA-FFFF. Thus, CCDAQ asserts that the requirements in Section 30 are unnecessary. EPA agrees that NSPS and NESHAPs generally impose more stringent PM limits to incinerators than Section 30. We also note that stationary sources, of which incinerators represent a small fraction, contribute little to ambient PM10 concentrations in Clark County. Elevated PM10 concentrations in Clark County are caused, rather, by fugitive dust sources (e.g., travel over unpaved roads and parking lots and wind-blown dust). Thus, any incremental increase in PM10 emissions due to rescission of Section 30 from the SIP would not interfere with attainment of the PM10 NAAQS in Clark County.
          
          c.	CCAQR Section 52.  CCDAQ asserted that Section 52 (Gas Dispensing Facilities (GDFs)) could be superseded by delegated Federal NESHAP at 40 CFR 63 subparts BBBBBB and CCCCCC for GDFs. EPA noted that the applicability thresholds in the NESHAP (1.2 million gallons per year) differed substantially from those in Section 52 (96 thousand gallons per year). In addition, Section 52 mandated the use of Stage 1 vapor recovery technologies at applicable GDFs. The repeal of Section 52 would allow GDFs operating between 96 thousand gallons per year and 1.2 million gallons per year to discontinue Stage 1 vapor recovery.
          
          	CCDAQ replied that GDFs must comply with VOC limits for New Source Review under Section 12.1 of the CCAQR and that such VOC limits were comparable to approximately 385 thousand gallons per year. The number of GDFs that were operating at a level between the Section 12.1 applicability limit and the Section 52 applicability limit was 88, and of those still operating today, the VOC emissions of these stations was 82.4 tpy, or .15% of the total VOC inventory.
          
          	EPA notes that while the current set of GDFs operating at a level between the thresholds of Sections 12.1 and 52 may be small, nothing prevents this set of GDFs from growing. EPA also notes that this analysis relies on Section 12.1 New Source Review VOC limits as an applicability threshold to trigger a permitting process for GDFs. NSR permitting, while potentially requiring similar control measures as SIP control measures, cannot be used in lieu of an equivalent SIP requirement unless CCDAQ submits these source specific permit requirements for approval into the SIP. 
          
          	Finally, CCDAQ explicitly listed Section 52 as one of several "Permanent and Enforceable Emission Reduction Control Measures" in its 2011 ozone maintenance plan for the 1997 8-hour ozone standard. CCDAQ's maintenance plan explicitly relies on control measures in Section 52 (albeit the locally enforced version, not the less stringent SIP-approved version) in order to demonstrate maintenance of the 1997 ozone NAAQS through 2022. CCDAQ has not demonstrated that removing this control measure is protective of the NAAQS, particularly since the 2012-2014 ozone design value in Clark County exceeds the 2008 ozone NAAQS (0.078 ppm, 8-hour average in Clark County compared to 0.075 ppm, 8-hour average NAAQS). 
          
          d.	CCAQR Section 60.  CCDAQ asserted that large scale degreasing operations that were previously covered under this rule were no longer present within the County. US EPA agrees with this assertion.
          
          	Additionally, CCDAQ asserted that Section 60.4's prohibition on the use of cutback asphalt during warm months is unnecessary to retain as cutback asphalt use in the maintenance area is not a significant contributor to VOC emissions. CCDAQ also pointed to several specifications on the use of cutback asphalt from the Southern Nevada Regional Transportation Commission, and to communications with major paving companies in the County, to support the assertion that cutback asphalt is not widely used. 
          
          	However, the contribution of cutback asphalt to emissions in the county is approximately .32% of the total VOC inventory. CCDAQ has not demonstrated that removing this control measure is protective of the NAAQS, particularly since the 2012-2014 ozone design value in Clark County exceeds the 2008 ozone NAAQS (0.078 ppm, 8-hour average in Clark County compared to 0.075 ppm, 8-hour average NAAQS).
          
      3. 	CAA Section 193.  The Las Vegas Valley was reclassified to attainment for the 1-hour ozone standard in 1986 and was also designated attainment or unclassifiable for the other NAAQS. As a result, CAA Section 193 is not applicable.

EPA ACTION 

For reasons discussed above, EPA staff recommends that the rescission of Clark County Air Quality Regulations Sections 29, all subsections; and 30, all subsections; from the Nevada SIP be approved. 

For reasons discussed above, EPA staff recommends that the rescission of Clark County Air Quality Regulations Sections 52, all subsections, and 60, all subsections, from the Nevada SIP be disapproved.

REFERENCES 

 Letter dated November 20, 2014, from Colleen Cripps, Ph.D., Administrator, Nevada Division of Environmental Protection, to Jared Blumenfeld, Regional Administrator, US EPA Region 9, with enclosures including "Proposed Revision to Clark County Part of Nevada State Implementation Plan: Revisions to Clark County Air Quality Regulations Sections 26 and 92, and Repeal of Sections 11, 29, 30, 52, and 60," and other SIP submittal documents.
 "Rule Analysis: Comparison of Stringency of Repealed Clark County Sections 30 and 60 with Current Requirements," Clark County Department of Air Quality, May 2015.
 "Analysis of Remaining EPA Issues Pertaining to the Repeal of Clark County Air Quality Regulations Sections 29, 52, and 60," Clark County Department of Air Quality, August 14, 2015.
 "8-Hour Ozone Early Progress Plan for Clark County, Nevada," Clark County Department of Air Quality and Environmental Management, June 2008.
 "Ozone Redesignation Request and Maintenance Plan, Clark County, Nevada," Clark County Department of Air Quality and Environmental Management, March 2011.
 "Redesignation Request and Maintenance Plan for Particulate Matter (PM10), Clark County, Nevada," August 2012.
