Technical Support Document for EPA's IVotice ofProposed Rulemaking

on Revisions to the California State Implementation Plan

as submitted by the State of California, for the Imperial County Air Pollution Control District

EPA's Analysis of Imperial County Air Pollution Control District's Regulation VIII - Fugitive Dust Rules 800-806

United States Environmental Protection Agency, Region IX Air Division

February 20 10I. Overview ofRegulation VIII and EPA's Imperial County 

### PMlo Actions

A. Regulation VIII Adoption and Submittal Chronology



# I 1 Board adopted revised (Rule 800) and new (Rules 801-806) versions of 

# 1 Date


# 1 the Regulation VIII fugitive dust rules. The California Air Resources Board (ARB) submittedtheNovember 8, 

## 1 2005 version of Regulation VIII to EPA as a revision to the California 

### 1 Action

Plan 

### SIP).^ July 21,2006 EPA found ARB'SJune 16, 2006 submittal of Regulation VIII complete.2 November 8, 2005 

### ) The Imperial County Air Pollution Control District (ICAPCD) Governing

EPA has not incorporated into the SIPprevious versions of any ofthe Regulation VIII rules.



### B. Regulation VIII Summary

ICAPCD's Regulation VIII consists of seven interrelated rules designed to limit emissions of inhalable coarse particulate matter (PMlo) from anthropogenic fugitive dust sources in Imperial County.

Rule 800. General Requirements for Control ofFine Particulate Matter, provides definitions, a compliance schedule, exemptions and otherrequirements generally applicable to all seven rules. It also describes specific exemptions and requirements for the U.S. Department of Defense (DOD), U.S. Bureau ofLand Management (BLM) and 

### U.S. Border Patrol (BP). Appendices A and B describe methods for determining compliance with opacity and surface stabilization requirements in Rules 801 through 805.

Rule 801, Construction and Earthmoving Activities, establishes a 20% opacity limit and control requirements for construction and earthmoving activities. Affected sources must submit a dust control plan and comply with other portions of Regulation VIII regarding bulk materials, carryout and track-out, and paved and unpaved roads. The rule exempts single family homes and waives the 20% opacity limit in winds over 25 mph under certain conditions.
Rule 802, Bulk Materials, establishes a 20% opacity limit and control requirements for bulk material handling, storage, transport and hauling.

Rule 803, Carry-Out and Track-Out, establishescontrol requirements for removing carry-out and track-out material transported onto paved roads from unpaved roads and areas.

1 Letter from Michael Scheible, ARB, to Wayne Nastri, EPA,June 16,2006. 2 Letter from Deborah Jordan, EPA, to Catherine Witherspoon, ARB, July 2 1,2006.
Imperial CountyAPCD -Regulation VIII 

### - 2 - TSD, 02110Rule 804, Open Areas, establishes a 20% opacity limit and requires land owners to prevent vehicular trespass and stabilize disturbed soil on certain open areas. Agricultural operations are exempt from the rule.

Rule 805, Paved and Unpaved Roads, establishes a 20% opacity limit and control requirements for unpaved haul and access roads, canal roads, and traffic areas that meet certain size or traffic thresholds. Single family residences and agricultural operations are exempt from the rule.

Rule 806. Conservation Management Practices, requires agricultural operation sites greater than 40 acresto implement at least one conservation management practice (CMP) for each ofthese categories: land preparation and cultivation, harvest activities, unpaved roads and unpaved traffic

areas.

C. 

### PMloBackground and Related EPA Actions Concerning PMloand Imperial County

PMlo contributes to effects that are harmful to human health and the environment, including premature mortality, aggravation ofrespiratory and cardiovascular disease, decreased lung function, visibility impairment, and damageto vegetation and ecosystems. The population in Imperial County may be particularly vulnerable to these health impacts, having a high percentage of low income (19.7% of families below the poverty level, versus 9.6% nationally) and minority populations (76.0% Hispanic or Latino, versus 15.1 % nationally), a low educational attainment rate (63.0% high school graduates or higher, versus 84.5%nationa~l~),~ and decreased access to health care (including West Imperial and Calexico Medically Underserved Areas and Health Professional ShortageAreas throughout ~m~erial),~ all ofwhich may impact a community's ability to avoid and/or cope with environmental impacts. The Clean Air Act (CAA) requires Statesto submit regulations that control PMlo emissionsto protect health ofboth the general and sensitive populations.
Upon enactment ofthe 1990Clean Air Act (CAA) Amendments, Imperial County was classified

as moderate nonattainment for the PMlo national ambient air quality standards (NAAQS) under CAA Sections 107(d)(4)(B) and 1 88(a). By November 15, 1991, such areas were required to develop and submit SIP revisions providing for, among other things, implementation of reasonably available control measures (RACM). CAA Sections 188(a)and (c)(l)also required moderate PMlononattainment areas to attain the PMlostandardsby December 3 1, 1994.

OnAugust 11, 2004, EPA reclassified Imperial County as serious nonattainment for PMlo.As a result, under CAA Section 189(b)(l)(B),all best available control measures (BACM) were required to be implemented inthe area within four years ofthe effective date ofthe

3 U.S. Census Bureau, factfinder.census.gov, http:/ifactfinder.census.gov/servletiACSSAFFFacts'? event=Search&geo id=& geoContext=& street=& county-i rnpcrial+countv& citvTown-imperial+county& state-04000US06& zip-& lang=en& sse=on&pctxt-fph&p~sl-0 L0; - 4 U.S. Department ofHealth and Human Services, muafind.hrsa.gov
Imperial County APCD -Regulation VIII -3-
TSD, 02/10reclassification, i.e., by September 10,2008. Under Section 188(c), serious PMlo nonattainment

areas were required to attain the PMlo standard by December 31, 2001 unless granted an extensionunder Section 1 88(e).5

On December 11,2007,EPA determined that Imperial County had not attained the 24-hour PMlo standard by December 31,2001. The State was required to submit by December 1I,2008, a SIP revision including RACM and BACM. Pursuant to CAA Section 189(d),the plan was also required to provide for expeditious attainment and an annual reduction in PMlo emissions of not less than 5% of the most recent inventory until attainment.6

On August 11, 2009, ICAPCD's Board adopted the "2009 Imperial County State Implementation Plan for Particulate Matter Less Than 10Microns in Aerodynamic Diameter, Final," August 

### I 1, 2009 (2009 PMloSIP). The 2009 PMloSIP has not been submitted to EPA by the State.

11. EPA's Evaluation ofRegulation VIII

A. Evaluation Criteria

EPA is primarily evaluating Regulation VIII against three criteria:
Enforceability 

### - Regulations must be clear regarding, for example, who must comply, by what date, the standard of compliance,the methods used to determine compliance, and the process and criteria for obtaining any variation from the normal mode of compliance.7Guidance used to help evaluate enforceability includesthe Bluebook and the Little ~luebook.~

SIP Relaxation -CAA Section 1lO(1) statesthat EPA cannot approve SIP revisions that interfere with attainment ofthe NAAQS or any other applicable requirement ofthe Act.

BACM

-We have defined BACM to be, among other things, the maximum degree of emission reduction achievable from a source category which is determined on a case-by-case basis considering energy, economic, environmental impacts and other costs.9 We have outlined in our guidance a four step process for identifLingBACM: (1) develop a detailed emissions inventory

5 69FR 48792 (August 11,2004). 6 72 FR 70222 (December 11,2007). 7 "Review of State Implementations Plans and Revisions for Enforceability and Legal Sufficiency" (Enforceability Guidance), Craig Potter, EPA, September23, 1987. See also General Preamble for the Implementation of Title I of the Clean Air Act Amendments of 1990. 57 FR 13498, 13502 and 13541 (April 16, 1992) (General Preamble) and CAA 

### $5l lO(a)(2) and 172(c)(6). littp:i!www.epa.~ovicom~liance~resources!policies:!civiIlcadstationarvi'review-enfrpt.pdi.. 8 "Guidance Document for Correcting Common VOC and Other Rule Deficiencies," U.S. EPA Region IX, August 2 1,200 1(the Little Bluebook), and "Issues Relating to VOC Regulation Cutpoints, Deficiencies, and Deviations," U.S. EPA, OAQPS, May 25, 1998 (The Bluebook). 9 "State Implementation Plans for Serious PM-I0Nonattainment Areas, and Attainment Date Waivers for PM-I0 Nonattainment Areas Generally; Addendum to the General Preamble for the Implementation of Title I ofthe Clean Air Act Amendments of 1990," 59 FR 4 1998,42010 (August 16, 1994) (Addendum).
Imperial CountyAPCD -Regulation VIll -4-
TSD, 02/10of PMlo sources: (2) evaluate the impact of various sources on PMlo concentrations to determine which are significant: (3)identify potential BACM for significant source categories and evaluate their reasonableness considering technological feasibility, costs, energy and environmental impacts; and (4)provide for the implementation of BACM or provide a reasoned justification for rejecting any potential BACM. lo

When a moderate area isreclassified to serious, the requirement to implement RACM in CAA Section 189(a)(l)(C)remains. However, EPA does not ordinarily conduct a separate evaluation to determine whether measures for significant sources in a serious area also meet the RACM requirements. This is because in our serious area guidance, we interpret the BACM requirement

as generally subsuming the RACM requirement (i.e., if we determine that the measures are indeed the "best available," we have necessarily concluded that they are "reasonably available").

# '

B. Evaluation of Imperial County 

### PM Inventory for Sources Requiring BACM

CAA Section 189(b)(l)(B)and EPA guidance require that seriousPMlo nonattainment areas implement BACM for all significant source categories. A source category is presumed to contribute significantly to a violation ofthe PMloNAAQS if its PMlo impact exceeds 5 pg/m3.12 In October 2005, ICAPCD produced an analysis of BACM to support adoption of Regulation VIII. It applied the 5 pg/m3threshold to the available PMlo inventory and 2002-2004 ambient PMlo data, and determined a de minimis level for significant source categories as 4.9 tons per day of ~~10.'~ ICAPCD identified four activitiesexceeding this level that were thus defined as significant sources needing BACM:

1. Windblown dust from open non-crop-farm areas; 2. Entrained and windblown dust from unpaved roads; 3. Windblown dust from non-pasture agricultural lands; and 4. Tilling dust.I"

In 2008 and 2009, to support its PMlo attainment plan, ICAPCD revised its analysis of significant

sources ofPMlo to reflect 2006-2008 ambient PMlo data and a 2005 base year inventory.15 The State sought to exclude exceedances caused by high winds for regulatory purposes under EPA's exceptional events rule.'' All remaining PMlo exceedances occurred during low winds, so

1059 FR 42010-42014. 11 59 FR 42010,42013-42014. Seealso 57 FR 13498, 13540-13541. 12 59 FR42011. 13 "Draft Final Technical Memorandum: Regulation VIII BACM Analysis," October 2005 (2005 BACM Analyis), Pg 8. 14 2005 BACM Analysis, Table 3-6, pg. 16. 15 2009 PMlo SIP, section 3.2. 16 40 CFR 50.la) and 50.14. See letter from James N. Goldstene, ARB, to Deborah Jordan, EPA, May 19,2009, requesting exclusion of September 2,2006,April 12,2007,and June 5,2007 Imperial County PM,oexceedances.

Imperial County APCD -Regulation VIII TSD, 02/10ICAPCD adjusted the inventory to eliminate windblown dust" and better reflect emissions from Mexico and other factors, and calculated a new de minimis threshold of 2

-2.9% ofthe dayspecific exceedances. ICAPCD identified onlytwo activities exceeding this level that were defined as significant sourcesneeding BACM:

1. Entrained dust from unpaved roads; and 2. Tilling dust from agricultural operations.I8

On December 22,2009, we did not concur with the State's exceptional event requests for high winds in 2006 and 2007.19As a result, we replicate Imperial's de minimis calculations below without excluding the high wind events. The following table lists the measured ambient PMlo concentrations during exceedances caused largely by local (i.e., not Mexican) sources. Depending on the specificmonitor, 

### 2-3% ofImperial County's annual inventory is calculated to result in a 5 pg/m3contributionto the air quality exceedances.

-- ' 

### Exceedance (Date, Monitor, Value)

# *' ' 

### Percent Equaling 5 

### ug/m3

# I

,- 

### --

The following table lists anthropogenic source categories that meet or exceed thisthreshold and

are therefore considered significant sourcesneeding BACM. 6/05/07,Niland, 162tLg/m3 6/05/07, Westmorland, 226 yg/m3 

# I Emission Source


# , Category From ICAPCD Average Annual 

### PMlo Inventory ~missions~' %ofTotal 5 + 162pg/m3= 3% 5 + 266 pg/m3=2%



### 1 Open areas I 

## 1 Windblown Dust, Other ~~Pt~d, 60% 

# 1 (npaved roads

172009 PMlo SIP, Table 3.6, pg. 3-8. 182009 PMloSIP, Table 3.7, pg. 3-9. 19 Letter, with enclosure, from Laura Yoshii, EPA to James Goldstene, ARB, Re: exceptional events requests regarding exceedances of the PM-I0 NAAQS in Imperial County, CA, December 22,2009. 20 Data for this column are from the 2009 PMloSIP, Table 2.1, pg. 2-4. 21 Emissions data are from the 2009 PMloSIP, Table 3.3, pg. 3-4.

Imperial County APCD -Regulation VIII TSD, 02/10r~ntrained Unpaved Road Dust, CityICounty 

# 1 25 tpd, 9% Entrained Unpaved Road Dust, Canal Windblown Dust, Unpaved CityICounty Road 8tpd, 3% Windblown Dust, Unpaved Canal Road Windblown Dust, Unpaved Farm Road Agricultural lands Tilling 

### 7tpd, 2% Windblown Dust, Non-Pasture Agricultural Lands 11tpd, 4%

C. Summary ofEPA Evaluation Criteria
Enforceability - The recordkeeping, reporting and other rule provisions help ensurethat Regulation VIII, for the most part, canbe enforced. However, we have identified below several provisions in Regulation VIII that we believe do not meet the enforceability requirements of CAA Section 1 1 O(a).

SIP Relaxation - There isno prior version of Regulation VIII in the SIP, so our action does not raise issues regarding SIP relaxation and CAA Section 1lO(1).

BACM -We have compared Regulation VIII with analogous requirements in the South Coast Air Quality Management District (SCAQMD), San Joaquin Valley Air Pollution Control District (SJVAPCD), Maricopa County Air Quality Department (MCAQD), Clark County Department of Air Quality and Environmental Management (CCDAQEM) and other areas. In doing so,we recognize that some variability exists among sources in different areas, and that technically and economically feasible controls in one area may not be feasible in another area. Based on our analysis, we believe that Regulation VIII is generally consistent with analogousrequirements in other serious PMloareas and includes many provisions consistent with CAA requirements for BACM and with established EPA policy and guidance. However, we identie several provisions below where the State has not adequately demonstrated BACM implementation.

D. Rule Deficiencies

The following deficiencies preclude EPA's full approval ofRegulation VIII. Section 1I.D.1below identifies deficiencies related to sources for which BACM is required as discussed above in Section 1I.B.While, as indicated above, BACM is determined on a case-by-case basis, the identification ofpotential BACM for a significant source category in Imperial County necessarily involves a consideration of control measures adopted andlor implemented in other geographical areas for the same and similar source categories. Therefore, in the following discussions we reference rules, statutes and other requirements in such areasthat inform the determination of BACM for Imperial County sources.

Section II.D.2 identifies one deficiency related to bulk materials, a source category for which BACM is not currently required based on the information availableto EPA to date.

Imperial County APCD - RegulationVlII TSD, 02/101. BACM-Related Deficiencies
Open Areas
a. Recreational off-highway vehicle (oHv)~~ activity causes much ofthe PMlo emissions from open areas in Imperial County. Rule 804 regulates only a smallportion ofthese emissions, including some emissions from OHV activity on State lands where Rule 804 is apparently not being implemented. The vast majority ofthe OHV emissions in Imperial County are addressed only by requirements in Rule 800 Section F.5 for dust control plans (DCPs) for sources under the control ofBLM. While BLM isrequired to describe in the DCPs the dust control measures that it intendsto implement, BLM is not required to implement any specific BACM-level controls for OHV use.

ICAPCD must provide an analysis ofpotential BACM controls for OHV activity in open areas and on unpaved roads and paths that are exempt from the specific requirements and measures in Rules 804 and 805 and identify, adopt and submit any appropriate revisions to Rules 800, 804 and 805. Such analysis should address as its starting point measures in EPA's 1992RACM guidance at 57 FR 18070, 18072 (April 28, 1992) and analogousrequirements in other areas such as Arizona Revised Statute $49-457.03,and Clark County Air Quality Regulations, Section 90. ICAPCD should evaluate the feasibility and impacts ofadditional restrictions in recreational OHV areas, such as closing some of the 250 square miles that are open to OHV use that are particularly likelyto impact populations, and restricting OHV activity during summer months when there is virtually no rain to reform surface crusts. In addition, ICAPCD must implement Rules 804 and 805 on all State lands used by OHVs or demonstrate in its BACM analysis that an exemption for OHV activity on such lands is appropriate. See Section 1II.B.1below for further discussion.

b. The term "disturbed surface area" is used in several Regulation VIII rules but is never defined. For example, Rule 804 appliesto a source category for which BACM is required and relies on the undefined term to describe rule applicability in Rule 804 Section B. In order to ensure that these rules are enforceable at a BACM level, ICAPCD must define "disturbed surface area" as do, for example, SJVAPCD Rule 8010 and SCAQMD Rule 403.
Unpaved Roads and Traffic Areas

c. Rule 805 Section D.2 exempts agricultural roads and traffic areas from opacity and stabilizationrequirements applicableto non-agricultural operation sites. Farm roads and traffic areas are only required to implement a CMP from the menus for unpaved roads and traffic areas in Rule 806. In contrast, for example, SJVAPCDrequires that CMPsbe implemented to meet opacity and surface stabilization requirements at the following

22 As used in this Technical Support Document, the term "off-highway vehicle" or OHV includes all vehicles subject to the exemption in Rule 800 Section E.6 for recreational use ofpublic lands in Imperial County.
Imperial County APCD - Regulation Vlll - 8 

### - TSD. 02/10thresholds: unpaved farm roads with 

### 2 75 VDT or

## >25 average daily vehicle trips by three or
more axle vehicles; unpaved traffic areas with 2 50 average daily vehicle trips (on an annual basis) or

## >25 average daily vehicle trips (on an annual basis) by three or more axle vehicles. ICAPCD must remove the exemption in Rule 805 Section D.2 or demonstrate how BACM is met in Imperial County for farm roads and traffic areas that are subject to less stringent requirements than other roads and traffic areas in the County and farm roads and traffic areas in other areas.

d. Rule 800 SectionF.6.c exempts roads owned or operated by BP from Rule 805requirements that are "inconsistent with BP authority and/or mission." It is not clear what this exemption is intended to address, or how it would be implemented and enforced,particularly because both BP and ICAPCD staffhave informally informed EPA that BP does not own or operate any roads in Imperial County. ICAPCD must either remove this exemption or narrow the exemption to specific mission activities and demonstrate that the exemption is minimized and necessary consistent with BACM requirements.

e. The CAA requires ICAPCD to implement BACM by 2008 (i.e., four years after reclassification to serious).23 Rule 805 SectionE.7 allows the County until 20 15 to stabilize heavily-travelled unpaved non-farm roads. This schedule is inconsistent with the statutory requirement and ICAPCD has not provided adequate evidence that this schedule is as expeditious aspracticable, based upon economic feasibility or any other appropriate consideration. In evaluating economic feasibility of a measure that depends on public funding, EPA considerspast funding of similar activities and availability of funding sources to determine whether public agencies have made good faith effortsto expeditiously implement the available control measures. ICAPCD must expedite the schedule for implementation ofthis measure or demonstrate good faith efforts to increase funding and priority of road stabilizationprojects consistent with national guidance. See SectionIII.B.3 below for further discussion.

f. Rule 805 Section E.7's requirement to stabilize all non-exempt unpaved County roads is also not adequately enforceable as currently structured. If ICAPCD retains the same structure, it must revise Rule 805 Section E.7 to clarify that the County must: (a) implement (and not just submit) a stabilizationplan; (b) stabilize different unpaved roads each year; and (c) maintain all stabilized roads.
Agriculture (see also section 1I.D.I.c above)
g. Rule 806 Section E lists CMPs intended to control emissions from agricultural land preparation and cultivation (which includes tilling), harvest activities, unpaved roads and traffic areas, but these CMPs are broadly defined and there is no other mechanism in the rule

23 Since2008 has passed, BACM is now required to be implemented as expeditiously as practicable. Delaney v. EPA, 898 F.2d 687 (9th Cir. 1990).
Imperial County APCD -Regulation Vlll TSD, 02/10to ensure specificity. 24 The absence of sufficiently defined requirements makes it difficult for regulated parties to understand and comply with the requirements, and makes it difficult for ICAPCD or others to verify compliance and to enforce the requirements if necessary. The lack of specificity similarly renders it difficult to assess whether the measures constitute BACM level controls. ICAPCD must revise Rule 806to ensurethat CMPs are enforceable and are implemented at a BACM level or demonstrate why such a rule revision is not necessary. 25 SJVAPCD Rule 4550, for example, relies on an application submittal and approval process to ensure sufficient specificity ofthe particular measures implemented at each source. Great Basin Unified Air Pollution Control District (GBUAPCD) Rule 502 also has an application submittal and approval process. Alternatively, there may be another mechanism to ensure adequate specificity such asby revising and clarifying ICAPCD's CMP application forms.

h. Rule 806 Section 

### E requires one CMP from the "land preparation and cultivation" category and one CMP from the "harvest" category, while SJVAPCD Rule 4550 requires an additional CMPfrom the "cropland-other" category. GBUAPCD Rule 502 also requires that one CMP eachbe selected from the "land preparation and cultivation," "harvest," and the "croplandother" categories. ICAPCDmust similarly require an additional CMP for cropland, or demonstrate why that is not appropriate.

i. Windblown dust from non-pasture agricultural lands is also a significant source of PMlo that requires BACM independent of agricultural tilling. The CMPs in Rule 806 Section 

### E, however, mainly control emissions by reducing the number of vehicle passes across fields, and sources are not required to select BACM level practices for controlling windblown dust from active or fallow agricultural fields. ICAPCD must revise Rule 806to require BACM level windblown dust controls. In general, EPAbelieves that the evaluation of BACM level

24 For instance, one of the CMPsthat is both in the land preparation and cultivation menu in Section E.l and the harvest menu in Section E.2 is "equipment changes/technological improvements" which is defined in Section C.15

as "To modify the equipment such as tilling; increase equipment size; modify land planning and land leveling; match the equipment to row spacing; grantingto new varieties or other technological improvements. It reduces the number ofpasses during an operation, thereby reducing soil disturbance." This definition is too broad to ensure enforceability. Moreover, because there is no mechanism to narrow the definition for a particular agricultural operation, a CMP may be implemented in a manner less stringent than a BACM level of control. In a similarly broad fashion, Section C.34 defines "speed limits," a CMP that is both in the unpaved roads menu in Section E.3 and the unpaved traffic areas menu in Section E.4, as "enforcement of speeds that reduce visible dust emissions. The dust emissions from unpaved roads are a function of speed, meaning reducing speed reduces dust." However, an appropriate speed limit or range of speed limits is not specified or otherwise ensured. 25 Section 1I.Bidentifies tilling and unpaved farm roads as significant source categories for which BACM is required. These sources are addressed by the CMP menus in Rule 806 Sections E.1 (land preparation and cultivation) and E.3 (unpaved roads). The CMPs in Rule 806 Sections E.2 (harvesting) and E.4 (unpaved traffic area) must also be fully enforceable at a BACM level because the activities occur at the same facilities and are integrally related to other activities identified as significant (i.e.,tilling and unpaved roads respectively). By analogy, where enforceable VOC reasonably available control technology (RACT) level controls are required for refineries, SIPrules generally impose leak detection and repair requirements on valves, flanges, threaded connections, and other related equipment even ifemissions from any one of these taken individually might be much smaller than the major source threshold requiring RACT.
Imperial County APCD - Regulation Vlll - 10-
TSD, 02/10controls for a particular source or activity should include consideration ofU.S. Department of Agriculture (USDA) approved conservation systems and activities. Although these guidelines may not specifically be designed to minimize air pollution, they are intended to be feasible and effective techniques that will reduce windblown dust, and thus would be appropriate

measures to consider for BACM for such sources or activities for PMlo. SCAQMD Rule 403 provides an example of such controls. See Section III.B.4 below for further discussion.

2. Non-BACM Deficiency

Rule 802 Section D. 1 allowsthe Air Pollution Control Officer (APCO) to set aside controlsthat might be used instead of water to stabilize surfaces ofbulk materials. This discretion allows ICAPCD to approve alternatives to the applicable SIP without following the SIPrevision process described in CAA Section 1 10. Moreover, ICAPCD has not demonstrated why such discretion is needed for measures such as covering, enclosing or sheltering material piles. While we prefer removal ofthe exemption and APCO discretion, SJVAPCD Rule 803

### 1 remedies the enforceability issue by requiring EPA approval.26

111. Additional Information

A. Additional Recommendations forthe Next Revision of Regulation VIII

The followingrevisions are not currently the basis for rule disapproval, but are recommended for the next time the rules are amended.

1. Rule 800 Sections C.36 and E.7 provide a broad exemption for DOD "tactical training" that may be difficult to enforce. We could not find a similar exemption in analogous SCAQMD and SJVAPCD rules and believe this exemption should be further defined and limited in Rule 800.

2. If Rule 800 SectionF.5.e. remains after addressing the deficiency summarized in section 1I.D.1 .a above, we note that the term "off-road event and/or competitions" is undefined, making it unclear asto when dust control plan and recreation area management plan (RAMP) requirements must be implemented by BLM. The 2005 BACM Analysis statesthat 5-10 events occur per year, suggesting uncertainty about the threshold and magnitude ofthese events." Depending on the response tothe issues we raise in section 1I.D.

### 1.a, it may be appropriate for the rule to identi@regular annual events and incorporate a visitor count threshold.

3. We recommend that ICAPCD add a 0% opacity atthe fenceline standard to Rules 801, 802, 804 and 805, in addition to the 20% opacity standard. SCAQMD, MCAQD, and

26 See Little Bluebook, pg. 17. 27 2005 BACM Analysis, pg. 19.

Imperial CountyAPCD -Regulat~on VllI TSD, 02/10CCDAQEM employ some version of this standard to aid enforcement.

4. Rule 802 Section D.4 exemptstransport and hauling ofbulk material within a worksite from the requirement to cover loads and clean haul beds. We recommend that ICAPCD remove these exemptions. SJVAPCD Rule 8031,for example,requires onsite haul trucks to cover loads.
5. Regardless ofvehicle size and number oftrips, Rule 803 Section D.2 waives all carry-out and track-out control requirements for operationsthat remain at a location no more than 10days in a 90 day period. In theory, this could waive these basic controls for operations with thousands oftruck trips. We recommend that ICAPCD revise this consistent with SJVAPCD Rule 8041, for example, which uses only vehicle trips per day to determine applicability.

6. ICACPD should consider revising Rule 804 Section B to apply requirements to smaller sources. MCAQD Rule 310.01,for example, applies similar requirements to 0.1 acres with 500 square feet (sq. ft.) ofdisturbed surface area compared to Rule 804's 0.5 acres in urban

areas and 3.0 acres in rural areas with 1000 sq. ft. of disturbed surface area.

7. ICAPCD should consider revising Rule 805 requirements for unpaved traffic areas in light of more stringent requirements in other areas, such as MCAQD Rule 310.01. Specifically, Rule 805 Section E.5 exempts areas smallerthan one acre and 75 ADT from control while Rule 310.01only exempts lots serving four or fewer residential units. Rule 310.01also establishes track-out clean-up requirements, while Rule 805 doesnot.

8. ICAPCDprojects that the 199miles of County roads exceeding Rule 805's 50 ADT threshold will be stabilized using gravel, a control measure estimated to be 60% effective. For the most highly traveled roads, we recommend that ICAPCD consider requiring paving, which is estimated tobe 99% effective in reducing entrained dust emissions and provides a longer lasting stabilized surface preventing windblown emissions. See Section III.B.2 below.

9. ICAPCD estimates that canal roads contribute the most unpaved road mileage and PMlo emissions,but projects that no canal roads meet Rule 805's applicability threshold and are subjectto control requirements. To address this large source of emissions, ICAPCD could consider a lower trip threshold in Rule 805 Section E.4. See Section III.B.2 below. We also recommend that ICAPCD consider strengthening the clarity and enforceability of canal bank control options described in Rule 805 Section F.2. For example, "canal bank surface maintenance" is vague and may be difficult to enforce.

10. We recommend further refinements to the unpaved road inventory. Specifically, ICAPCD's ADT and VMT estimates may come partly from a 1993 SIP.28 However, the ICAPCD documentation does not describe how these estimates were derived, whether they were based

28 2005 BACM Analysis, Appendix B.
[rnperial County APCD -Regulation VIll TSD, 02/10ontraffic counts, or whether they remain valid many years later. See SectionIII.B.2 below.

1 1.Rule 806 Section C.7 defines "Chemigation/Fertigation," while Section

### E.1andthe CMP Plan refer to "Chemical/Fertigationmand "Chemical Fertigation," respectively. We recommend using consistent names to enhance rule clarity.

12. Rule 806 Section D. 1 exempts agricultural sourcesthat are below 40 acres. While SJVAPCD Rule 4550 exempts farms below I00 acres, Maricopa's BMP rule29 and SCAQMDRule 403 exempt farms below 10 acres. The 2009 PMlo SIP notesthat "According to information obtained from USDA/NRCS, parcels of size 340 acres account for approximately 96.95% of the area of all agricultural parcels in Imperial County. Thus, if emissions per acre of agricultural parcel are equal for all parcels (regardless of size), then Rule 806 applies to 

## - 97% oftotal emissions from all agricultural parcels."30We question the assumptionthat emissionsper acre ofagricultural parcel are equal for all parcels in light of variability in crops, management practices, soil type, and other factors. As a result, we recommend ICAPCD consider lowering the exemption in Rule 806 from 40 acresto 10 acres.

13.Rule 806 Section E.3 includes CMPs that are not designed to stabilize unpaved farm roads and therefore only minimally control windblown dust (i.e., restricted access, speed limit, track-out control and wind barriers). Particularly since ICAPCD estimates 6.01 tpd of windblown emissions and only 1.35tpd ofentrained emissions from unpaved farm roads, we recommend that ICAPCDrevise this section to allow only CMPs that stabilize unpaved roads (i.e., dust suppressants, gravel, paving and watering). See Section III.B.2 below.
B. Additional Background on Selected Deficiencies and Recommendations
This section provides additional information regarding some ofthe issues identified above.

1. Emissions from 

### OHVActivity

ICAPCD estimates that windblown dust from dunes, grassland and other open areas account for 60% of annual PMlo emissions,3' and estimates that up to 22 tpd 32 of windblown PMlo from these areas are emitted from over 250 square miles (164,000 acres)33 used by recreational 

### OHV.~~ ICAPCD projects an additional 1.34 tpd ofemissions from non-wind emissions partly from OHV

29 Arizona Administrative Code Section R18-2-611, "Agricultural PM lo General Permit; Maricopa PMlo Nonattainment Area and Maricopa County Portion of Area A," 30 2009 PMloSIP, pg. 4-8. 31 See last table in Section 1I.Babove. 32 2009 PMlo SIP, Table III.B.4, Appendix III.B, pg 1II.B-8;22 tpd = 7.77+ 1.43+ 0.8 + I 1.0+ 1.I. 33 2009 PMIo SIP, Table III.B.4, Appendix III.B, pg 1II.B-8. 34 OHV activity indirectly increases PMlo emissions by disturbing vegetation and surface crusts, leaving the surface less stable and more vulnerable to emissions during subsequent winds.
Imperial County APCD - Regulation VIlI - 13 - TSD. 02/10activity onBLM and U.S. Forest Service roads.35 Additional emissions from OHVs directly entraining dust in open areas (i.e., not on established roadslpaths) are not addressed in existing emission inventories for Imperial County.

In 1992, EPA identified OHV limitations as a required RACM for moderate PMloareas under CAA Section 189(a)(l)(C),and listed three example controls: confining operationsto specific areas, requiring use permits, and banning OHV activity ICAPCD Rule 804 Section E.l requires all persons (defined at Rule 800 Section C.29to include both public and private entities) who own or otherwise havejurisdiction over open areas to restrict OHV activity in Imperial County by requiring them to maintain a stabilized surface and to meet a 20% opacity limit. Rule 805may also control some emissions from OHVs onunpaved roads. The 20% opacity limit in Rules 804 and 805 and the stabilization standards and methods found in Rule 800 Appendices A and B are common PMlocontrols and are generally consistent with other serious PMlo area fugitive dust rules. However, ICAPCD estimates that Rule 804 addresses only 1% of emissions from Imperial County's open land.37

Most emissions from OHV activity in Imperial County occur on BLM lands that are exempted from Rule 804 and Rule 805requirements by Rule 800 Section E.6. ICAPCD Rule 800 also requires BLM to submit and implement DCPs to limit PMlo from OHVs, although there are no requirements that they contain specific BACM for OHV activity. OHV activity also occurs in Ocotillo Wells State eventhough State lands are not exempted from Rule 804's opacity and stabilizationrequirements.

BLM, DOD, U.S.Fish and Wildlife, Bureau of Reclamation, and Californiaprohibit or limit, independent of Rule 804, OHV activity on substantial open areas under their control in Imperial StatelFederal agencies also charge a nominal fee for OHV areas, such as $50/year for

an OHV day use annual pass.40 While these OHV restrictions include some features ofthe 1992 RACM guidance, the State has not demonstrated that current RACM, much less BACM, is implemented for these sources. For example:

a. None ofthe OHV restrictions on BLM lands (either through the DCPs orthe restrictions to specific areas) are in regulatory form and submitted for inclusion inthe SIP pursuant to CAA Sections 

### 110and 189.

b. Despite the fees and other programs that may reduce OHV activity and hence PMlo

35 2009 PMlo SIP, Table 111.2,Appendix III.A, pg. 1II.A-6. This accounts for direct PM,, emissions caused by OHV activity by entraining dust through contact between tires and unpaved surfaces. 36 57 FR 18072, Appendix Cl (April 28, 1992). 37 BACM Amendments to Regulation VIII, Fugitive Dust Rules, ICAPCD Staff Report, November 8, 2005, Table 3, pg 6. 38 2009 PMlo SIP, Table I11.B-I,Appendix III.B, pg 1lI.B-2 39 2009 PMlo SIP, Table 1II.B-1,Appendix III.B, pg 1II.B-2. 40 California State Parks, Off-Highway Motor Vehicle Recreation Passes and Fees Schedule, 2009, http://ohv.parks.ca.gov/?page-id=25760
lmperial County APCD -Regulation Vlll TSD, 02/10emissions, there are still over 1.4million users per year to the dunes area alone,41 and over 250 square miles open to OHVs in Imperial County. No evidence was presented to suggest that fees and OHV restrictions on public land in Imperial County have been designed for and/or are effective in reducing PMloemissions and impacts.

c. ICAPCD has not provided an analysis of potential BACM controls for OHV activity. Previous ICAPCD BACM analysis for Regulation VIII in general relied largely on comparisonto SJVAPCD 's analogous Regulation VIII.~~ However, SJVAPCD does not have large OHV open areas such as those in Imperial In addition, other areas currently regulate this specific source category. SeeArizona Revised Statute 549-457.03 which prohibits recreational OHVs on PMlo high pollution advisory days. This regulation

was developed with the support ofthe local OHV industry. See also Clark County Air Quality Regulations, Section 90,which effectively restricts OHV activity on BLM and other open areas greater than 5,000 square feet within the Las Vegas PMlo nonattainrnent area. 44

d. Among other things, it seemsreasonable to expect that ICAPCD's BACM analysis would evaluate the feasibility and impacts of additional restrictions in OHV areas, such as closing

some of the 250 square miles that are particularly likely to impact populations, or restricting OHV activity during summer months when there is virtually no rain to reform surface crusts.

2. Emissions from Unpaved Roads

3. 

### BACM Implementation for Unpaved Non-Farm Roads

4 1 Imperial Sand Dunes Recreation Area Management Plan (RAMP), U.S. DOI, BLM, El Centro Field Office, May 2003, pg. 5. 42 ICAPCD Staff Report, BACM Amendments to Regulation VIII, Fugitive Dust Rules, November 8,2005. 43 Seehttp:!/ww.blin.~ov/ca~st/e~i!pro~~rr:~~'eation/ol~v.lit~nl 44 PMloState Implementation Plan for Clark County, Adopted by Clark County Board of Commissioners, June 19, 2001, pg. 4-81,http://www.accessclarkcounty.com/depts/daqeaq/paminages/pmlOsip2OOl.aspx. 2005 

### PMloEmissions and

Imperial County APCD -RegulationVIII TSD, 02/10 Inventory assumed ADT level taken from Appendix B, 2005 BACM Analysis. Road mileage and estimated annual average emissions from 2009 PMlo SIP, Table 3.2,pg 3-3. Emission reductions from 2009 PMlo SIP, Table 4.1, pg. 4-5



### . Road Category

Cnty <50 ADT Cnty >50ADT



# , City Roads

Canal Roads Federal Roads Farm Roads Total Un2aved Road Emissions Inventory Data 

### Road Miles

1155 199 7.5 6 148

139 2263 7648.5 Rule 805 Threshold (miles) exempt 50 5 0 2 0 5 0



### -- Inventory Assumed 

### ART 10 70 10 5 10



### -- Reg

### VIII Reduction (t~d) 0 8.73

0 0 0 1.11 9.84 Windblown Emissions 

### (tpd) 6.64 1.14 0.03 16.32 0.37 6.01 24.5 Entrained Emissions 

### ad) 11.11 13.4 0.07 29.57

1.35 1.35 55.5As discussed in Section 1.C above, CAA Section 189(b)(l)(B)required BACM implementation in Imperial County by September 10,2008. Despite the September 10,2008BACM implementation requirement, ICAPCD projects that the 199 miles ofunpaved roads subject to Rule 805 will not be stabilized until 2015. This assumes that the County will gravel 19.9miles of unpaved roadway eachyear for ten years beginning in 2006.~'

We recognize that some control measures, such as paving a network ofunpaved roads, may involve significant coststo public entities. EPA has explained that, where economic feasibility of control depends on public funding, we will consider past funding and the future availability of funding sources to determine if a good faith effort is being made to implement BACM expeditiously. For example, an existing unpaved road stabilizationprogram should retain its existing level of funding and the state should provide evidence of ambitious effortsto increase future funding and increase the future priority of the unpaved road stabilizationprogram for existingrevenue streams.46 ICAPCD states that the County budget for paved road maintenance is $2 million per year 47 but does not explain whether this entire amount is to be allocated to the unpaved road stabilizationprogram. Assuming that the entire amount is to be so allocated, ICAPCD does not explainthe relationship between this budget and the schedulefor stabilizing unpaved roads, does not explain how this budget was derived in light of various federal, state, and local (including local Measure D) funding sources for public works construction and maintenance, or otherwise provide the demonstration contemplated by the relevant EPA guidance.
Using the per mile cost figures provided by the Imperial County Department ofPublic Works (ICDPW), and again assuming that the entire $2million annual budget will be used for unpaved road stabilization,we estimatethe costs oftwenty miles of annual road stabilizationin the table below. Since ICAPCDprojects that gravelling will be used predominantly,48it appears only 9% ofthe $2million annual budget would be needed for roadway stabilizationto comply with the ten year schedule in Rule 805 Section E.7. It isnot obvious from the information provided inthe submittal,therefore, why Rule 805 Section E.7 does not require a more expedited schedule.
Estimated Unpaved Road Stabilization Annual Costs

I 

# 1 Control Measure 

## I Costhile 

## / 20 

### mile cost 

## I %ofICDPW

### $2M Budget 

# I

/ Pave 

## / $131,000 

## 1 $2.62 M 

# 1 131%

# /

Cost factors taken from 2009 PMlo Plan, pg. 4-8,. & water

Implementation schedule taken from 2009 PM,oPlan,, Table 1V.C-1,Appendix 1V.C.

45 2009 PMlo SIP, Table 1V.C-I,Appendix 1V.C-1,pg. 1V.C-I. 46 59 FR 42013. 47 2009 PMloSIP, pg. 4-8. We did not find citations for ICAPCD's $2milIion/year budget estimate, such as funding documents or county budgets. 48 2009 PMlo SIP,pg. 4-8, footnote 67. $2,980 $8,950

Imperial County APCD -Regulation Vlll TSD, 02/10 $59,600 $179,000 3% 9%

### 4. Agricultural Windblown Dust

Rule 806 does not require BACM level controls for controlling windblown dust from active or fallow agricultural fields. In general, EPA believes that the evaluation of BACM level controls for a particular source or activity should include considerationofUSDA approved conservation systems and activities. Although these guidelines may not specifically be designed to minimize air pollution, they are intended to be feasible and effective techniques that will reduce windblown dust, and thus would be appropriate measures to consider for BACM for such sources or activities for PMlo. USDA's National Agronomy Manual explainsthat controls for reducing wind erosion should be based onthe followingprinciples.49

a. Establish and maintain adequatevegetation or other land cover. b. Reduce unsheltered distance along the wind erosion direction.

c. Produce and maintain stable clods or aggregates onthe land surface. d. Roughen the land with ridge and/or random roughness.

For active agricultural fields, some CMPs in Rule 806, such as cover crops, are based on these principles and should help control windblown dust. Other CMPs in the rule, such asprecision farming,mainly target entrained dust by reducing the number ofvehicle passes across the field. While Imperial County farms may choose windblown dust control CMPs, they are not required to do so even though BACM for agricultural windblown dust emissions must be implemented in Imperial County as discussed in Section 1I.B above. We note SCAQMD requirements for active agricultural fields below. EPA would expect a meaningful BACM analysis to include a review of windblown dust requirements for active fields in SCAQMD and other areas.

Rule 806 doesnot apply to fallow agricultural fields," and hence cannot provide BACM level controls for these fields. IID currently has a Fallowing Program which compensates volunteer farmers for fallowing. From July 2007 to June 2008, about 16,000 acres were in the 2007-2008 IID Fallowing ~ro~ram." During approximately the same period, between about 27,000 and 32,000 acres were fallow in Imperial County outside ofIID's Fallowing program.j2 While IID's

49 NationalAgronomy Manual, USDA NRCS, October 2002, pg. 502-17. The National Agronomy Manual also lists the following principle which does not seem to be applicable to Imperial sources: "Reshape the land to reduce erosion on knolls where converging windflow causes increased velocity and shear stress." 50 The CMPs from which sources are required to select in order toreduce emissions from on-field sources are for reducing PMlo emissions from land preparation and cultivation (Rule 806 Section E.l) and for reducing PM,, emissions from harvest (Section E.2). If implemented in certain ways, some of the CMPs in these categories, such as cover crop, may also reduce emissions from fields that become fallow. However, there are no requirements in Rule 806 to address emissions from fallow fields. 51 IID's program started in 2003 and will continue until 2017. "Imperial lrrigation District Fallowing Program Status Report," February 19, 2008, on web page http://www.iid.com/Water/FallowingPrograms, direct link: http://www.iid.com/Media~Fallowing-Program-Summary-2003-2008-Presentation.pdf. Seepage 11 for acreage during the 2007-2008 Fallowing Program. 52 See Imperial Irrigation District Water Department Monthly Crop Acreage Report, August 13, 2008, pgs. 13 and 22, for data on fallow acreage outside of IID's program from August 2007 to August 2008. 1ID's Monthly Crop
lmper~al County APCD -Regulation VIII - 17-
TSD, 02110Program requires some dust mitigation, we were unable to identify any requirements for controlling emissions from the fields that are outside IID's program. EPA would expect a meaningful BACM analysis to include a comparison of the requirements that are currently in place for mitigating emissions from fallow fields both within and outside ofIID's program with requirements in other areas, including SCAQMD.
SCAQMD, for comparison, enforces several requirements designed toreduce agricultural windblown dust from active and inactive fields. SCAQMD Rule 403 and the associated handbooks53for the South Coast and Coachella air basins were developed with extensive input from NRCS and the agricultural community and mainly seem based on the principles in USDA's National Agronomy Manual. Among other things, SCAQMD Rule 403 and the associated handbooks require growers to:

a. Cease certain soilpreparation and maintenance activities when winds exceed 

### 25 miles per hour. b. Implement one of four specific practices to reduce windblown dust from actively disturbed fields. Active conservation options include soil moisture monitoring (ensuring soil moisture toprevent visible dust emissions beyond 100 feet), irrigation systems (irrigating or bedding fields as soon as feasible after land leveling to prevent the field being left smooth and dry), minimum tillage and mulching. c. Implement three of nine specific practices to reduce windblown dust from inactive (fallow) fields. Inactive conservation options include cover crop, crop residue management, surface roughness, minimum tillage, cross wind stripcropping, field windbreaks, ridge roughness and wind barriers.



### IV. EPA's Proposed Action

The submitted Regulation VIII rules strengthen the SIP and largely meet the relevant CAA Section 110 and part D requirements, but the deficiencies discussed above preclude full approval. EPA staff recommends a simultaneous limited approval pursuant to CAA Sections 110(k)(3) and 30

### 1(a) and limited disapproval pursuant to Sections 110(k)(3), 11 O(a) and 189(a)(l)(C)and (b)(l)(B) ofthe seven inter-related Regulation VIII rules. If finalized asproposed, the deficiencies identified in Section 1I.D.1ofthis Technical Support Document would trigger CAA Section 179 sanctions and a Section 110federal implementation plan (FIP) obligation. The deficiency identified in Section II.D.2 would not trigger sanctions or a FIP obligation at this time because it does not appear associated with SIPrevisions that are required by the CAA.

Acreage Report, June 13,2007. has similar data for June 2006 through June 2007. IID uses the term 'idle' ifthere is

no crop on the field for less than a year, and codes a field as 'fallow' if it does not have a crop for over a year. 53 The South Coast and Coachella Valley Agricultural Handbooks are relied on for certain compliance options within SCAQMD Rule 403.
Imperial County APCD -Regulation VlII TSD, 02/10