This is a preliminary document prepared by a subgroup member of the Base Programs Analyses and Policies work group as part of the Federal Advisory Committee Act (FACA) Subcommittee process. It is not an EPA document. This document has not been reviewed by the work group and is subject to further work group discussion. Interested people should forward their comments to a member of the Base Programs Analyses and Policies (BPA&P) work group.

Phase II Implementation Strategies for Contingency Measures

Date: May 21, 1997

Status: Revised Draft #4 - Incorporates discussions from the BPA&P work group meeting May 15, 1997.

Contact: Eric Skelton, representing the BPA&P work group @ (509) 456-4727 x121, FAX: (509) 459-6828

Introduction

This paper addresses contingency measures in both attainment and nonattainment areas under the new/revised ozone and PM national ambient air quality standards (NAAQS) as well as the regional haze program.

Background

There are two purposes for contingency measures used in a SIP program. First, contingency measures are used to promptly correct a violation of the NAAQS in a maintenance area after attaining the standard. Second, contingency measures are used to assist a nonattainment area in meeting reasonable further progress (RFP) or to attain the NAAQS by a certain date [sec. 172(c)(9) and sec. 182(c)(9)]. The contingency provisions in Subpart 1 [sec. 172(a)(9)] are the general contingency measures and apply to all SIPs for criteria pollutants. The contingency provisions found in Subpart 2 [sec. 182(c)(9)] were part of the Clean Air Act Amendments of 1990 (CAAA) and apply only to those SIPs for ozone nonattainment areas. The general preamble to implement Title I of the CAAA (57 FR 13498) attempted to suggest what should be in the list of contingency measures (i.e., 3 percent of VOC or NOX) however, there was never a clear definition as to how much correction would be triggered.

In practice, contingency measures have required the implementation of some new reductions that at face value seem sufficient to correct the problem. The new/revised standards are proposed to be covered under the Subpart 1 contingency provisions. How the new/revised standards relate to Subpart 2 contingency provisions [sec. 182(c)(9)] will be discussed in greater detail as part of the issues.

Contingency Measures for Nonattainment Areas or Areas of Violation

Historically contingency measures have been defined as specific measures to be undertaken if a nonattainment area fails to make RFP, or to attain the NAAQS (i.e., ozone or PM-10) by the applicable attainment date. These contingency measures are included in a State's SIP. Reductions must be achieved promptly (i.e., in the year following that in which the failure was identified).

For ozone, under Subpart 2, contingency measures must be fully adopted rules or measures. The measures do not have to be implemented unless and until they are triggered, either by failure to meet a milestone in RFP or to attain the NAAQS. The SIP should clearly state the trigger mechanisms, a schedule of the implementation of the measures, and an indication that the measures will be implemented with no further action by the State or EPA. Contingency measures prior to November 15, 1996 (pre-1996), had to address VOC reductions while post-1996 contingency measures could address reductions for VOC and/or NOX. EPA allows for the post-1996 contingency measures to provide for less than 3 percent in VOC reductions as long as the difference is made up in NOX reductions. Examples of ozone contingency measures include, but are not limited to, Stage II vapor recovery, enhanced inspection/maintenance programs, and VOC control on minor (i.e., less than 100 tons per year) new sources.

PM-10 contingency measures generally have no set rules other than allowing the area to regain RFP or attain the PM-10 NAAQS. Examples of PM-10 contingency measures include, but are not limited to, substituting liquid deicers for sand and/or road salt, and implementing residential wood combustion (RWC) curtailment programs.

Contingency Measures for Attainment Areas

1. Areas Redesignated as Attainment for the NAAQS

When a State submits a request to EPA to redesignate a nonattainment area to attainment for a particular pollutant, the package must contain an approvable maintenance plan. The maintenance plan constitutes a SIP revision and must provide for maintenance of the NAAQS in the area for at least 10 years after redesignation. Eight years after the original redesignation request is approved, the area must submit a revision to the SIP to provide for maintenance of the NAAQS for an additional 10 years following the first 10-year period. The maintenance plan contains contingency measures to ensure prompt correction of any violation of the NAAQS that might occur after redesignation to attainment.

When the redesignated area has violated the relevant NAAQS, contingency measures listed in the maintenance plan are invoked to make prompt corrections that will bring the area back into attainment. There are two types of contingency measures which can be used in the maintenance plan.

The first types of contingency measures are statutorily-mandated control programs that were not implemented prior to submittal of the redesignation request. In this case, EPA allows the State to move these measures from the implemented SIP to the contingency measures portion of the SIP provided the State demonstrates that such measures are not needed for maintaining the NAAQS. These contingency measures can then be folded into the maintenance plan for the area. Certain specific programs, such as basic I/M, were required to be adopted by the state and approved by EPA in order for the State to have a fully approved SIP. EPA will accept, in lieu of actual adoption, legislative authority for such programs and allow such measures to be placed as contingency measures in the maintenance plan, provided the State demonstrates such measures are not needed to maintain the NAAQS.

The second type of contingency measures initially do not need to be fully adopted and can simply be listed. However, the contingency measures in the maintenance plan are considered an enforceable part of the SIP, and the measures must be adopted expediently once they are triggered. The maintenance plan identifies the specific triggers or indicators used, the specific measure(s) to be adopted, a schedule and procedure for adoption and implementation of the measure, and a specific time limit for action by the State.

2. Areas Always in Attainment with the NAAQS

These are the areas that have always attained the standard and are included in the maintenance SIPs submitted to EPA in 1972. As a rule, these SIPs do not include contingency measures to correct any violation of the standard.

ISSUES

1. Should contingency measures be episodic? Should episodic contingency measures be included in the core measures for the SIP? In the past, episodic measures were part of "emergency episode" plans during the 1960's and 1970's. These measures were designed primarily for point sources during higher levels of air quality alerts. Since then many of the point sources have continuous emission controls as a result of the CAA. Thus today, episodic measures have a better potential to obtain additional emission reductions when applied to area and mobile sources of emissions than to point sources of emissions. This does not preclude the use of episodic control strategies (e.g., production curtailment or temporary process shut-down) on a point source especially if the source is well controlled to start with and the next level of continuous control should prove to be cost prohibitive.

Ozone strategies, according to EPA guidance, were required to be real, permanent, quantifiable, and enforceable. Episodic strategies traditionally have not been viewed as providing real, permanent, quantifiable, and enforceable emissions reductions, and therefore have not been considered as approvable for the contingency measure requirement under the existing NAAQS. Section 123 of the Clean Air Act forbids credit being given in a SIP demonstration when the emission stack height exceeds good engineering practices or the source uses other dispersion techniques such as episodic controls.

Currently, many western states have seasonal residential wood combustion (RWC) curtailment programs that curtail all wood burning except for sole-source heating as a means of controlling particulate matter emissions. Such seasonal programs have proved successful and have subsequently been adopted in the SIP. These programs are generally triggered by the ambient concentration of PM-10 reaching a certain threshold (approximately 90 to 110 g/m3) and generally last for 24 hours or until temperature inversion conditions dissipate. An exemption from the current interpretation of section 123 for this use of an episodic control strategy as well as emissions from agricultural and silvicultural prescribed burning, and open burning is provided in the definitions of "EPA Regulations on Preparation of Implementation Plans" [40 CFR 51.100(hh)(2)(iii) and (iv)].

Pros: Episodic measures should be used to supplement permanent contingency measures. Episodic measures can achieve desired results in a more cost effective manner than what could be achieved with year round controls. Some episodic measures may prove effective over time as public attitudes/awareness changes.

Cons: There is some difficulty in predicting when episodic control measures are needed. In order to respond in a timely fashion, the threshold ambient concentration has to be set relatively low. This can result in a number of false positives (i.e., an area predicts a potential exceedance of the standard and episodic measures are implemented when the standard would not have been exceeded if the area did not take any actions). In most cases, if the standard is not exceeded after the episodic measure is implemented, the area cannot say with certainty that implementation of episodic measures kept the area in attainment or whether other factors (i.e., meteorology) prevented the violation. Modeling tools are available today which allow an area to reasonably predict ambient concentrations to avoid exceedances of the standard. With experience, certain modeling parameters (i.e., temperature, atmospheric stability) could be used as a more simple surrogate to determine when to trigger episodic control conditions.

2. To what degree should voluntary measures be included as contingency measures? For each AOI/AOV or nonattainment area, there is a core set of prescribed measures that are designed to bring the area into attainment with the standard. There may be some circumstances in which these measures may not get the area to attainment but rather close to attaining the standard. In this situation, voluntary measures may provide enough reductions to bring the area the rest of the way to attaining the standard. Should there be a progressively stricter test, depending on status of area (e.g., always attainment, redesignated attainment, or nonattainment), to determine the extent of credit to be claimed in the SIP for voluntary measures. Examples of voluntary measures include, but are not limited to, no-drive days on ozone alert days.

Pros: Voluntary measures should be used to supplement enforceable contingency measures. Voluntary measures can achieve desired results in a more cost effective manner than what could be achieved with mandatory controls. Some voluntary measures may prove effective over time as public attitudes/awareness changes. Voluntary measures can increase the public's understanding of their role in abatement as people make conscious choices to "buy into" the programs.

Cons: One of the work group members suggested that voluntary measures are "window dressing" serving only to make people feel good. States cannot tell ahead of time how effective a voluntary measure would be. Voluntary measure are not enforceable. Providing credit for voluntary programs may not be permissible under the Act.

3. What is the time frame for adoption of contingency measures in newly designated nonattainment areas? In the past, ozone SIPs were required to be submitted by November 1993. EPA allowed the States to submit contingency measures by November 1994. Will comparable separate submittal dates be allowed for the new/revised standards for ozone and PM-fine as well as regional haze?

Option 1. Allow a longer period of time.

Pros: Allow the area to determine what is needed for contingency measures. The area may not know the effect of the core SIP measures until they have been implemented, given the current state of understanding of secondary pollutant formation. Until the area knows the effectiveness of these measures, the area cannot develop contingency measures with certainty as to their effectiveness to solve the problem.

Cons: If the areas are allowed a long lead time and contingency measures are not in place, the area will have nothing to fall back on if it violates the standard or misses a RFP milestone.

Option 2. Allow a shorter period of time.

Pros: Contingency measures would be ready in a short period of time. This would provide the area with a fall back position if the area violates the standards or misses a RFP milestone.

Cons: The area may adopt contingency measures which may not provide enough emission reductions or the wrong type of emission reductions.

4. Is an area that implements contingency measures early, to avoid a violation of the new/revised standard, required to backfill with additional contingency measures? [Note: The Helms memorandum suggested that nonattainment areas should not have to backfill. EPA has applied this reasoning to both maintenance and nonattainment areas.]

Option 1. The area is required to backfill with additional contingency measures.

Pros: Contingency measures would be ready to implement if needed by the area.

Cons: There will be additional resources expended to develop additional contingency measures. The area may develop contingency measures that may not be needed.

Option 2. The area is not required to backfill with additional contingency measures.

Pros: The area can use the resources that would have been used to develop additional contingency measures for other attainment issues.

Cons: The area may not have contingency measures available as a fall back position if there is a violation of the standard or a missed RFP milestone.

5. Could a contingency measure be used to expand the area of an AOI and broaden the applicability of the control measures? There are two possible scenarios for this issue. The first scenario would involve a multi-jurisdictional expansion of the AOI (i.e., interstate or intrastate) that would make the requirements of the original area apply to the sources in the newly expanded area. The second scenario would have a State during the SIP development process apply a control measure to those sources closest (e.g., within a mile radius) to the AOV. The contingency measure would specify that the control measure will apply to: (1) an increased radius of applicability from the AOV (e.g., increase to a 2 mile radius); (2) apply the control measure to the predominant upwind area from the AOV; or (3) an AOI-wide applicability of the control measure.

Pros: This would allow the expeditious implementation of control measures on applicable new sources in the expanded area of the AOI.

Cons: All the control measures in the original AOI may not be necessary for the sources in the expanded AOI. The AOI may have only needed to control the major sources in the expanded area. This may result in the AOI over controlling the sources included in the area. Could result in delays in implementing initial reductions to increase the area from which to obtain reductions and lessen the burden on sources in the original area. In the case of a multi-jurisdictional expansion of the AOI between 2 states (e.g., the AOV in one state wishing the include sources in a neighboring state that were not included in the original boundaries of the AOI), there would need to be an agreement up front in the RIP development stage (i.e., MOU) that would allow this to happen.

6. Will contingency measures be required for Class I areas for visibility purposes? Areas that do not achieve the reasonable progress goal will have specific measures and a time frame to meet the goal. Contingency measures may be a means to get the area back on track if it deviates from the implementation plan. This issue is addressed in the Regional Haze issue paper.

7. How much emission reduction is required for contingency measures? While the general preamble tried to guess at what should be in the list of available contingency measures (3 percent VOC or NOX), there was never a clear definition as to how much correction would be triggered. In the context of the RFP discussions for the new/revised standard, the general idea of contingency measure seems to be a process that first triggers a set of reductions, and at the same time initiates an analysis to determine the seriousness of the problem. Additional reductions may be implemented to supplement what is required to ensure full correction of the problem. In practice, contingency measures have basically required the implementation of some new reductions that at face value seem sufficient to correct the problem.

Option 1. The contingency measure with unspecified emissions reduction credit. Cannot quantify the amount of emissions reduction, but continues progress in the right direction.

Pros: Very simple to develop a contingency measure that can claim progress.

Cons: No accountability. The contingency measure may not make much progress to attain the standard. The area may develop a contingency measure that in effect achieves little or no real progress.

Option 2. The contingency measure must achieve some quantifiable percentage of emission reductions or reduction of some portion of VMT growth.

Pros: Progress is real and quantifiable. The contingency measure would result in specific measurable progress.

Cons: Areas may be hard pressed to develop measures that will demonstrate quantifiable progress, given the difficulty in developing the core measures.

8. Should there be a mechanism to allow substitution of equivalent measure(s) in lieu of SIP-planned contingency measures? Potential equivalent measures could include, but may not be limited to, Inspection and Maintenance (I/M) 240 program, national measures such as the acid rain program or the Department of Transportation developing new fuel efficiency standards.

Pros: Substitution of equivalent measures would allow areas to bank the contingency measure until implementation of the contingency measures becomes absolutely necessary.

Cons: Substitution of equivalent measures has the potential of becoming an equity issue. There is the possibility that some areas will be able to take advantage of this option while other areas, through no fault of their own, will be unable to substitute equivalent measures.

9. Should measures that were used by an area to bring it into attainment be dropped from the maintenance plan? If an area drops a measure from a maintenance plan, the area must roll the measure over as a contingency measure and provide a technical demonstration showing the measure is no longer needed for maintenance. If a nonattainment area contingency measure(s) [under sec. 172(c)(9)] helps bring an area to attainment, the measure(s) should continue to be used in the maintenance plan in the event the area wishes to redesignate to attainment. If the State shows the measure is not needed to maintain the standard, it can be rolled over as a contingency measure in the maintenance plan.

10. Should there be federally prescribed contingency measures for attainment and/or maintenance plans? Not referring to the rolling over of unimplemented prescribed measures into the contingency category, but rather the EPA formulation of measures that should be used as contingencies.

Pros: Federally prescribed contingency measures will provide national consistency. This will level the playing field across nonattainment areas.

Cons: The contingency measures promulgated by EPA may not be the right measures for all areas. To correct this, EPA will need to incorporate the concept of "rebuttable presumption" in each contingency measure.

[Note: Refer to flow chart for the NAAQS Implementation Process under "Promulgate National Measures."]