Federal Register: October 28, 2009 (Volume 74, Number 207)
DOCID: fr28oc09-15 FR Doc E9-25454
ENVIRONMENTAL PROTECTION AGENCY
Treasury Department
CFR Citation: 40 CFR Parts 9 and 63
RIN ID: RIN 2060-AO55
EPA ID: [EPA-HQ-OAR-2003-0146; FRL-8972-4]
NOTICE: Part III
DOCID: fr28oc09-15
DOCUMENT ACTION: Final rule.
SUBJECT CATEGORY:
National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries
DATES: The final amendments are effective on October 28, 2009. The incorporation by reference of certain publications listed in the final rule amendments is approved by the Director of the Federal Register as of October 28, 2009.
DOCUMENT SUMMARY:
This action amends the national emission standards for petroleum refineries to add maximum achievable control technology standards for heat exchange systems. This action also amends the general provisions crossreference table and corrects section references.
SUMMARY:
Environmental Protection Agency
SUPPLEMENTAL INFORMATION
The information in this preamble is organized as follows:
I. General Information
A. Does this action apply to me?
B. Where can I get a copy of this document?
C. Judicial Review
II. Background Information
III. Summary of the Final Amendments to NESHAP for Petroleum Refineries and Changes Since Proposal
A. What requirements for heat exchange systems are we promulgating pursuant to CAA section 112(d)(2)?
B. What other revisions and clarifications are we making?
C. What is the compliance schedule for the final amendments? IV. Summary of Comments and Responses
A. Heat Exchange Systems
B. General Provisions Applicability
V. Summary of Impacts
VI. Statutory and Executive Order Reviews
A. Executive Order 12866: Regulatory Planning and Review
B. Paperwork Reduction Act
C. Regulatory Flexibility Act
D. Unfunded Mandates Reform Act
E. Executive Order 13132: Federalism
F. Executive Order 13175: Consultation and Coordination With Indian Tribal Governments
G. Executive Order 13045: Protection of Children From Environmental Health Risks and Safety Risks
H. Executive Order 13211: Actions Concerning Regulations That Significantly Affect Energy Supply, Distribution, or Use
I. National Technology Transfer and Advancement Act
J. Executive Order 12898: Federal Actions To Address
Environmental Justice in Minority Populations and LowIncome Populations
K. Congressional Review Act
I. General Information
A. Does this action apply to me?
The regulated category and entities potentially affected by this final action include:
Examples of regulated
Category NAICS \1\ code entities
Industry...................... 324110........... Petroleum refineries
located at a major
source that are
subject to 40 CFR
part 63, subpart CC. \1\ North American Industry Classification System.
This table is not intended to be exhaustive, but rather provides a guide for readers regarding entities likely to be regulated by this final rule. To determine whether your facility is regulated by this action, you should carefully examine the applicability criteria in 40 CFR 63.640 of subpart CC (National Emission Standards for Hazardous Air Pollutants From Petroleum Refineries). If you have any questions regarding the applicability of this action to a particular entity, contact either the air permit authority for the entity or your EPA regional representative as listed in 40 CFR 63.13 of subpart A (General Provisions).
B. Where can I get a copy of this document?
In addition to being available in the docket, an electronic copy of this final action will also be available on the Worldwide Web through the Technology Transfer Network (TTN). Following signature, a copy of this final action will be posted on the TTN's policy and guidance page for newly proposed or promulgated rules at the following address: http://www.epa.gov/ttn/oarpg/. The TTN provides information and technology exchange in various areas of air pollution control. C. Judicial Review
Under section 307(b)(1) of the Clean Air Act (CAA), judicial review of this final rule is available only by filing a petition for review in the United States Court of Appeals for the District of Columbia Circuit by December 28, 2009. Under section 307(d)(7)(B) of the CAA, only an objection to these final rules that was raised with reasonable specificity during the period for public comment can be raised during judicial review. Moreover, under section 307(b)(2) of the CAA, the requirements established by these final rules may not be challenged separately in any civil or criminal proceedings brought by EPA to enforce these requirements.
Section 307(d)(7)(B) of the CAA also provides a mechanism for us to
convene a proceeding for reconsideration, ``[i]f the person raising an
objection can demonstrate to the EPA that it was impracticable to raise
such objection within [the period for public comment] or if the grounds for such objection
[[Page 55671]]
arose after the period for public comment (but within the time
specified for judicial review) and if such objection is of central
relevance to the outcome of the rule.'' Any person seeking to make such
a demonstration to us should submit a Petition for Reconsideration to
the Office of the Administrator, Environmental Protection Agency, Room
3000, Ariel Rios Building, 1200 Pennsylvania Ave., NW., Washington, DC
20460, with a copy to the person listed in the preceding FOR FURTHER
INFORMATION CONTACT section, and the Associate General Counsel for the
Air and Radiation Law Office, Office of General Counsel (Mail Code
2344A), Environmental Protection Agency, 1200 Pennsylvania Ave., NW., Washington, DC 20460.
II. Background Information
Section 112 of the CAA establishes a regulatory process to address emissions of hazardous air pollutants (HAP) from stationary sources. After EPA has identified categories of sources emitting one or more of the HAP listed in section 112(b) of the CAA, section 112(d) calls for us to promulgate national emission standards for hazardous air pollutants (NESHAP) for those sources. For ``major sources'' that emit or have the potential to emit any single HAP at a rate of 10 tons or more per year or any combination of HAP at a rate of 25 tons or more per year, these technologybased standards must reflect the maximum reductions of HAP achievable (after considering cost, energy requirements, and nonair quality health and environmental impacts) and are commonly referred to as maximum achievable control technology (MACT) standards.
For MACT standards, the statute specifies certain minimum stringency requirements, which are referred to as floor requirements. See CAA section 112(d)(3). Specifically, for new sources, the MACT floor cannot be less stringent than the emission control that is achieved in practice by the bestcontrolled similar source. The MACT standards for existing sources can be less stringent than standards for new sources, but they cannot be less stringent than the average emission limitation achieved by the bestperforming 12 percent of existing sources in the category or subcategory (or the bestperforming five sources for categories or subcategories with fewer than 30 sources). In developing MACT, we must also consider control options that are more stringent than the floor. We may establish standards more stringent than the floor based on the consideration of the cost of achieving the emissions reductions, any nonair quality health and environmental impacts, and energy requirements.
We published the final MACT standards for petroleum refineries (40 CFR part 63, subpart CC) on August 18, 1995 (60 FR 43620). These standards are commonly referred to as the ``Refinery MACT 1'' standards because certain process vents were excluded from this source category and subsequently regulated under a second MACT standard specific to these petroleum refinery process vents (40 CFR part 63, subpart UUU, referred to as ``Refinery MACT 2'').
In developing this rule, we first issued an advanced notice of
proposed rulemaking (ANPR) on March 29, 2007. The purpose of the ANPR,
which covered the sources subject to the Refinery MACT 1 rule and other
source categories, was to solicit additional emissions data and any
corrections to the data we already had. We issued an initial proposed
rule for the petroleum refineries subject to the Refinery MACT 1 on
September 4, 2007, and held a public hearing in Houston, Texas, on
November 27, 2007. In response to public comments on the initial
proposal, we collected additional information and revised our analysis
of the MACT floor. Based on the results of these additional analyses,
we issued a supplemental proposal on November 10, 2008, that
established a new MACT floor for heat exchange systems. A public
hearing for the supplemental proposal was held in Research Triangle
Park, North Carolina, on November 25, 2008. We are now taking final
action to establish standards for heat exchange systems in the Refinery
MACT 1 standards (40 CFR part 63, subpart CC) and to update and amend Table 6 to 40 CFR part 63, subpart CC.\1\
\1\ We were also required by a Consent Decree to consider and
address the application of the NESHAP General Provisions in 40 CFR
part 63, subpart A to the existing Refinery MACT 1 rule (subpart CC).
III. Summary of Final Amendments to NESHAP for Petroleum Refineries and Changes Since Proposal
A. What requirements for heat exchange systems are we promulgating pursuant to CAA section 112(d)(2)?
On September 4, 2007, we proposed, under CAA section 112(d)(2), two options for work practice standards for cooling towers: Option 1 was proposed based on our initial assessment of the MACT floor and Option 2 was a beyondthefloor option. These options would require the owner or operator of a new or existing source to monitor for leaks in the cooling tower return lines from heat exchangers in organic HAP service (i.e., lines that contain or contact fluids with 5 percent by weight or greater of total organic HAP listed in Table 1 of the rule) and, where leaks are detected, to repair such leaks within a specified period of time.
On November 10, 2008, we issued a supplemental proposal that significantly modified the proposed monitoring methods, leak definitions, and corrective action timeframe based on a revised MACT floor and beyondthefloor analysis. In the supplemental proposal, we also redefined the requirements in terms of heat exchange systems to include the heat exchangers, for which corrective actions are targeted, as part of the source and to specifically address oncethrough cooling systems.
After considering public comments, for purposes of establishing MACT under CAA section 112(d)(2), we have selected the MACT floor requirements specified in the supplemental proposal for heat exchange systems in organic HAP service at petroleum refineries. We rejected the beyondthefloor option because it is not costeffective.
Under these selected requirements, owners and operators of heat
exchange systems that are in organic HAP service at new and existing
sources are required to conduct monthly sampling and analyses using the
Texas Commission on Environmental Quality's (TCEQ) Modified El Paso
Method, Revision Number One, dated January 2003.\2\ For existing
sources, a leak is defined as 6.2 parts per million by volume (ppmv)
total strippable volatile organic compounds (VOC) in the stripping gas
collected via the Modified El Paso Method. For new sources, a leak is
defined as 3.1 ppmv total strippable VOC collected via the Modified El
Paso Method. The amendments require the repair of leaks in heat
exchangers in organic HAP service within 45 days of the sampling event
in which the leak is detected, unless a delay in repair is allowed.
Delay in repair of the leak is allowed until the next shutdown if the
repair of the leak requires the process unit served by the leaking heat
exchanger to be shut down and the total strippable VOC concentration is
less than 62 ppmv. Delay in repair of the leak is also allowed for up to 120 days
[[Page 55672]]
if the total strippable VOC concentration is less than 62 ppmv and if
critical parts or personnel are not available. The owner or operator is
required to continue monthly monitoring and to repair the heat
exchanger within 30 days if sampling results show that the leak exceeds 62 ppmv total strippable VOC.
\2\ ``Air Stripping Method (Modified El Paso Method) for
Determination of Volatile Organic Compound Emissions from Water
Sources,'' Revision Number One, dated January 2003, Sampling
Procedures Manual, Appendix P: Cooling Tower Monitoring, prepared by
Texas Commission on Environmental Quality, January 31, 2003 (incorporated by referencesee Sec. 63.14).
Sampling for leaks can be done for individual or combined heat exchangers. For heat exchange systems including a cooling tower, sampling can be conducted at the combined cooling tower inlet water location. Similarly, for oncethrough heat exchange systems, the sampling can be conducted after the heat exchanger water is combined and prior to discharge where it will be open to atmosphere. For both cooling tower and oncethrough heat exchange systems, sampling can be conducted at individual heat exchangers in the return or ``exit'' lines (i.e., water lines returning the water from the heat exchangers to the cooling tower or to the discharge point). That is, if the cooling tower or oncethrough system services multiple heat exchangers, the owner or operator may elect to monitor only the heat exchangers ``in organic HAP service'' or monitor at branch points that combine several heat exchanger exit lines, or monitor at the combined stream for the entire system. If a leak is detected (the measured VOC concentration exceeds the applicable leak definition) at the combined cooling tower inlet or oncethrough system, the owner or operator may either fix the leak (reduce the VOC concentration to less than the applicable leak definition) or sample heat exchanger exit lines for combinations of heat exchanger exit lines or sample each heat exchanger ``in organic HAP service'' as necessary to document that the leak is not originating from a heat exchanger ``in organic HAP service.'' If a leak is detected in an individual heat exchanger ``in organic HAP service,'' that leak must be repaired.
All new or existing refineries with a heat exchange system ``in organic HAP service'' are required to maintain records of all heat exchangers and which of those heat exchangers are in organic HAP service, the cooling towers and oncethrough systems associated with heat exchangers in organic HAP service, monthly monitoring results, and information for any delays in repair of a leak.
These requirements will apply to sources on a continuous basis, including periods of startup, shutdown, and malfunction (SSM). As provided in the response to comments below, properly operating heat exchangers will not leak HAP into the cooling water, so HAP will not be emitted from the cooling tower or oncethrough discharges. It is only when they malfunction (i.e., there are leaks) that there may be HAP emissions. The MACT standard for heat exchange units addresses these emissions. Furthermore, there are no HAP emissions associated with startup and shutdown.
The requirements outlined above are based on the MACT floor determination. We evaluated the following beyondthefloor options: having a leak definition of 3.1 ppmv for existing sources (beyondthe floor option for existing sources) and requiring continuous monitoring (beyondthefloor options for both new and existing sources). As described in our supplemental proposal, we determined that these beyondthefloor options were not costeffective and concluded that MACT was the floor level of control.
The final MACT requirements for heat exchange systems will reduce HAP emissions by 630 tons per year (ton/yr). The final requirements for heat exchange systems will also reduce VOC emissions by 4,100 ton/yr. Reducing VOC emissions may provide the added benefit of reducing ambient concentrations of ozone and may reduce fine particulate matter. The annualized nationwide cost impacts of these final standards for heat exchange systems are estimated to be $3.0 million. Our economic analysis indicates that this cost will have little impact on the price and output of petroleum products.
B. What other revisions and clarifications are we making?
As proposed, we are amending 40 CFR 63.650(a) of subpart CC to replace ``gasoline loading racks'' with ``Group 1 gasoline loading racks'' to clarify the applicability of the requirements. Furthermore, as we proposed on November 10, 2008, we are also finalizing proposed amendments to the crossreferences to subparts R and Y of 40 CFR part 63 in the rule text and in Tables 4 and 5 of subpart CC because subparts R and Y were amended and the revised crossreferences clarify the requirements of subpart CC.
We are finalizing amendments to Table 6 to 40 CFR part 63, subpart CC (General Provisions Applicability to Subpart CC) to bring the table uptodate with requirements of the General Provisions that have been amended since this table was created, to correct crossreferences, and to incorporate additional sections of the General Provisions that are necessary to implement other subparts that are crossreferenced by this rule. With respect to the exemption from emission standards during periods of SSM in the General Provisions (see, e.g., 40 CFR 63.6(f) and (h)), we note that on December 19, 2008, in a decision addressing a challenge to the 2002, 2004, and 2006 amendments to those provisions, the Court of Appeals for the District of Columbia Circuit vacated the SSM exemption. Sierra Club v. EPA (D.C. Cir. No. 021135).
The CAA section 112(d)(2) and (3) MACT standard we are promulgating today for heat exchange systems is not implicated by that decision because it does not rely on or reference the provisions of the vacated rule and because the MACT standard applies at all times. We are amending Table 6 to clarify that the MACT standard for heat exchange systems applies at all times.
We are still evaluating the recent court decision. At this time, we are not making any additional changes to Table 6 with respect to the SSM provisions in 40 CFR 63.6(f)(1) and (h)(1). We have completed our initial assessment of the General Provisions and their application to subpart CC of part 63. The recent court decision requires further analysis, and we are currently evaluating how to address SSM events for Refinery MACT 1 sources in light of the court decision.
We are also finalizing amendments to Table 1 and Table 7 to delete methyl ethyl ketone (also known as 2butanone) from the HAP listed in those tables because methyl ethyl ketone has been delisted as a HAP. We are finalizing amendments to clarify the applicability sections by changing general references to ``the promulgation date'' to specify the actual promulgation date of the original subpart CC of part 63. Finally, we are also finalizing amendments to clarify how owners and operators should comply with overlapping standards for equipment leaks. C. What is the compliance schedule for the final amendments?
The final amendments to the Refinery MACT 1 rule will be effective
on October 28, 2009. Under section 112(i)(1) of the CAA, any new
facility must comply upon startup or on the effective date of the rule,
whichever is later. For purposes of determining compliance with these
amendments, a new source is a source that commenced construction or
reconstruction after September 4, 2007 (the initial date of proposal
for these regulations). Consistent with the requirements of CAA section
112(1)(3), the owner or operator of an existing source (including an
existing source for these amendments that is currently subject to 1995
Refinery MACT 1 standards for new sources) must comply with the heat exchange system requirements no later than
[[Page 55673]]
October 29, 2012. The basis for the 3year compliance period is set forth below in our responses to comment.
IV. Summary of Comments and Responses
This preamble and the document ``National Emission Standards for Hazardous Air Pollutants from Petroleum Refineries: Background Information for Final Standards for Heat Exchange SystemsSummary of Public Comments and Responses'' (``Response to Comments'') located in the docket (Docket ID No. EPAHQOAR20030146) include only comment summaries and responses to issues related to heat exchange systems and other clarifying amendments. The major comments on those issues and our responses are summarized in the following sections. A summary of the remainder of the comments and responses related to those issues can be found in the Response to Comments document.
Comments regarding other issues raised as a result of the proposed and supplemental proposed rules are not included in this preamble or the Response to Comments document; they will be addressed, as appropriate, in future rulemakings addressing the residual risk and technology reviews for Refinery MACT 1.
A. Heat Exchange Systems
On November 10, 2008, we issued a supplemental proposal with our revised MACT floor and beyondthefloor analysis. In general, the comments received on the cooling tower requirements initially proposed on September 4, 2007, either have been addressed through the supplemental proposal or are not applicable to the final standards (e.g., clarifications to monitoring methods no longer required). Any general comments regarding cooling tower requirements received on the initial proposal that are still applicable are summarized in the Response to Comments document located in the docket (Docket ID No. EPA HQOAR20030146). Significant comments received on the supplemental proposal are addressed in this section.
1. MACT Floor for Heat Exchange Systems
Comment: A few commenters noted that the leak definition proposed for new heat exchange systems of 3.1 ppmv has not been ``demonstrated in practice.'' One commenter stated that the leak definition of 3.1 ppmv was developed by the State of Texas from the AP42 emission factor. The commenter stated that only one cooling tower is operating under a permit with that limit (the other cooling towers are under construction), and this cooling tower has only recently begun operating, so there is no significant experience operating with the identified new source limit or applying it to the range of operations and ages of exchangers in a typical refinery. The commenter asserted that some heat exchangers and heat exchange systems are difficult to control, and different leak definitions are appropriate for different situations within an individual refinery, so a set of requirements must be demonstrated to be workable on multiple heat exchange systems of varying services and ages before that set of requirements can be considered ``demonstrated in practice.'' Another commenter stated that there is no demonstration that there is technology that can be applied to new sources that improves the emission performance of these systems when considered across the operating life of the facilities. Both commenters recommended setting the new source and existing source requirements equivalent at 6.2 ppmv. (One of the commenters noted that EPA's analysis shows that the next best controlled source has a limit of 5 ppmv, but the commenter noted that there is not much difference between the reductions achieved by a leak definition of 5 ppmv and a leak definition of 6.2, and 5 ppmv is not costeffective. The commenter urged EPA to review cooling towers and heat exchange systems under CAA sections 112(d)(6) and 112(f)(2) and consider factors such as cost rather than developing a standard under CAA section 112(d)(2).)
One commenter noted that in the State of Texas, if a particular cooling tower cannot meet its normal leak definition of 80 parts per billion by weight (ppbw) VOC in the water, the State allows that source to set a leak definition of up to 150 ppbw VOC in the water. For flexibility when dealing with continuous small seepage or situations where the particular HAP or VOC present are not completely stripped by the cooling tower, the commenter suggested that in any 1year period, if monitoring shows three leaks above 6.2 ppmv, but below 12 ppmv, EPA should allow that source to set a new leak definition of 12 ppmv.
Commenters stated that the leak definition of 6.2 ppmv VOC in the stripping gas is not stringent enough. One commenter noted that during cooling tower leak investigations conducted by the City of Houston and TCEQ, a potential leak measured at 2 ppm required sampling by summa canister to confirm the leak, and EPA's regulation should be at least that stringent. The commenter stated that a stringent leak threshold of 2 ppm will ensure that small leaks are found and repaired quickly, especially since the TCEQ leak threshold is 50 parts per billion by volume (ppbv).
Several commenters supported using the Modified El Paso Method to detect leaks but suggested that cooling towers that have higher recirculation flow rates should have lower leak definitions than cooling towers with lower flows because the large cooling towers will have higher mass emissions at the same leak concentration.
Commenters stated that EPA failed to consider the TCEQ Highly Reactive VOC (HRVOC) rule in establishing the MACT floor. The commenters believe the HRVOC rule is applicable to several refinery cooling towers, requires continuous monitoring, and it has a more stringent leak definition and leak repair schedule. One commenter also cited a California refinery that is required to install and operate a continuous hydrocarbon analyzer and repair leaks above an agreed threshold.
Response: The TCEQ El Paso Method has been demonstrated at numerous refineries and other similar sources as an effective means of identifying leaks in heat exchange systems. The method has been used extensively for over 20 years. As suggested by some commenters, the detection limit of the El Paso Method is generally less than 2 ppmv, so leaks of 3.1 ppmv are quantifiable. Ongoing monitoring at refineries indicates that, when no leaks are present or after repairs are made, El Paso monitoring is able to detect leaks well below this leak threshold. As such, the monitoring method and the corrective action measures have been adequately demonstrated.
In criticizing our new source leak definition of 3.1 ppmv, the
commenter recognizes that heat exchangers connected to one refinery
cooling tower are subject to a monitoring program with a leak
definition of 3.1 ppmv. Section 112(d)(3) of the CAA provides that new
source MACT cannot be less stringent than ``the emission control that
is achieved in practice by the best controlled similar source.'' The
commenter's concern that the facility has only recently begun operation
and that there is not ``significant'' experience with the leak
definition of 3.1 ppmv does not change the fact that this level is
being achieved in practice and thus is the appropriate new source MACT
floor. To the extent that the commenter suggests that the cooling
towers meeting this limit are different and thus is presumably arguing that they must be subcategorized, the
[[Page 55674]]
commenter failed to submit any data supporting such a claim. As one
commenter suggested, we cannot set the new source limit at 6.2 ppmv
because we are establishing these requirements under CAA section
112(d)(2), and we cannot consider cost in setting the MACT floor. The
requirements for heat exchange systems are appropriately developed
under CAA section 112(d)(2) because a MACT standard had not been previously developed for this emissions source.
One commenter noted that the TCEQ allows some discretion in setting the total strippable VOC concentration limit or altering the limit based on the performance history of the cooling tower. We do recognize that the cooling tower leak definitions for total strippable VOC required in Texas refinery permits varied from 40 ppbw (or 3.1 ppmv) to 280 ppbw (22 ppmv), including within this range leak definitions at 60 ppbw, 80 ppbw, 150 ppbw, and 180 ppbw, but the 6th percentile facility had a leak definition of 80 ppbw, or 6.2 ppmv total strippable organics as methane. While some permits issued by TCEQ contain language that allows an alteration request or a permit amendment application, as the commenter noted, the permit issued for the 6th percentile cooling tower did not include this type of permit condition. As we cannot establish a requirement less stringent than the MACT floor, we do not provide a 12 ppmv leak definition under any circumstances.
Most of the commenters requesting lower leak definitions appear to misunderstand the stringency of the requirements for heat exchange systems included in the supplemental proposal. Based on the liquid and air flow rates specified in the TCEQ El Paso Method, and with the VOC measurements made as methane as required in the State permits and the supplemental proposal, a 3.1 ppmv VOC concentration in the gas stream from the El Paso stripping column is equivalent to 40 ppbw of strippable VOC (as methane) in the cooling water. The 6.2 ppmv leak threshold translates to a strippable VOC (as methane) in the cooling water of 80 ppbw.
The TCEQ HRVOC rule sets an action level that is 50 ppbw in the cooling water, not 50 ppbv in the stripping air as the commenter suggested. As such, the TCEQ HRVOC rule action level is actually slightly less stringent than the leak definition in the new source MACT requirements. Furthermore, the 50 ppbw threshold only triggers calculations of emissions, and not necessarily corrective action. Therefore, we disagree with commenters that suggest the HRVOC rule requirements are more stringent than the new or existing MACT floor requirements we established.
In our supplemental proposal, we specifically looked at lowering the leak definition for existing sources from 6.2 ppmv to 3.1 ppmv as part of our beyondthefloor analysis, and determined that this was not costeffective. Incrementally reducing the leak definition to 2 ppmv would be even less costeffective than the option we evaluated. Furthermore, it would result in negligible additional emissions reductions, and it is very near the limit of detection of the El Paso Method. Therefore, we reject the option of setting the leak definition at 2 ppmv for new or existing sources because it is not costeffective.
The commenter requesting different leak definitions for different sized cooling towers is essentially asking for less control for small cooling towers (i.e., an effective leak definition greater than 6.2 ppmv) and more control for larger cooling towers (i.e., an effective leak definition less than 6.2 ppmv, and in some cases less than 3.1 ppmv). In our review of permits, we found no basis for subcategorizing the cooling towers by different recirculation rates. In addition, the suggested approach is inconsistent with the MACT floor requirements we identified for heat exchange systems.
We also disagree with the comments that claim we did not consider the HRVOC rule in our decisionmaking process. We found that most cooling towers that are subject to the HRVOC rule are associated with ethylene production units, and not refinery process units. As we specifically collected recent permit requirements for Texas refineries, to the extent there might be refinery cooling towers subject to the HRVOC rule, those requirements were considered in the development of the MACT floor. As explained above, we also disagree with the commenter's characterization of the stringency of the HRVOC rule in comparison with the new and existing MACT floors.
Our analysis indicated that repair provisions were more important in reducing heat exchange system emissions than using continuous monitoring. Contrary to the commenter's supposition, there are no repair schedules within the HRVOC cooling tower requirements. The commenter actually referenced the repair provisions for fugitive process equipment leaks (valves and pumps), which are not applicable to cooling towers. In the HRVOC rule, the action level is not a leak definition; rather, the leak definition is used to trigger more frequent monitoring for emission estimation and not specific repair requirements. In the HRVOC rules, facilities with cooling towers must meet an annual and an hourly sitewide HRVOC emissions cap. The hourly cap is quite high, and would not require any heat exchanger leaks to be repaired; the annual cap would tend to drive heat exchanger repairs. A mediumsized 30,000 gallon per minute cooling tower with a leak of 1,000 ppbw total VOC containing 20 percent HRVOC (as defined in the Texas rule) would have to repair within 45 days under the MACT floor requirements of this rule, but would not necessarily have to repair in 45 days to comply with the HRVOC rule, which sets a sitewide cap of 10 ton/yr (45 days of emissions would release 1.6 tons of HRVOC, under this scenario).
While different scenarios can be devised, the stringency of the Texas HRVOC rule is not as easy to categorize as the commenters suggest, and it could result in less emission reductions than the proposed new or existing source MACT floors.
Contrary to the commenter's assertion, we also reviewed and evaluated the permit requirements for the cited California refinery, and the permit was included in the docket. The permit, dated April 17, 2008, included a provision for a continuous monitor to be installed at a future date, to be determined, and the planned monitor was not being used at the time of our review. Additionally, based on the cooling tower's recirculation rate and the permitted VOC daily emission rate, the apparent action level (also not yet determined) is likely to be much higher than the leak definition for existing source MACT floors. In the cooling tower memorandum, we only summarized the information from the topranked cooling towers; the cooling tower at this California refinery was not included in the memorandum because, based on actual permit conditions, this cooling tower is not among the top performing 12 percent of cooling towers.
While continuous monitoring was not used by the topperforming cooling towers, and, therefore, is not part of the floor requirements, we did evaluate requiring continuous monitoring in our beyondthefloor analysis. However, the costeffectiveness of this option exceeded half a million dollars per ton of HAP reduced, and, therefore, we did not require continuous monitoring as the standard. Rather, we adopted the floor as the MACT standard.
[[Page 55675]]
Comment: One commenter noted that the proposed recordkeeping and reporting requirements for heat exchange systems are unnecessarily burdensome, go far beyond the requirements for the MACT floor, and should be revised. For the Notice of Compliance Status, the commenter noted that ``heat exchange systems'' are an artifact of the regulation, do not normally have specific names, and will change from time to time, so the requirement to identify the heat exchange systems that are subject to the requirements of this subpart should be changed to a list of cooling towers that serve any heat exchange system or systems in organic HAP service. For periodic reports, the commenter stated that: (1) The number of heat exchange systems in HAP service will change over time, so the requirement to report that number should be deleted; (2) the requirement to report the number of heat exchange systems in HAP service found to be leaking should be changed to a request to identify exchangers found to be leaking; (3) the requirement to report the number of leaks in Sec. 63.655(g)(9)(iii) duplicates the requirement in Sec. 63.655(g)(9)(ii); (4) Sec. 63.655(g)(9)(iii) should not require the reporting of measurements below the leak definition and should only ask for a summary of the leaks identified during the reporting period; (5) each 6month period will include a lot of leaks, so there is no need to report the date of every leak (a record should be sufficient); (6) Sec. 63.655(g)(9)(v) should be revised to reflect all delays and to address situations when a leak is detected in one reporting period and repaired in the next; and (7) reporting the estimate of VOC emissions for delay of repair should only be required when the delay of repair option was invoked. For recordkeeping, the commenter stated that: (1) Calculating the requested information for each heat exchanger in a refinery will take an estimated 40 hours per refinery and must be repeated every year; these burdens were not included in the information collection request (ICR) burden estimate and do not add value for exchangers that will not be monitored due to low HAP content, that do not contact HAP, or would not leak into the cooling water; (2) although sources will need a record of which heat exchange systems include exchangers in organic HAP service to comply with the monitoring requirements, identification of all heat exchangers is not necessary; and (3) the information requested in Sec. 63.655(i)(4)(iii)(E) is sometimes available for whole cooling towers but not readily available for heat exchange exit lines or cooling tower return lines. The commenter stated that temporary heat exchangers and sample coolers should be excluded from these recordkeeping and reporting requirements.
Response: We reviewed the recordkeeping and reporting requirements
identified by the commenter. We do not see how the heat exchange system
will be as variable as the commenter suggested. We have revised the
definition of heat exchange system to clarify our intent. We also: (1)
Amended Sec. 63.655(g)(9)(v) to more clearly indicate that all delayed
repairs must be included and that delays may occur across reporting periods; (2) amended the reporting requirements in Sec.
63.655(g)(9)(vi) to clarify that leak emission estimates are only
required for an actual delay of repair; and (3) clarified in Sec.
63.655(g)(9)(vi) that the flow rate is for the location where the
monitoring occurs. It is anticipated that facilities will monitor at
locations where the flow rate is known based on pump curves, heat
balance calculations, or other engineering methods. A continuous flow
monitor is not required, but a flow rate at the monitoring location is
needed to assess the potential mass emissions associated with a leak.
For the other comments, we find that the recordkeeping and reporting
requirements are needed to document compliance with the rule.
Specifically, identifying heat exchangers and heat exchange systems
that are in organic HAP service, maintaining monitoring results, and
reporting the date a leak is identified and repaired is essential for demonstrating compliance with the monitoring requirements.
2. Applicability Issues
Comment: One commenter supported changing the affected source from ``cooling towers'' to ``heat exchange systems,'' noting that it allows the facilities flexibility in monthly monitoring, leak tracking, and determining best sampling locations. Other commenters stated that Refinery MACT 1 should only apply to heat exchange systems that are part of cooling tower systems and should not apply to oncethrough cooling water systems. The commenters suggested that the supporting documentation indicates that only cooling tower heat exchange systems were evaluated, and, if EPA wants to finalize requirements for once through cooling water systems, the requirements must be properly evaluated and the analyses provided for comment. One commenter stated that the emissions from oncethrough cooling systems are fundamentally different than systems with cooling towers since oncethrough systems do not have the air contact and stripping properties of cooling towers, and, as a result, a cost analysis of the two systems would show considerably different costs. The commenter also noted that the monitoring and repair techniques employed for the oncethrough systems are different than the monitoring for cooling tower systems, and these techniques should be evaluated for best demonstrated control technology (BDT) if oncethrough cooling systems are included in the rule. One commenter noted that, as proposed, the heat exchange system requirements apply to systems where the pressure gradient would not allow leakage into the cooling water. The commenter noted that these systems do not need monitoring, and a pressure gradient threshold of 35 kilopascals (kPa) should be included in the definition of ``heat exchange system'' to exempt these types of systems from Refinery MACT 1. Finally, the commenter stated that including the term ``cooling tower'' in the definition of ``heat exchange system'' could lead to confusion over the monitoring location requirements.
Response: EPA has developed MACT standards, such as the Hazardous Organic NESHAP (HON) and Ethylene MACT, for heat exchange systems, and these standards include oncethrough cooling water systems. Generally, the HON and Ethylene MACT standards allow alternative surrogate means of compliance that are equivalent to those standards. We considered and rejected these alternatives in the development of the requirements that we proposed for heat exchange systems and that we are now finalizing because the HON and Ethylene MACT standards are less stringent than our floor. We are not aware of any means of surrogate monitoring that would achieve identification of leaks equivalent to the floor level of monitoring required for refinery heat exchange systems.
We believe that control of oncethrough heat exchanger cooling
systems is appropriate for several reasons, as outlined below. First,
emissions of volatile HAP such as benzene occur readily from open water
sources, which is why the Benzene Waste Operations NESHAP and the
Refinery MACT 1 wastewater provisions require wastewater streams with
benzene (as a surrogate for volatile HAP) to be covered and controlled
until an appropriate treatment process is used to recover or destroy
the benzene. While the stripping process may not be as fast as in a cooling tower, the oncethrough cooling
[[Page 55676]]
water will have a much longer exposure to the atmosphere than a system
with a cooling tower. Thus, while the emissions may occur over a longer
time period (over a larger area), all available scientific evidence and
fate modeling studies of open water systems leads us to conclude that
essentially all volatile HAP will be released into the atmosphere. As
such, we see no reason why HAP leaks from heat exchange systems into
oncethrough cooling water should be treated any differently than HAP leaks from heat exchange systems that have cooling towers.
Second, in conducting the MACT floor analysis for heat exchange
systems presented in the supplemental proposal, we assumed that once
through cooling waters were included and that emissions from the once
through systems would be similar to those with recirculation of cooling
waters. In reviewing the permits that formed the basis of the MACT
floor analysis, we found that the majority did not indicate whether the
system was oncethrough or recirculating. However, we note that some
permits included text for monitoring of ``cooling towers'' and
``cooling tower water'' and some specified monitoring for ``heat
exchanger system cooling water.'' The latter permits would appear to
include oncethrough systems. Based on review of multiple references,
the use of oncethrough cooling water in the petroleum refinery
industry has been declining over the last 40 years, and is now a very
small subset of the heat exchanger water systems. One reference
indicated that a sample of facilities surveyed back in 1967 showed that
only 5 percent of petroleum refineries were still using oncethrough
cooling.\3\ No more recent data could be found on how many refineries
use oncethrough systems. A more recent study on oncethrough cooling
systems for cogeneration facilities indicated that approximately 11
percent of nonutility plants that cogenerated power use oncethrough
cooling; the 123 nonutility facilities included pulp and paper,
chemical, iron and steel, aluminum, and petroleum refining
industries.\4\ Of the 123 facilities in the survey, four were confirmed
petroleum refineries and three of these four sources provided a
response to the survey. None of the three reported that oncethrough cooling systems were used.
\3\ Gibbons, DC. The Economic Value of Water. Published by Resources for the Future. 1986.
\4\ Veil, J., M. Pruder, D. Littleton, and D. Moses. ``Cooling Water Use Patterns at U.S. Nonutility Electric Generating
Facilities.'' Environmental Science and Policy. 2000.
Hypothetically, if we assumed that there were additional once through cooling systems that were not included in our MACT floor analysis, we could assume that approximately 5 to 11 percent of the total cooling systems were oncethrough. The original number of cooling tower systems included in the MACT floor analysis was 520. If we assume that 5 to 11 percent of the cooling systems are oncethrough systems, then the total hypothetical number of cooling systems could range from 547 to 584 cooling systems. The MACT floor for these cooling systems would be based on the average emissions limitations achieved by the top 12 percent of cooling systems; the 6th percentile would be represented by the 33rd and the 35th cooling systems, respectively, for the hypothetical total number of cooling systems estimated to be 547 and 584. There would be no change in the MACT floor for existing sources for this hypothetical case. The MACT floor would be identical to the requirements in the supplemental proposal, i.e., the 33rd and 35th ranked cooling systems have requirements to implement corrective action and heat exchange leak repairs when the strippable total VOC concentration in stripped air exceeds 6.2 ppmv. The owner or operator must identify the leaking heat exchanger, and repair at the earliest opportunity and no later than the next scheduled shutdown.
To the extent the commenters are suggesting that oncethrough systems should be treated as a separate subcategory, they have provided no information to support that subcategorization is appropriate.
We agree with the commenter and have clarified in Sec. 63.654(b)(1) that the requirements do not apply to heat exchange systems where the minimum waterside pressure is 35 kPa greater than the maximum processside pressure. We have also revised the definition of ``heat exchange system'' to identify the equipment that is included for closedloop recirculation systems (systems with cooling towers), to identify the equipment that is included in the oncethrough systems, and to clarify that oncethrough systems are also regulated. Furthermore, definitions are provided for ``cooling tower return line'' and ``heat exchanger exit line'' to clarify the appropriate sampling locations. Sampling at either location is allowed; for oncethrough cooling systems, sampling is allowed at an aggregated location as long as it is before exposure to the atmosphere. To clarify this requirement, we have modified the definition of ``heat exchange exit line'' to be ``the cooling water line from the exit of one or more heat exchangers (where cooling water leaves the heat exchangers) to either the entrance of the cooling tower return line or prior to exposure to the atmosphere, whichever occurs first.''
3. Compliance Schedule for Heat Exchange Systems
Comment: Several commenters supported the originally proposed compliance date of 3 years and 90 days. One commenter noted that the reference to 90 days in CAA section 112(f)(4) has been misread by some to limit compliance time, but since it is expected that installation of controls necessitates a longer time to comply, the waiver provisions should only be considered if EPA set a compliance deadline less than 3 years. Some commenters noted that 18 months should be sufficient for all new requirements, as industry is already familiar with many of the processes to be controlled and are already regulating these emissions.
Several commenters addressed the compliance dates relative to the supplemental proposal. For new sources, commenters noted that these requirements will be promulgated only 2 months after they were proposed in the supplemental proposal, which is inadequate time in which to have monitors purchased and operating. The commenters asserted that EPA should provide 1 year for new sources to comply with the standards.
Commenters specifically noted that although many Texas refiners are
currently familiar with the monitoring methods required for heat
exchange systems, it took years for them to gain that familiarity, and
it will take time for other refiners to learn to perform the methods
efficiently. One commenter noted that when monitoring begins, there
will be an initial period in which multiple repairs are necessary, some
of which may require shutdowns. The commenters recommended that EPA
provide the full 3 years provided by the CAA for compliance with heat
exchange system requirements; this additional time would allow refiners
to become familiar with the monitoring method and to complete initial
repairs during already scheduled shutdowns and turnarounds. Conversely,
several commenters stated that the cooling tower standards should be
implemented in 1 year rather than progressively over 3 years as
proposed in the supplemental proposal. Another commenter stated that
the 18month compliance schedule for heat exchange systems in the supplemental proposal is preferable to
[[Page 55677]]
the 3year (and 90 days) compliance schedule in the original proposal.
Response: As an initial matter, we note that the originally proposed compliance schedule (i.e., 3 years and 90 days) should not have included the additional 90 days. Section 112(i)(3) of the CAA provides that existing sources must comply within ``3 years after the effective date'' of the standard. With respect to the 18month compliance timeframe specified in our supplemental proposal, we agree that the commenters have made valid points supporting adoption of a 3 year compliance period instead. The comments that many refineries do not have experience with the TCEQ El Paso Method is supported by our review of cooling tower requirements for different States. We believe that some sources will need up to the full 3 years allowed under CAA section 112(i)(3) based on the estimated length of time required for refiners to survey the heat exchangers, identify those in organic HAP service, install the necessary sampling ports, purchase the Modified El Paso sampling system, familiarize themselves with the test method, and provide training to their employees. In addition, refiners will need to take steps to be prepared to repair leaking heat exchange systems. This includes performing initial sampling to identify heat exchangers that are prone to leakage or are in critical service, identify means to isolate or repair heat exchangers online, and to order and stock necessary equipment and spare parts.
With respect to new source requirements, the CAA specifies that such sources must comply upon startup or the date of publication of the final rule, whichever is later. We note that, based on the definition of an affected source in the Refinery MACT 1 rule, a construction project significant enough to trigger the new source provisions is likely to take years to complete, and that any source undertaking such project has been on notice since our initial proposal that cooling tower monitoring (or heat exchange system monitoring) would be required.
4. Delay of Repair Provisions
Comment: Commenters noted that the new source delay of repair standards are based on cooling towers that are not yet operational, so those permit conditions are not ``achieved in practice.'' The commenters argued that it takes time after startup of new facilities to determine if new, previously untested requirements are achievable or whether permit modifications are needed; it is also unknown if Texas will allow deviations from permit conditions and under what conditions for heat exchange system repairs. The commenters stated that the new source delay of repair standards must instead be based on ``Repair and Delay 2'' as described in Table 1 of EPA's supporting memorandum (which the commenter thought were the requirements for the existing source floor).
One commenter supported the 45day repair allowance and delay of repair allowances. Another commenter stated that the maximum delay of repair should be 60 days because refineries already have 18 months to comply. Some commenters expressed concern that EPA proposed to disallow delay of repair for leaks above 62 ppmv after 3 years and noted that EPA has not demonstrated the rationale for removing that allowance. One commenter stated that EPA needs to address the situation in which multiple small leaks occur at multiple heat exchangers and the cumulative effect at the cooling tower return line is a leak above 62 ppmv. The commenters stated that unplanned shutdowns are expensive and disruptive, but would be necessary when repair is infeasible without a shutdown. One commenter requested that EPA allow owners and operators to request delay of repair on a casebycase basis when justified.
Response: The supplemental proposed MACT floor for both new and existing sources is repair within 45 days for leaks of 62 ppmv or greater. In establishing the floor, we found that the no delay of repairs requirement for large leaks has been implemented and required for 35 cooling towers at numerous facilities. Also, both the topranked and 6th percentile cooling tower had identical requirements excluding large leaks from delay of repair. As such, this requirement has been implemented and has been adequately demonstrated and it establishes the minimum floor requirement. In the supplemental proposal, we proposed to allow delay of repair for large leaks for the 18 month phasein of the repair requirements, which correspond to the ``Repair and Delay 2'' provisions cited by the commenter. However, we have concluded that these temporary delay of repair provisions were not equivalent to the requirements for the MACT floor for existing heat exchange systems, which is why they were only temporary provisions in the supplemental proposal. Additionally, the 3year compliance timeframe in the final rule will allow facilities sufficient time to resolve these initial problems. As discussed previously, we are now implementing all heat exchange system requirements for existing sources on the same 3year schedule. Upon implementation of the required monitoring provisions, it is anticipated that leaks will be identified well before they become large. Thus, while delay of repairs are allowed for small leaks, it is the refinery owner or operator's responsibility to order necessary parts and schedule a repair before the leak exceeds the 62 ppmv threshold. Negligence on the part of the owner or operator regarding this responsibility is not a reasonable justification for providing delay of repair provisions for large leaks. Consistent with the requirements that apply to the units which provided the basis for the MACT floor, any leak greater than 62 ppmv that is not repaired in the timelines provided in the rule is a deviation of the standard and subject to enforcement actions at the discretion of the Agency or permitting authority.
5. Monitoring Alternatives
Comment: Commenters noted that the concentration of heavy organic
HAP and water soluble HAP can build up in recirculating cooling tower
systems, and since the El Paso Method involves more vigorous stripping
than occurs in a cooling tower, monitoring might falsely indicate a
leak. The commenters suggested that, as an alternative, sources should
be allowed to use methods they are presently using, including testing
the inlet water to a heat exchange system and using the difference
between the outlet and the inlet to determine if the leak definition is
exceeded. One commenter noted that if oncethrough cooling systems
continue to be considered affected facilities by EPA, it is important
for the requirements to consider the baseline of HAP (or surrogate VOC)
emissions in the inlet to the system so that facilities are only
responsible for assessing any ``increase'' in the pollutant attributed
to the operating facility, not pollutants in the water basin upstream
of the facility. Another commenter requested that EPA allow owners or
operators to demonstrate that another monitoring method such as a
continuous emission monitoring system or parameter monitoring is
equivalent to the monitoring methods specified for heat exchange
systems. One commenter requested that EPA continue to allow the method
originally proposed as well as a relatively new analytical method for
early detection developed by Baker Petrolite. Another commenter stated
that the El Paso Method measures VOC in the air, and EPA should allow
any monitoring method that has adequate sensitivity to measure 80 ppbw of
[[Page 55678]]
strippable VOC in the water or for a surrogate that can be correlated
to strippable VOC and can be measured at a level that would indicate a
leak of 80 ppbw of strippable VOC in the water for a particular heat
exchange system. This monitoring flexibility would be helpful to
confirm El Paso results as well as more efficient for sources that are
required to conduct other types of monitoring by their State or local
agency or for compliance with another Federal regulation (such as the HON).
Response: We acknowledge that some refineries have specific monitoring systems inplace and that the use of these monitoring systems would ease the burden on the refinery owner or operator. However, we are not aware of any practical alternatives that we can specify that provide an equivalent measure of strippable organics. Nor have any of the commenters provided evidence that a specific alternative method would result in an equivalent measure. For example, we have reviewed the ``method for early detection developed by Baker Petrolite'' and found that the detection level for most individual compounds is much higher than the total strippable VOC concentrations that define a leak for the MACT floor facility. That is, this method would not be able to identify small to mediumsized leaks that would be identified and would be required to be fixed by the MACT requirements for heat exchange systems.
Although we expect the El Paso column to mimic the stripping that occurs in the cooling tower, the amount of stripping that occurs in the cooling tower is dependent on the design and operation of the cooling tower. Moreover, the purpose for the use of the El Paso Method is to detect leaks in heat exchange systems, not to estimate emissions. Consequently, we do not believe that analytical methods based on the measurement of single constituents or that employ inlet/outlet cooling tower water sampling are equivalent to the El Paso Method for determining strippable VOC. That is, these alternative methods would not result in the same corrective action thresholds as the prescribed monitoring technique.
The commenters have provided no evidence that a buildup of heavy organics would cause a heat exchange system to exceed a leak definition of 6.2 ppmv total strippable VOC, nor have they provided compelling evidence that such a leak would not result in any air emissions. While we agree that the relative stripping efficiency of a given cooling tower will not necessarily match the stripping efficiency of the El Paso stripping column, it is unreasonable to conclude that the cooling tower will have no HAP emissions. Furthermore, the majority of HAP included in Table 1 are volatile. Thus, for a heat exchange system that is ``in HAP service,'' we believe it is appropriate to initiate corrective action if the leak threshold is exceeded because that corrective action will result in reduced HAP emissions.
As stated previously, the goal of the heat exchange system provisions is to identify and fix leaks at the heat exchanger to reduce subsequent emissions of HAP. For oncethrough cooling systems, we believe it is unlikely that the strippable organics concentration in the inlet water would exceed the leak threshold. Further, the commenters have provided no evidence that the fresh water feed for a oncethrough heat exchange system could contain enough strippable organics to cause a heat exchange system to exceed a leak definition of 6.2 ppmv total strippable VOC. Therefore, we have not provided any alternative leak detection procedure for oncethrough heat exchangers.
Comment: Commenters supported allowing the facility to demonstrate that a leak is not in a heat exchanger that is in HAP service. One commenter stated that if VOC testing indicates a leak in a heat exchange system, the facility should be allowed to speciate the compounds in the leak to determine if the leak is a HAP leak. Another commenter agreed, noting that proposed Sec. 63.654(e) requires monitoring of every individual exchanger in organic HAP service in a heat exchange system in order to prove that the leak is not from an exchanger in organic HAP service. The commenter stated that this requirement is very costly and recommended three alternatives: (1) The owner or operator should be allowed to determine the species in the process or processes served by the cooling tower to determine if the process is in HAP service; (2) the owner or operator should be allowed to speciate the sample from the cooling tower return line to determine the leaking heat exchanger; and (3) the owner or operator should be allowed to sample groups of heat exchangers rather than each individual heat exchanger.
One commenter noted that the supplemental proposal appears to only allow sampling at the outlet of each heat exchanger or at the inlet to a cooling tower, but it is often preferred to sample at branch points in cooling tower return piping for several reasons: (1) Only a particular branch has exchangers in HAP service; (2) it is easier to identify the source of any leak that does occur; or (3) a particular cooling tower is shared among administrative units and compliance is more readily achieved if each unit is responsible for its own heat exchangers. The commenter also noted that the language is inconsistent with the definition of ``heat exchange system,'' which can be any number of exchangers, not just one exchanger or all exchangers in a particular cooling water loop. The commenter suggested revisions to the definition of ``cooling tower return line'' to clarify the requirement.
Response: The purpose for the rule is to find and fix leaks for heat exchange systems in organic HAP service. If a leak is detected at a cooling tower return line or in a oncethrough system, the owner/ operator can find and fix the leak by any means possible, including the means specified by the commenters. If, however, the owner/operator does not want to fix the leak because they believe that the leak is caused by heat exchangers that are not in organic HAP service, the only way to definitively prove that is to test the individual or groups of heat exchangers in organic HAP service that make up the system in which a leak has been detected.
The Texas permit data and TCEQ El Paso Method is based on strippable VOC. We found that this is an appropriate surrogate for HAP emissions for cooling towers that are in HAP service. A refinery may use speciation of the El Paso column stripping air or other methods at their discretion to determine the location of the leak. However, we cannot provide, based on the MACT floor requirements, an alternative action level that defines a HAP leak as opposed to a VOC leak, as the commenter proposes.
We have made minor adjustments to the final standards to allow our
intended outcome of alternative 3, as described by the commenter.
Specifically, we have clarified the definition of heat exchanger exit
line to include water lines from ``one or more heat exchangers.'' This
clarification is intended to allow monitoring using the Modified El
Paso Method from each heat exchanger or group of heat exchangers in
organic HAP service upstream of the cooling tower return line. For
example, if three process units are served by one heat exchange system
and multiple heat exchangers are grouped by process unit and the three
return lines combine before the main cooling tower return line, then
the owner or operator may choose to measure each of the three return
lines associated with a process unit in organic HAP service. If monitoring at those points results in concentrations less
[[Page 55679]]
than the leak definition, then no repair is necessary.
6. Impact Estimates for Cooling Towers
Comment: Several commenters argued that EPA's estimates of baseline emissions were based on faulty and unsupported premises. One c
FOR FURTHER INFORMATION CONTACT
Mr. Robert Lucas, Office of Air
Quality Planning and Standards, Sector Policies and Programs Division,
Coatings and Chemicals Group (E14301), Environmental Protection
Agency, Research Triangle Park, North Carolina 27711, telephone number (919) 5410884; fax number (919) 5410246; email address:
lucas.bob@epa.gov.