Table 10 to Subpart DDDDD of Part 63   Applicability of General Provisions to Subpart DDDDD As stated in § 63.7565, you must comply with the applicable General Provisions according to the following:

Citation Subject Brief Description Comments § 63.1 Applicability Initial Applicability Determination; Applicability After Standard Established; Permit Requirements; Extensions, Notifications Yes.

§ 63.2 Definitions Definitions for part 63 standards Yes.

§ 63.3 Units and Abbreviations Units and abbreviations for part 63 standards Yes.

§ 63.4 Prohibited Activities Prohibited Activities; Compliance date; Circumvention, Severability Yes.

§ 63.5 Construction/ Rec onstruction Applicability; applications; approvals Yes.

§ 63.6( a) Applicability GP apply unless compliance extension AND GP apply to area sources that become major Yes.

§ 63.6( b)( 1)( 4) Compliance Dates for New and Reconstructed sources Standards apply at effective date; 3 years after effective date; upon startup; 10 years after construction or reconstruction commences for 112( f) Yes.

§ 63.6( b)( 5) Notification Must notify if commenced construction or reconstruction after proposal Yes.

§ 63.6( b)( 6) [ Reserved] Citation Subject Brief Description Comments § 63.6( b)( 7) Compliance Dates for New and Reconstructed Area Sources That Become Major Area sources that become major must comply with major source standards immediately upon becoming major, regardless of whether required to comply when they were an area source Yes.

§ 63.6( c)( 1)( 2) Compliance Dates for Existing Sources Comply according to date in subpart, which must be no later than 3 years after effective date AND For 112( f) standards, comply within 90 days of effective date unless compliance extension Yes.

§ 63.6( c)( 3)( 4) [ Reserved]

§ 63.6( c)( 5) Compliance Dates for Existing Area Sources That Become Major Area sources that become major must comply with major source standards by date indicated in subpart or by equivalent time period ( for example, 3 years) Yes.

§ 63.6( d) [ Reserved]

§ 63.6( e)( 1)( 2) Operation & Maintenance Operate to minimize emissions at all times AND Correct malfunctions as soon as practicable AND Operation and maintenance requirements independently enforceable information Administrator will use to determine if operation and maintenance requirements were met Yes.

§ 63.6( e)( 3) Startup, Shutdown, and Malfunction Plan ( SSMP) Requirement for SSM and startup, shutdown, malfunction plan Content of SSMP Yes. Citation Subject Brief Description Comments § 63.6( f)( 1) Compliance Except During SSM Comply with emission standards at all times except during SSM Yes.

§ 63.6( f)( 2)( 3) Methods for Determining Compliance Compliance based on performance test, operation and maintenance plans, records, inspection Yes.

§ 63.6( g)( 1)( 3) Alternative Standard Procedures for getting an alternative standard Yes.

§ 63.6( h)( 1) Compliance with Opacity/ VE Standards Comply with opacity/ VE emission limitations at all times except during SSM Yes.

§ 63.6( h)( 2)( i) Determining Compliance with Opacity/ Visible Emission ( VE) Standards If standard does not state test method, use Method 9 for opacity and Method 22 for VE No.

§ 63.6( h)( 2)( ii) [ Reserved]

§ 63.6( h)( 2)( iii) Using Previous Tests to Demonstrate Compliance with Opacity/ VE Standards Criteria for when previous opacity/ VE testing can be used to show compliance with this rule Yes.

§ 63.6( h)( 3) [ Reserved]

§ 63.6( h)( 4) Notification of Opacity/ VE Observation Date Notify Administrator of anticipated date of observation No.

§ 63.6( h)( 5)( i), ( iii)( v) Conducting Opacity/ VE Observations Dates and Schedule for conducting opacity/ VE observations No.

§ 63.6( h)( 5)( ii) Opacity Test Duration and Averaging Times Must have at least 3 hours of observation with thirty, 6 minute averages No.

§ 63.6( h)( 6) Records of Conditions During Opacity/ VE observations Keep records available and allow Administrator to inspect No. Citation Subject Brief Description Comments § 63.6( h)( 7)( i) Report continuous opacity monitoring system Monitoring Data from Performance Test Submit continuous opacity monitoring system data with other performance test data Yes.

§ 63.6( h)( 7)( ii) Using continuous opacity monitoring system instead of Method 9 Can submit continuous opacity monitoring system data instead of Method 9 results even if rule requires Method 9, but must notify Administrator before performance test No.

§ 63.6( h)( 7) ( iii) Averaging time for continuous opacity monitoring system during performance test To determine compliance, must reduce continuous opacity monitoring system data to 6 minute averages Yes.

§ 63.6( h)( 7)( iv) Continuous opacity monitoring system requirements Demonstrate that continuous opacity monitoring system performance evaluations are conducted according to § § 63.8( e), continuous opacity monitoring system are properly maintained and operated according to 63.8( c) and data quality as § 63.8( d) Yes.

§ 63.6( h)( 7)( v) Determining Compliance with Opacity/ VE Standards Continuous opacity monitoring system is probative but not conclusive evidence of compliance with opacity standard, even if Method 9 observation shows otherwise. Requirements for continuous opacity monitoring system to be probative evidence   proper maintenance, meeting PS 1, and data have not been altered Yes. Citation Subject Brief Description Comments § 63.6( h)( 8) Determining Compliance with Opacity/ VE Standards Administrator will use all continuous opacity monitoring system, Method 9, and Method 22 results, as well as information about operation and maintenance to determine compliance Yes.

§ 63.6( h)( 9) Adjusted Opacity Standard Procedures for Administrator to adjust an opacity standard Yes.

§ 63.6( i)( 1)( 14) Compliance Extension Procedures and criteria for Administrator to grant compliance extension Yes.

§ 63.6( j) Presidential Compliance Exemption President may exempt source category from requirement to comply with rule Yes.

§ 63.7( a)( 1) Performance Test Dates Dates for Conducting Initial Performance Testing and Other Compliance Demonstrations Yes.

§ 63.7( a)( 2)( i) Performance Test Dates New source with initial startup date before effective date has 180 days after effective date to demonstrate compliance Yes.

§ 63.7( a)( 2)( ii) Performance Test Dates New source with initial startup date after effective date has 180 days after initial startup date to demonstrate compliance Yes.

Existing source subject to standard established pursuant to 112( d) has 180 days after compliance date to demonstrate compliance AND § 63.7( a)( 2)( iii) Performance Test Dates Existing source with startup date after effective date has 180 days after startup to demonstrate compliance No.

Yes.

§ 63.7( a)( 2)( iv) Performance Test Dates Existing source subject to standard established pursuant to 112( f) has 180 days after compliance date to demonstrate compliance No. Citation Subject Brief Description Comments § 63.7( a)( 2)( v) Performance Test Dates Existing source that applied for extension of compliance has 180 days after termination date of extension to demonstrate compliance Yes.

§ 63.7( a)( 2)( vi) Performance Test Dates New source subject to standard established pursuant to 112( f) that commenced construction after proposal date of 112( d) standard but before proposal date of 112( f) standard, has 180 days after compliance date to demonstrate compliance No.

§ 63.7( a)( 2)( viiviii [ Reserved]

§ 63.7( a)( 2)( ix) Performance Test Dates New source that commenced construction between proposal and promulgation dates, when promulgated standard is more stringent than proposed standard, has 180 days after effective date or 180 days after startup of source, whichever is later, to demonstrate compliance AND If source initially demonstrates compliance with less stringent proposed standard, it has 3 years and 180 days after the effective date of the standard or 180 days after startup of source, whichever is later, to demonstrate compliance with promulgated standard Yes.

No.

§ 63.7( a)( 3) Section 114 Authority Administrator may require a performance test under CAA Section 114 at any time Yes.

§ 63.7( b)( 1) Notification of Performance Test Must notify Administrator 60 days before the test Yes. Citation Subject Brief Description Comments § 63.7( b)( 2) Notification of Rescheduling If rescheduling a performance test is necessary, must notify Administrator 5 days before scheduled date of rescheduled date Yes.

§ 63.7( c) Quality Assurance/ Test Plan Requirement to submit sitespecific test plan 60 days before the test or on date Administrator agrees with:

Test plan approval procedures AND Performance audit requirements AND Internal and External QA procedures for testing Yes.

§ 63.7( d) Testing Facilities Requirements for testing facilities Yes.

Performance tests must be conducted under representative conditions No.

AND Cannot conduct performance tests during SSM. Yes.

AND Not a deviation to exceed standard during SSM Yes.

AND § 63.7( e)( 1) Conditions for Conducting Performance Tests Upon request of Administrator, make available records necessary to determine conditions of performance tests Yes.

§ 63.7( e)( 2) Conditions for Conducting Performance Tests Must conduct according to rule and EPA test methods unless Administrator approves alternative Yes. Citation Subject Brief Description Comments § 63.7( e)( 3) Test Run Duration Must have three separate test runs AND Compliance is based on arithmetic mean of three runs AND Conditions when data from an additional test run can be used Yes.

§ 63.7( f) Alternative Test Method Procedures by which Administrator can grant approval to use an alternative test method Yes.

§ 63.7( g) Performance Test Data Analysis Must include raw data in performance test report AND Must submit performance test data 60 days after end of test with the Notification of Compliance Status AND Keep data for 5 years Yes.

§ 63.7( h) Waiver of Tests Procedures for Administrator to waive performance test Yes.

§ 63.8( a)( 1) Applicability of Monitoring Requirements Subject to all monitoring requirements in standard Yes.

§ 63.8( a)( 2) Performance Specifications Performance Specifications in appendix B of part 60 apply Yes.

§ 63.8( a)( 3) [ Reserved]

§ 63.8( a)( 4) Monitoring with Flares Unless your rule says otherwise, the requirements for flares in § 63.11 apply No.

§ 63.8( b)( 1)( i) ( ii) Monitoring Must conduct monitoring according to standard unless Administrator approves alternative Yes. Citation Subject Brief Description Comments § 63.8( b)( 1)( iii) Monitoring Flares not subject to this section unless otherwise specified in relevant standard No.

§ 63.8( b)( 2)( 3) Multiple Effluents and Multiple Monitoring Systems Specific requirements for installing monitoring systems AND Must install on each effluent before it is combined and before it is released to the atmosphere unless Administrator approves otherwise AND If more than one monitoring system on an emission point, must report all monitoring system results, unless one monitoring system is a backup Yes.

§ 63.8( c)( 1) Monitoring System Operation and Maintenance Maintain monitoring system in a manner consistent with good air pollution control practices Yes.

§ 63.8( c)( 1)( i) Routine and Predictable SSM Follow the SSM plan for routine repairs. Keep parts for routine repairs readily available Reporting requirements for SSM when action is described in SSM plan Yes.

§ 63.8( c)( 1)( ii) SSM not in SSMP Reporting requirements for SSM when action is not described in SSM plan Yes. Citation Subject Brief Description Comments § 63.8( c)( 1)( iii) Compliance with Operation and Maintenance Requirements How Administrator determines if source complying with operation and maintenance requirements AND Review of source O& M procedures, records, Manufacturer's instructions, recommendations, and inspection of monitoring system Yes.

§ 63.8( c)( 2)( 3) Monitoring System Installation Must install to get representative emission and parameter measurements AND Must verify operational status before or at performance test Yes.

§ 63.8( c)( 4) Continuous Monitoring System ( CMS) Requirements Continuous monitoring systems must be operating except during breakdown, out of control, repair, maintenance, and high level calibration drifts No.

§ 63.8( c)( 4)( i) Continuous Monitoring System ( CMS) Requirements Continuous opacity monitoring system must have a minimum of one cycle of sampling and analysis for each successive 10 second period and one cycle of data recording for each successive 6 minute period Yes.

§ 63.8( c)( 4)( ii) Continuous Monitoring System ( CMS) Requirements Continuous emissions monitoring system must have a minimum of one cycle of operation for each successive 15 minute period No.

§ 63.8( c)( 7)( 8) Continuous monitoring systems Requirements Out of control periods, including reporting Yes. Citation Subject Brief Description Comments § 63.8( d) Continuous monitoring systems Quality Control Requirements for continuous monitoring systems quality control, including calibration, etc.

AND Must keep quality control plan on record for the life of the affected source. Keep old versions for 5 years after revisions Yes.

§ 63.8( e) Continuous monitoring systems Performance Evaluation Notification, performance evaluation test plan, reports Yes.

§ 63.8( f)( 1)( 5) Alternative Monitoring Method Procedures for Administrator to approve alternative monitoring Yes.

§ 63.8( f)( 6) Alternative to Relative Accuracy Test Procedures for Administrator to approve alternative relative accuracy tests for continuous emissions monitoring system No.

§ 63.8( g)( 1)( 4) Data Reduction Continuous opacity monitoring system 6 minute averages calculated over at least 36 evenly spaced data points AND Continuous emissions monitoring system 1 hour averages computed over at least 4 equally spaced data points Yes.

§ 63.8( g)( 5) Data Reduction Data that cannot be used in computing averages for continuous emissions monitoring system and continuous opacity monitoring system No.

§ 63.9( a) Notification Requirements Applicability and State Delegation Yes. Citation Subject Brief Description Comments § 63.9( b)( 1)( 5) Initial Notifications Submit notification 120 days after effective date AND Notification of intent to construct/ reconstruct AND Notification of commencement of construct/ reconstruct; Notification of startup AND Contents of each Yes.

§ 63.9( c) Request for Compliance Extension Can request if cannot comply by date or if installed BACT/ LAER Yes.

§ 63.9( d) Notification of Special Compliance Requirements for New Source For sources that commence construction between proposal and promulgation and want to comply 3 years after effective date Yes.

§ 63.9( e) Notification of Performance Test Notify Administrator 60 days prior Yes.

§ 63.9( f) Notification of VE/ Opacity Test Notify Administrator 30 days prior Yes.

§ 63.9( g) Additional Notifications When Using Continuous Monitoring Systems Notification of performance evaluation AND Notification using continuous opacity monitoring system data AND Notification that exceeded criterion for relative accuracy Yes. Citation Subject Brief Description Comments § 63.9( h)( 1)( 6) Notification of Compliance Status Contents AND Due 60 days after end of performance test or other compliance demonstration, except for opacity/ VE, which are due 30 days after When to submit to Federal vs. State authority Yes.

§ 63.9( i) Adjustment of Submittal Deadlines Procedures for Administrator to approve change in when notifications must be submitted Yes.

§ 63.9( j) Change in Previous Information Must submit within 15 days after the change Yes.

§ 63.10( a) Recordkeeping/ Re porting Applies to all, unless compliance extension AND When to submit to Federal vs. State authority AND Procedures for owners of more than 1 source Yes.

§ 63.10( b)( 1) Recordkeeping/ Re porting General Requirements AND Keep all records readily available AND Keep for 5 years Yes. Citation Subject Brief Description Comments § 63.10( b)( 2)( i) ( v) Records related to Startup, Shutdown, and Malfunction Occurrence of each of operation ( process equipment)

AND Occurrence of each malfunction of air pollution equipment AND Maintenance on air pollution control equipment AND Actions during startup, shutdown, and malfunction Yes.

§ 63.10( b)( 2)( vi) and ( x xi) Continuous monitoring systems Records Malfunctions, inoperative, out of control AND Calibration checks AND Adjustments, maintenance Yes.

§ 63.10( b)( 2)( vii )( ix) Records Measurements to demonstrate compliance with emission limitations AND Performance test, performance evaluation, and visible emission observation results AND Measurements to determine conditions of performance tests and performance evaluations. Yes.

§ 63.10( b)( 2)( xii ) Records Records when under waiver Yes.

§ 63.10( b)( 2)( xii i) Records Records when using alternative to relative accuracy test Yes. Citation Subject Brief Description Comments § 63.10( b)( 2)( xiv ) Records All documentation supporting Initial Notification and Notification of Compliance Status Yes.

§ 63.10( b)( 3) Records Applicability Determinations Yes.

§ 63.10( c)( 1) ( 6),( 9)( 15) Records Additional Records for continuous monitoring systems Yes.

§ 63.10( c)( 7)( 8) Records Records of excess emissions and parameter monitoring exceedances for continuous monitoring systems No.

§ 63.10( d)( 1) General Reporting Requirements Requirement to report Yes.

§ 63.10( d)( 2) Report of Performance Test Results When to submit to Federal or State authority Yes.

§ 63.10( d)( 3) Reporting Opacity or VE Observations What to report and when Yes.

§ 63.10( d)( 4) Progress Reports Must submit progress reports on schedule if under compliance extension Yes.

§ 63.10( d)( 5) Startup, Shutdown, and Malfunction Reports Contents and submission Yes.

§ 63.10( e)( 1)( 2) Additional continuous monitoring systems Reports Must report results for each CEM on a unit AND Written copy of performance evaluation AND 3 copies of continuous opacity monitoring system performance evaluation Yes.

§ 63.10( e)( 3) Reports Excess Emission Reports No. Citation Subject Brief Description Comments § 63.10( e)( 3)( iiii Reports Schedule for reporting excess emissions and parameter monitor exceedance ( now defined as deviations) No.

§ 63.10( e)( 3)( ivv Excess Emissions Reports Requirement to revert to quarterly submission if there is an excess emissions and parameter monitor exceedance ( now defined as deviations)

AND Provision to request semiannual reporting after compliance for one year AND Submit report by 30th day following end of quarter or calendar half AND If there has not been an exceedance or excess emission ( now defined as deviations), report contents is a statement that there have been no deviations No.

§ 63.10( e)( 3)( ivv Excess Emissions Reports Must submit report containing all of the information in § 63.10( c)( 5 13), § 63.8( c)( 7 8) No.

§ 63.10( e)( 3)( viviii Excess Emissions Report and Summary Report Requirements for reporting excess emissions for continuous monitoring systems ( now called deviations)

Requires all of the information in § 63.10( c)( 5 13), § 63.8( c)( 7 8) No.

§ 63.10( e)( 4) Reporting continuous opacity monitoring system data Must submit continuous opacity monitoring system data with performance test data Yes. Citation Subject Brief Description Comments § 63.10( f) Waiver for Recordkeeping/ Re porting Procedures for Administrator to waive Yes.

§ 63.11 Flares Requirements for flares No.

§ 63.12 Delegation State authority to enforce standards Yes.

§ 63.13 Addresses Addresses where reports, notifications, and requests are sent Yes.

§ 63.14 Incorporation by Reference Test methods incorporated by reference Yes.

§ 63.15 Availability of Information Public and confidential information Yes. Appendix A to Subpart DDDDD   Methodology and Criteria for Demonstrating Eligibility for the Risk Based Compliance Alternatives Specified for the Large Solid Fuel Subcategory 1. Purpose/ Introduction This appendix provides the methodology and criteria for demonstrating that your affected source is eligible for the alternative compliance option for the HCl emission limit and/ or excluding manganese from the total selected metals emission limit. This appendix specifies emissions testing methods that you must use to determine HCl, chlorine, manganese, and other HAP emissions from the affected sources and what parts of the affected source facility must be included in the eligibility demonstration. You must determine if your facility is eligible for the risk based provisions using either a look up table analysis ( based on the look up tables included in this appendix)

or site specific risk assessment performed according to the criteria specified in this appendix. This appendix also specifies how and when you file any eligibility demonstrations for your affected source and how to show that your affected source remains eligible for the risk based compliance alternatives in the future.

2. Who is eligible to demonstrate that they qualify for the risk based compliance alternatives?

Each new, reconstructed, or existing affected source may demonstrate that they are eligible for the risk based provisions. Section 63.7490 of subpart DDDDD defines the affected source and explains which affected sources are new,

existing, or reconstructed.

3. What parts of my facility have to be included in the riskbased eligibility demonstration?

If you are attempting to determine your eligibility for the alternative compliance option for HCl, you must include every appropriate emission point within the affected source facility that emits one or more of the following HAP, which are referred to as respiratory toxicants, in the eligibility demonstration:

Respiratory Toxicants Pollutant CAS Number Chlorine 7782 50 5 Propylene oxide 75 56 9 Styrene oxide 96 09 3 Acrolein 107 02 8 Titanium tetrachloride 7550 45 0 Triethylamine 121 44 8 Bis( 2 ethylhexyl) phthalate 117 81 7 2,4 Toluene diisocyanate 26471 62 5 Acrylic acid 79 10 7 Acrylonitrile 107 13 1 Vinyl acetate 108 05 4 Toluene 108 88 3 Methyl isocyanate 624 83 9 n Hexane 110 54 3 Nickel compounds Antimony compounds Beryllium compounds Hexavalent Chromium compounds If you are attempting to determine your eligibility for the alternative compliance option for manganese, you must include every appropriate emission point within the affected source facility that emits one or more of the following HAP, which are referred to as central nervous system toxicants, in the eligibility demonstration.

Central nervous system toxicants Pollutant CAS Number Dichlorvos 62 73 7 Cresols ( mixed) 1319 77 3 Benzidine 92 87 5 Allyl chloride 107 05 1 Acrylamide 79 06 1 Carbon disulfide 75 15 0 1,1,1 Trichloroethane 71 55 6 Ethylene oxide 75 21 8 Styrene 100 42 5 Tetrachloroethene 127 18 4 Methyl chloride 74 87 3 n Hexane 110 54 3 Xylenes ( mixed) 1330 20 7 Toluene 108 88 3 Cyanide compounds Selenium compounds Mercury compounds Manganese compounds 4. How do I determine HAP emissions from my affected source?

( a) You must conduct HAP emissions tests for every appropriate emission point within the affected source facility that emits HAP according to the requirements in paragraphs ( b)

through ( f) of this section and the methods specified in Table 1 of this appendix. You must test the units at your facility for each of the appropriate pollutants listed in section 3 above. ( b) Periods when emissions tests must be conducted.

( 1) You must not conduct emissions tests during periods of startup, shutdown, or malfunction, as specified in § 63.7( e)( 1).

( 2) You must test under worst case operating conditions as defined in this appendix. You must describe your worst case operating conditions in your performance test report for the process and control systems ( if applicable) and explain why the conditions are worst case.

( c) Number of test runs. You must conduct three separate test runs for each test required in this section, as specified in § 63.7( e)( 3). Each test run must last at least 1 hour.

( d) Sampling locations. Sampling sites must be located at the outlet of the control device and prior to any releases to the atmosphere.

( e) Collection of monitoring data for HAP control devices.

During the emissions test, you must collect operating parameter monitoring system or continuous emissions monitoring system ( CEMS) data at least every 15 minutes during the entire emissions test and establish the site specific operating requirements in Table 2 of subpart DDDDD using data from the monitoring system and the procedures specified in § 63.7530 of subpart DDDDD.

( f) Nondetect data. You may treat emissions of an individual HAP as zero if all of the test runs result in a nondetect measurement and the condition in paragraph ( 1) is met for the manganese test method. Otherwise nondetect data for individual HAP must be treated as one half of the method detection limit.

( 1) For manganese measured using Method 29 in appendix A to 40 CFR part 60, you analyze samples using atomic absorption spectroscopy ( AAS).

( g) You must determine the maximum hourly emission rate for each appropriate emission point according to equation 1.

Where:

MaxHourly = Maximum hourly emissions for Emissions hydrogen chloride,

chlorine, manganese, or other HAP, in units of pounds per hour.

Er = Emission rate ( as calculated according to Table 1 of this appendix) for hydrogen chloride,

chlorine, manganese, or other HAP, in MaxHourlyEmissions ER Hm = × units of pounds per million Btu of heat input.

Hm = Maximum rated heat input capacity of appropriate emission point, in units of million Btu per hour.

5. What are the criteria for determining if my facility is eligible for a risk based alternative compliance option?

( a) Determine the HAP emissions from each appropriate emission point within the affected source facility using the procedures specified in section 4 of this appendix.

( b) Determine if your facility is eligible for either of the risk based alternative compliance options by conducting a chronic noncancer risk assessment for your facility using one of the methods described in either section 6 of this appendix ( look up table analysis) or section 7 of this appendix (

sitespecific risk assessment).

( c) Your facility is eligible for the risk based alternative compliance option for HCl if 1 of the following 2 statements is true:

( 1) The calculated HCl equivalent emissions for your entire facility is below the appropriate value in the look up table;

( 2) Your site specific risk assessment indicates that your total facility maximum respiratory HI is less than 1.0;

( d) Your facility is eligible for the risk based alternative compliance option for manganese if 1 of the following 2 statements is true:

( 1) The calculated manganese equivalent emissions for your entire facility is below the appropriate value in the lookup table;

( 2) Your site specific risk assessment indicates that your total facility maximum central nervous system HI is less than 1.0;

6. How do I conduct a look up table analysis?

You may use look up tables to determine if your facility is eligible for either the alternative compliance option for the HCl emission limit or the alternative compliance option for manganese.

( a) HCl risk based compliance alternative. Determine the total toxicity weighted HCl equivalent emission rate for your facility. Develop the total facility emission rate of HCl by summing the maximum hourly HClL emission rates from all sources within the facility boundary line. Similarly, develop the total facility emission rate for Cl2. Now, develop the totalfacility emission rate for each of the respiratory toxicants emitted by your facility by summing the emissions across all emission points within the facility boundary line except those covered by subpart DDDDD. A toxicity weighted emission rate expressed in HCl equivalents is then calculated according to equation 1 of this appendix.

ERtw =

( ERi x ( RfCHCl/ RfCi))

Eq. 1 where: ERtw is toxicity weighted emission rate ER i is the emission rate of HAP i in lbs/ hr RfCi is the reference concentration of HAP i RfCHCl is the reference concentration of HCl ( RfCs and other appropriate dose response values can be found at http:// www. epa. gov/ ttn/ atw/ toxsource/ summary. html)

Calculated toxicity weighted emission rates will then be compared to the appropriate allowable toxicity weighted emission rate in Table 2 of this appendix. To determine the correct value from the table, a facility wide average value should be used for stack height and the minimum distance between any stack at the facility and the closest boundary of the nearest residential ( or residentially zoned) area should be used for fenceline distance. If one or both of these values do not match the values in the lookup tables then use the next lowest table value. Your facility is eligible for alternative compliance with the HCl emission limit if your toxicity weighted emission rate,

determined using the methods specified in this appendix, does not exceed the appropriate value in Table 2 of this appendix.

( b) Manganese Exclusion. Determine the total toxicityweighted manganese equivalent emission rate for your affected source by summing the maximum hourly manganese emission rates for all sources within the facility boundary line and the maximum hourly emission rates of any additional central nervous system toxicants from all emission points within the facility boundary line except those covered by subpart DDDDD. A toxicityweighted emission rate expressed in manganese equivalents is then calculated according to equation 2 of this appendix.

ERtw =

( ERi x ( RfCMn/ RfCi))

Eq. 2 where: ERtw is toxicity weighted emission rate ER i is the emission rate of HAP i in lbs/ hr RfCi is the reference concentration of HAP i RfCMn is the reference concentration of manganese ( RfCs and other appropriate dose response values can be found at http:// www. epa. gov/ ttn/ atw/ toxsource/ summary. html)

Calculated toxicity weighted emission rates will then be compared to the appropriate allowable toxicity weighted emission rate in the table. To determine the correct value from the table, a facility wide average value should be used for stack height and the minimum distance between any stack at the facility and the closest boundary of the nearest residential ( or residentially zoned) area should be used for fenceline distance. If one or both of these values do not match the values in the lookup tables then use the next lowest table value. Your facility may exclude manganese when demonstrating compliance with the total selected metals emission limit if your toxicity weighted emission rate, determined using the methods specified in this appendix, does not exceed the values specified in Table 3 of this appendix. 7. How do I conduct a site specific risk assessment?

If you fail to demonstrate that your facility is low risk using the lookup table approach, you may choose to perform a site specific risk assessment for your entire facility. You may use any scientifically accepted peer reviewed assessment methodology for your site specific risk assessment. An example approach to performing a site specific assessment for air toxics is provided in the " Air Toxics Risk Assessment Reference Library", which may be obtained through the EPA's Air Toxics Website at www. epa. gov/ ttn/ atw.

( 1) Your facility is eligible for the HCl alternative compliance option if your site specific risk assessment demonstrates that the HI from respiratory HAP is less than 1.0.

( 2) Your facility is eligible for the manganese alternative compliance option if your site specific risk assessment demonstrates the risk from manganese emissions is less than 1.0.

( b) Your site specific risk assessment should:

( 1) focus on estimating long term inhalation exposures through the estimation of annual or multi year average ambient concentrations;

( 2) focus on estimating the inhalation exposure of the individual most exposed to the facility's emissions;

( 3) not assume any attenuation of exposure concentrations due to the penetration of outdoor pollutants into indoor exposure areas;

( 4) not assume any reaction or deposition of the emitted pollutants during transport from the emission point to the point of exposure;

( 5) use site specific, quality assured data wherever possible;

( 6) use health protective default assumptions wherever site specific data are not available, and;

( 7) contain adequate documentation of the data and methods used for the assessment that it can be reproduced by an experienced risk assessor.

8. What must my risk based eligibility demonstration contain?

( a) Your risk based eligibility demonstration must contain the information specified in paragraphs ( a)( 1) through ( 6) of this section.

( 1) Identification of each appropriate emission point at the affected source.

( 2) Stack parameters for each appropriate emission point including, but not limited to, the parameters listed in ( a)( 2)( i) through ( iv) below:

( i) Emission release type ( ii) Stack height, stack area, stack gas temperature, and stack gas exit velocity ( iii) Plot plan showing all emission points, nearby residences, and fenceline.

( iv) Identification of any control devices used to reduce emissions from each appropriate emission point.

( 3) Emission test reports for each appropriate emission point based on the test methods specified in Table 1 of this appendix, including a description of the process parameters identified as being worst case.

( 4) Identification of the RfC values used in your sitespecific risk assessment, according to section 5( b) of this appendix.

( 5) Calculations used to determine the toxicity weighted emission rates expressed in HCl equivalents according to section 6( a) of this appendix.

( 6) Identification of the controlling process factors ( including, but not limited to, fuel type, heat input rate, type of control devices, process parameters documented as worst case conditions during the emissions testing used for your eligibility demonstration) that will become Federally enforceable permit conditions used to show that your facility remains eligible for the risk based provisions.

( b) If you use the look up table analysis in section 5 of this appendix to demonstrate that your facility is eligible for either the risk based exemption or the risk based exclusion,

your eligibility demonstration must contain the information in paragraphs ( a) and ( b)( 1) through ( 3) of this section.

( 1) Calculations used to determine the average stack height of the appropriate emission points.

( 2) Identification of the appropriate emission point with the nearest distance to the closest boundary of the nearest residential ( or residentially zoned) area used for fenceline distance.

( 3) Comparison of the values in the look up tables ( Tables 2 and 3 of this appendix) to your maximum toxicity weighted hourly emission rates.

( c) If you are using a site specific risk assessment as described in section 7 of this appendix to demonstrate that your facility is eligible, your eligibility demonstration must contain the information in paragraphs ( a) and ( c)( 1) through ( 7)

of this section:

( 1) Identification of the risk assessment methodology used.

( 2) Documentation of the fate and transport model used.

( 3) Documentation of the fate and transport model inputs,

including the information described in paragraphs ( a)( 1) through ( 5) of this section converted to the dimensions required for the model and all of the following that apply: meteorological data;

building, land use, and terrain data; receptor locations and population data; and other facility specific parameters input into the model.

( 4) Documentation of the fate and transport model outputs.

( 5) Documentation of any exposure assessment and risk characterization calculations ( 6) Comparison of the maximum chronic HI to the HI limit of 1.0.( 1 or 0.5, .

9. When do I have to complete and submit my risk based eligibility demonstration?

( a) If you have an existing affected source, you must complete and submit your low risk demonstration to your permitting authority, along with a signed certification that the demonstration is an accurate depiction of your facility, no later than the date one year after the effective date of subpart DDDDD.

( b) If you have a new or reconstructed affected source that starts up before the effective date of subpart DDDDD, or an affected source that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP before the effective date of subpart DDDDD, then you must comply with the requirements of subpart DDDDD until your eligibility demonstration is completed and submitted to your permitting authority.

( c) If you have a new or reconstructed affected source that starts up after the effective date for subpart DDDDD, or an affected source that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP after the effective date for subpart DDDDD, then you must follow the schedule in paragraphs ( 1) and ( 2) of this section.

( 1) You must complete and submit for approval a preliminary eligibility demonstration based on the information ( e. g.,

equipment types, estimated emission rates, etc.) used to obtain your title V permit. You must base your preliminary eligibility demonstration on the maximum emissions allowed under your title V permit. If EPA concludes that your affected source facility appears to be eligible for either risk based compliance alternative based on this preliminary eligibility demonstration,

then your may start up your new affected source without either complying with the HCl emission limit and corresponding compliance requirements in subpart DDDDD or including manganese in your total selected metals calculations.

( 2) You must conduct the emission tests specified in section 4 of this appendix upon initial startup and use the results of these emissions tests to complete and submit your eligibility demonstration within 180 days following your initial startup date. To be eligible, you must meet the criteria in section 11 of this appendix within 18 months following initial startup of your affected source.

10. When do I become eligible for the risk based alternative compliance options?

To be eligible for either the risk based alternative compliance option for HCl or manganese , you must meet the criteria in paragraphs ( a) and ( b) of this section. If you do not meet these criteria, then your affected source is subject to the applicable emission limits, operating limits, and work practice standards in Subpart DDDDD.

( b) The parameters that defined your affected source as eligible for the risk based provisions ( including, but not limited to, fuel type, type of control devices, process parameters documented as worst case conditions during the emissions testing used for your eligibility demonstration) must be incorporated as Federally enforceable limits into your title V permit. 11. How do I ensure that my facility remains eligible for the risk based provisions?

( a) You must update your eligibility demonstration and resubmit it to EPA for re approval each time you have a process change, such that any of the parameters that defined your affected source changes in a way that could result in increased HAP emissions ( including, but not limited to, fuel type, change in type of control device, changes in process parameters documented as worst case conditions during the emissions testing used for your approved eligibility demonstration).

( b) If you are updating your eligibility demonstration to account for an action in paragraph ( a) of this section, then you must perform emission testing according to section 4 of this appendix for the appropriate emission points that may have increased HAP emissions beyond the levels reflected in your previously approved eligibility demonstration due to the process change. You must submit your revised eligibility demonstration to EPA prior to revising your permit to incorporate the process change. If your updated eligibility demonstration indicates that your affected source is no longer eligible for the riskbased provisions, then you must comply with the applicable emission limits, compliance options, and operating requirements in Subpart DDDDD prior to making the process change and revising your permit.

12. What records must I keep?

( a) You must keep records of the information used in developing the eligibility demonstration for your affected source, including all of the information specified in section 8 of this appendix.

13. Definitions.

The definitions in § 63.7575 of subpart DDDDD apply to this appendix. Additional definitions applicable for this appendix are as follows:

Appropriate emission point means a process unit that is reasonably expected to emit the HAP of concern ( HCl, chlorine,

or manganese).

Hazard Index ( HI) means the sum of more than one hazard quotient for multiple substances and/ or multiple exposure pathways.

Hazard Quotient ( HQ) means the ratio of the predicted media concentration of a pollutant to the media concentratation at which no adverse effects are expected. adverse effects are expected. For inhalation exposures, the HQ is calculated as the air concentration divided by the RfC.

Look up table analysis means a risk screening analysis based on comparing the HAP emission rate ( or toxicity weighted HAP emission rate) from the affected source to the maximum allowable HAP emission rates specified in Tables 3 and 4 of this appendix.

Reference Concentration ( RfC) means an estimate ( with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population ( including sensitive subgroups that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from various types of human or animal data, with uncertainty factors generally applied to reflect limitations of the data used.

Worst case operating conditions means operation of a process unit during emissions testing under the conditions that result in the highest HAP emissions or that result in the emissions stream composition ( including HAP and non HAP) that is most challenging for the control device if a control device is used. For example, worst case conditions could include operation of the process unit at maximum throughput with the wood species mix likely to produce the most HAP. Table 1 to Appendix B of Subpart DDDD. Emission Test Methods.

For... You must... Using...

( 1) each emission point select sampling ports' location and the number of traverse points Method 1 of 40 CFR part 60, appendix A.

( 2) each emission point determine velocity and volumetric flow rate; Method 2, 2F, or 2G in appendix A to 40 CFR part 60.

( 3) each emission point conduct gas molecular weight analysis Method 3A or 3B in appendix A to 40 CFR part 60.

( 4) each emission point measure moisture content of the stack gas Method 4 in appendix A to 40 CFR part 60.

( 5) each emission point measure the hydrogen chloride and chlorine emission concentrations Method 26 or 26A in appendix A to 40 CFR part 60.

( 6) each emission point measure the manganese emission concentration Method 29 in appendix A to 40 CFR part 60.

( 7) each emission point convert emissions concentration to lb per MMBtu emission rates. Method 19 F factor methodology in appendix A to part 60 of this chapter. 40 Table 2 to Appendix A of Subpart DDDDD. Allowable toxicity weighted emission rate expressed in HCl equivalents ( lbs/ hr)

fenceline ( m)

Stack ht.( m) 50 100 150 200 250 500 1000 1500 2000 3000 5000 5 114.9 114.9 114.9 114.9 114.9 144.3 287.3 373.0 373.0 373.0 373.0 10 188.5 188.5 188.5 188.5 188.5 195.3 328.0 453.5 434.4 434.4 434.4 20 386.1 386.1 386.1 386.1 386.1 386.1 425.4 580.0 602.7 602.7 602.7 30 396.1 396.1 396.1 396.1 396.1 396.1 436.3 596.2 690.6 807.8 816.5 40 408.1 408.1 408.1 408.1 408.1 408.1 448.2 613.3 715.5 832.2 966.0 50 421.4 421.4 421.4 421.4 421.4 421.4 460.6 631.0 746.3 858.2 1002.8 60 435.5 435.5 435.5 435.5 435.5 435.5 473.4 649.0 778.6 885.0 1043.4 70 450.2 450.2 450.2 450.2 450.2 450.2 486.6 667.4 813.8 912.4 1087.4 80 465.5 465.5 465.5 465.5 465.5 465.5 500.0 685.9 849.8 940.9 1134.8 100 497.5 497.5 497.5 497.5 497.5 497.5 527.4 723.6 917.1 1001.2 1241.3 200 677.3 677.3 677.3 677.3 677.3 677.3 682.3 919.8 1167.1 1390.4 1924.6 Table 3 to Appendix A of Subpart DDDDD. Allowable Manganese Emission Rates ( lbs/ hr) fenceline ( m)

Stack ht.( m) 50 100 150 200 250 500 1000 1500 2000 3000 5000 5 0.29 0.29 0.29 0.29 0.29 0.36 0.72 0.93 0.93 0.93 0.93 10 0.47 0.47 0.47 0.47 0.47 0.49 0.82 1.13 1.09 1.09 1.09 20 0.97 0.97 0.97 0.97 0.97 0.97 1.06 1.45 1.51 1.51 1.51 30 0.99 0.99 0.99 0.99 0.99 0.99 1.09 1.49 1.73 2.02 2.04 40 1.02 1.02 1.02 1.02 1.02 1.02 1.12 1.53 1.79 2.08 2.42 50 1.05 1.05 1.05 1.05 1.05 1.05 1.15 1.58 1.87 2.15 2.51 60 1.09 1.09 1.09 1.09 1.09 1.09 1.18 1.62 1.95 2.21 2.61 70 1.13 1.13 1.13 1.13 1.13 1.13 1.22 1.67 2.03 2.28 2.72 41 80 1.16 1.16 1.16 1.16 1.16 1.16 1.25 1.71 2.12 2.35 2.84 100 1.24 1.24 1.24 1.24 1.24 1.24 1.32 1.81 2.29 2.50 3.10 200 1.69 1.69 1.69 1.69 1.69 1.69 1.71 2.30 2.92 3.48 4.81 42 02/ 05/ 04 revised draft § 63.2231 Does this subpart apply to me?

This subpart applies to you if you meet the criteria in paragraphs ( a) and ( b) of this section, except for facilities that are part of the low risk subcategory of PCWP manufacturing facilities as specified in appendix B to this subpart.

( a) You own or operate a plywood and composite wood products ( PCWP) manufacturing facility. A PCWP manufacturing facility is a facility that manufactures plywood and/ or composite wood products by bonding wood material ( fibers,

particles, strands, veneers, etc.) or agricultural fiber,

generally with resin under heat and pressure, to form a structural panel or engineered wood product. Plywood and composite wood products manufacturing facilities also include facilities that manufacture dry veneer and lumber kilns located at any facility. Plywood and composite wood products include ( but are not limited to) plywood, veneer, particleboard,

oriented strandboard, hardboard, fiberboard, medium density fiberboard, laminated strand lumber, laminated veneer lumber,

wood I joists, kiln dried lumber, and glue laminated beams.

( b) The PCWP manufacturing facility is located at a major 43 source of HAP emissions. A major source of HAP emissions is any stationary source or group of stationary sources within a contiguous area and under common control that emits or has the potential to emit any single HAP at a rate of 9.07 megagrams ( 10 tons) or more per year or any combination of HAP at a rate of 22.68 megagrams ( 25 tons) or more per year. 44 Appendix B to Subpart DDDD   Methodology and Criteria for Demonstrating That An Affected Source is Part of the Low risk Subcategory of Plywood and Composite Wood Products Manufacturing Facilities 1. Purpose This appendix provides the methodology and criteria for demonstrating that your affected source is part of the low risk subcategory of plywood and composite wood products ( PCWP)

manufacturing facilities. You must determine if your facility is part of the low risk subcategory using either a look up table analysis ( based on the look up tables included in this appendix)

or using a site specific risk assessment performed according to the criteria specified in this appendix. This appendix also specifies how and when you must obtain approval of the low risk demonstrations for your affected source and how to ensure that your affected source remains in the low risk subcategory of PCWP facilities.

2. Who is eligible to demonstrate that they are part of the lowrisk subcategory of PCWP facilities?

Each new, reconstructed, or existing affected source at a 45 PCWP manufacturing facility may demonstrate that they are part of the low risk subcategory of PCWP facilities. Section § 63.2232 of subpart DDDD defines the affected source and explains which affected sources are new, existing, or reconstructed.

3. What parts of my facility have to be included in the low risk demonstration?

Every process unit that is part of the PCWP affected source ( as defined in § 63.2292 of subpart DDDD) and that emits one or more HAP listed in Table 1 of this appendix must be included in the low risk demonstration. You are not required to include process units outside of the affected source in the low risk demonstration.

4. What are the criteria for determining if my facility is low risk?

( a) Determine the individual HAP emission rates from each process unit within the affected source using the procedures specified in section 5 of this appendix.

( b) Perform chronic and acute risk assessments using the 46 dose response values found at http:// www. epa. gov/ ttn/ atw/ toxsource/ summary. html, as specified in paragraphs ( b)( 1) and ( 2) of this section.

( 1) For a look up table analysis or site specific chronic inhalation risk assessment, you should use the cancer and noncancer dose response values listed on the EPA Air Toxics website ( http:// www. epa. gov/ ttn/ atw/ toxsource/ summary. html) to estimate carcinogenic and non carcinogenic chronic inhalation risk, respectively.

( 2) For site specific acute inhalation risk assessment, you must use the acute exposure guidance level ( AEGL 1) value for acrolein and the California EPA ( CalEPA) acute reference exposure level ( REL) value for formaldehyde for estimating acute inhalation risk.

( c) Determine if your facility is part of the low risk subcategory by estimating the maximum chronic and acute impacts of your facility using one of the methods described in either section 6 of this appendix ( look up table analysis) or section 7 of this appendix ( site specific risk assessment) and comparing the results to the low risk criteria. Your facility is low risk if the estimated maximum individual lifetime cancer risk is less 47 than 1 in a million, the estimated maximum chronic hazard index values for respiratory effects and central nervous system ( CNS)

effects are less than 1, and the estimated maximum acute hazard quotient values for acrolein and formaldehyde are less than 1.

5. How do I determine HAP emissions from my affected source?

( a) You must conduct HAP emissions tests according to the requirements in paragraphs ( b) through ( g) of this section and the methods specified in Table 2 of this appendix for every process unit within the affected source that emits one or more of the HAP listed in Table 1. You must test the process units at your facility to obtain the emission rates in pounds per hour ( lb/ hr) for each of the pollutants listed in Table 1.

( b) Periods when emissions tests must be conducted.

( 1) You must not conduct emissions tests during periods of startup, shutdown, or malfunction, as specified in § 63.7( e)( 1).

( 2) You must test under worst case operating conditions as defined in this appendix. You must describe your worst case operating conditions in your performance test report for the process and control systems ( if applicable) and explain why the conditions are worst case. 48 ( c) Number of test runs. You must conduct three separate test runs for each test required in this section, as specified in § 63.7( e)( 3). Each test run must last at least 1 hour except for: testing of a temporary total enclosure ( TTE) conducted using Methods 204A through 204F which require three separate test runs of at least 3 hours each; and testing of an enclosure conducted using the alternative tracer gas method in appendix A to subpart DDDD which requires a minimum of three separate runs of at least 20 minutes each.

( d) Sampling locations. Sampling sites must be located at the outlet of the control device, including wet control devices,

and prior to any releases to the atmosphere.

( e) Collection of monitoring data for HAP control devices.

During the emissions test, you must collect operating parameter monitoring system or continuous emissions monitoring system ( CEMS) data at least every 15 minutes during the entire emissions test and establish the site specific operating requirements ( including the parameter limits or total hydrocarbon ( THC) concentration limit) in Table 2 of subpart 49 DDDD using data from the monitoring system and the procedures specified in paragraphs ( k) through ( o) of § 63.2262 of subpart DDDD.

( f) Nondetect data. You may treat emissions of an individual HAP as zero if all of the test runs result in a nondetect measurement and the conditions in paragraphs ( 1) and ( 2) are met for the relevant test method. Otherwise nondetect data ( as defined in § 63.2292 of subpart DDDD) for individual HAP must be treated as one half of the method detection limit.

( 1) The method detection limit is less than or equal to 1 part per million by volume, dry ( ppmvd) for pollutant emissions measured using Method 320 in appendix A to 40 CFR part 63; or the NCASI Method IM/ CAN/ WP 99.02; or ASTM D6348 03.

( 2) For pollutants measured using Method 29 in appendix A to 40 CFR part 60, you analyze samples using atomic absorption spectroscopy ( AAS).

( g) For purposes of your low risk demonstration, assume that 17 percent of your total chromium measured using EPA Method 29 in appendix A to 40 CFR part 60 is chromium ( VI). For purposes of your low risk demonstration, assume that 65 percent 50 of your total nickel measured using EPA Method 29 in appendix A to 40 CFR part 60 is nickel subsulfide.

6. How do I conduct a look up table analysis?

Use the look up tables to determine if your facility is part of the low risk subcategory, following the procedures in paragraphs ( a) through ( d) of this section.

( a) Using the emission rate of each HAP required to be included in your low risk demonstration, determine your total toxicity weighted carcinogen and non carcinogen emission rates for each of your process units using Equations 1 and 2 of this appendix, respectively.

TWCER =

( ERi x UREi) Eqn. 1 TWCER = Toxicity weighted carcinogenic emission rate,

( lb/ hr)/(

g/ m3)

ERi = Emission rate of pollutant i, pounds per hour ( lb/ hr)

UREi = Unit risk estimate for pollutant i, 1 per microgram per cubic meter (

g/ m3) 1 51 TWNER =

( ERi / RfCi) Eqn. 2 TWNER = Toxicity weighted non carcinogenic emission rate,

( lb/ hr)

ERi = Emission rate of pollutant i, pounds per hour ( lb/ hr)

RfCi = Reference concentration for pollutant i,

milligrams per cubic meter ( mg/ m3)

REAG: PLEASE CONFIRM UNITS IN TABLE AND EQUATION ( b) Cancer risk. Determine the total toxicity weighted carcinogen emission rate for your affected source by summing the toxicity weighted carcinogen emission rates for each of your process units. Select the maximum allowable toxicity weighted carcinogen emission rate from Table 3 of this appendix for your facility using the average stack height of your process units and the minimum distance between any HAP emission point at the facility and the closest boundary of the nearest residential, or residentially zoned, area. If one or both of these values do not match the values in the lookup tables then use the next lowest table value. Your facility is low risk for carcinogenic 52 effects if your toxicity weighted carcinogen emission rate,

determined using the methods specified in this appendix, does not exceed the values specified in Table 3 of this appendix.

( c) Non cancer risk. Determine the total CNS and respiratory target organ specific toxicity weighted noncarcinogen emission rate for your affected source by summing the toxicity weighted emission rates for each of your emission points. Select the maximum allowable toxicity weighted noncarcinogen emission rate from Table 4 of this appendix for your facility using the average stack height of your process units and the minimum distance between any HAP emission point at the facility and the closest boundary of the nearest residential, or residentially zoned, area. If one or both of these values do not match the values in the lookup tables then use the next lowest table value. Your facility is low risk for noncarcinogenic effects if your toxicity weighted non carcinogen emission rate, determined using the methods specified in this appendix, does not exceed the values specified in Table 4 of this appendix.

( d) Low risk demonstration. Your facility is part of the low risk subcategory of PCWP sources if your affected source is determined to be low risk for both carcinogenic and non 53 carcinogenic effects using the look up table analysis described in this section and you meet the criteria specified in Section 11 of this appendix.

7. How do I conduct a site specific risk assessment?

Perform a site specific risk assessment following the procedures specified in this section. You may use any scientifically accepted peer reviewed assessment methodology for your site specific risk assessment. An example approach to performing a site specific risk assessment for air toxics is provided in the " Air Toxics Risk Assessment Guidance Reference Library". You may obtain a copy of the " Air Toxics Risk Assessment Reference Library" from EPA's air toxics website [ need to specify address].

( a) Your facility is low risk for carcinogenic chronic inhalation effects if your site specific risk assessment demonstrates that maximum off site individual lifetime cancer risk at a location where people can live is less than one in one million.

( b) Your facility is low risk for non carcinogenic chronic inhalation effects if your site specific risk assessment 54 demonstrates that every maximum off site target organ specific hazard index ( TOSHI) at a location where people can live is less than 1.

( c) Your facility is low risk for non carcinogenic acute inhalation effects if your site specific risk assessment demonstrates that the maximum off site acute hazard quotients for both acrolein and formaldehyde are less than 1.

( d) Your facility is part of the low risk subcategory of PCWP facilities if the affected source is determined to be low risk for all of the applicable effects listed in paragraphs ( a)

through ( c) of this section and you meet the criteria specified in section 11 of this appendix.

8. What information must I submit for the low risk demonstration?

( a) Your low risk demonstration must include the information specified in paragraphs ( a)( 1) through ( 5) of this section and the information specified in either paragraph ( b) or ( c) of this section.

( 1) Identification of each process unit at the affected source. 55 ( 2) Stack parameters for each HAP emission point including,

but not limited to, the parameters listed in ( a)( 2)( i) through ( iv) below:

( i) Emission release type.

( ii) Stack height, stack area, stack gas temperature, and stack gas exit velocity.

( iii) Plot plan showing all HAP emission points, nearby residences, and fenceline.

( iv) Identification of any HAP control devices used to reduce emissions from each process unit.

( 3) Emission test reports for each process unit based on the test methods specified in Table 2 of this appendix,

including a description of the process parameters identified as being worst case.

( 4) Identification of the dose response values used in your risk analysis ( look up table analysis or site specific risk assessment), according to section 5( b) of this appendix.

( 5) Identification of the controlling process factors ( including, but not limited to, production rate, annual emission rate, type of control devices, process parameters documented as worst case conditions during the emissions testing used for your low risk demonstration) that will become Federally enforceable 56 permit conditions used to show that your facility remains in the low risk subcategory.

( b) If you use the look up table analysis in section 6 of this appendix to demonstrate that your facility is low risk,

your low risk demonstration must contain the information in paragraphs ( a) and ( b)( 1) through ( 4) of this section.

( 1) Identification of the process unit stack heights included in the calculation of average stack height.

( 2) Identification of the process unit with the nearest distance to a residential, or residentially zoned, area.

( 3) Calculations used to determine the toxicity weighted carcinogen and non carcinogen emission rates according to section 6( a) of this appendix.

( 4) Comparison of the values in the look up tables ( Tables 3 and 4 of this appendix) to your toxicity weighted emission rates for carcinogenic and non carcinogenic HAP.

( c) If you are using a site specific risk assessment as described in section 7 of this appendix to demonstrate that your facility is low risk ( for carcinogenic and non carcinogenic chronic inhalation and acute inhalation risks), your low risk 57 demonstration must contain the information in paragraphs ( a) and ( c)( 1) through ( 8) of this section:

( 1) Identification of the risk assessment methodology used.

( 2) Documentation of the fate and transport model used.

( 3) Documentation of the fate and transport model inputs,

including the information described in paragraphs ( a)( 1) through ( 4) of this section converted to the dimensions required for the model and all of the following that apply: meteorological data;

building, land use, and terrain data; receptor locations and population data; and other facility specific parameters input into the model.

( 4) Documentation of the fate and transport model outputs.

( 5) Documentation of exposure assessment and risk characterization calculations.

( 6) Comparison of the carcinogenic inhalation risk to 1 in a million, as required in section 7( a) of this appendix.

( 7) Comparison of each chronic inhalation TOSHI ( for respiratory effects and CNS effects) to the limit of 1, as required in section 7( b) of this appendix.

( 8) Comparison of the acute inhalation HQ to the limit of 1, as required in section 7( c) of this appendix. 58 9. Where do I send my low risk demonstration?

You must submit your low risk demonstration to EPA for review and approval. Send your low risk demonstration to U. S.

EPA, Risk and Exposure Assessment Group, Emission Standards Division ( C404 01), Attn: Dr. David Guinnup, Research Triangle Park, NC 27711. You are not part of the low risk subcategory until you meet the requirements of section 11 of this appendix.

10. When do I submit my low risk demonstration?

( a) If you have an existing affected source, you must complete and submit for approval your low risk demonstration no later than [ INSERT 14 MONTHS AFTER DATE OF PUBLICATION].

( b) If you have a new or reconstructed affected source that starts up before the effective date of subpart DDDD, or an affected source that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP before [ INSERT 2 MONTHS AFTER PUBLICATION], then you must comply with the requirements of subpart DDDD until you meet the criteria in section 11 of this appendix. 59 ( c) If you have a new or reconstructed affected source that starts up after [ INSERT 2 MONTHS AFTER PUBLICATION], or an affected source that is an area source that increases its emissions or its potential to emit such that it becomes a major source of HAP after [ INSERT 2 MONTHS AFTER PUBLICATION], then you must follow the schedule in paragraphs ( 1) and ( 2) of this section.

( 1) You must complete and submit for approval a preliminary low risk demonstration based on the information ( e. g., equipment types, estimated emission rates, etc.) used to obtain your title V permit. You must base your preliminary low risk demonstration on the maximum emissions allowed under your title V permit. If EPA concludes that your affected source appears to be part of the low risk subcategory based on this preliminary low risk demonstration, then your may start up your affected source without complying with the compliance options, operating requirements, and work practice requirements in subpart DDDD.

( 2) You must conduct the emission tests specified in section 4 of this appendix upon initial startup and use the results of these emissions tests to complete and submit your low risk demonstration within 180 days following your initial 60 startup date. To be included in the low risk subcategory, you must meet the criteria in section 11 of this appendix within 18 months following initial startup of your affected source.

11. How does my facility become part of the low risk subcategory?

To be included in the low risk subcategory, you must meet the criteria in paragraphs ( a) and ( b) of this section. If you do not meet these criteria, then your affected source is subject to the applicable compliance options, operating requirements,

and work practice requirements in Subpart DDDD.

( a) Your demonstration of low risk must be approved by EPA.

( b) The parameters that defined your affected source as part of the low risk subcategory ( including, but not limited to,

production rate, annual emission rate, type of control devices,

process parameters documented as worst case conditions during the emissions testing used for your low risk demonstration) must be incorporated as Federally enforceable limits into your title V permit.

12. What must I do to ensure my facility remains a low risk 61 facility?

( a) You must meet the requirements in Table 2 of subpart DDDD for each HAP control device used at the time when you completed your low risk demonstration. You must monitor and collect data according to § 63.2270 of subpart DDDD to show continuous compliance with your control device operating requirements. You must demonstrate continuous compliance with the control device operating requirements that apply to you by collecting and recording the monitoring system data listed in Table 2 of this subpart for the process unit according to § § 63.2269( a), ( b), and ( d) of subpart DDDD; AND reducing the monitoring system data to the specified averages in units of the applicable requirement according to calculations in § 63.2270 of subpart DDDD; AND maintaining the average operating parameter at or above the minimum, at or below the maximum, or within the range ( whichever applies) established according to section 4( e)

of this appendix.

13. What happens if the critera used in the risk determination change? 62 ( a) You must certify with each Title V permit renewal that the basis for your facility's low risk determination has not changed. You must submit this certification to the permitting authority. You must consider the following:

( 1) Process changes that increases HAP emissions,

including, but not limited to, production rate increase, annual emission rate increase, change in type of control device,

changes in process parameters documented as worst case conditions during the emissions testing used for your approved low risk demonstration.

( 2) Population shifts.

( 3) Unit risk estimate increases.

( 4) Reference concentration decreases.

( 5) Dose response values ( URE, RfC, CSF, and RfD) on the EPA website ( http:// www. epa. gov/ ttn/ atw/ toxsource/ summary. html).

( b) At any time a change occurs that was not a permit condition, including the changes listed in paragraphs ( a)( 1)

through ( 5), you must notify the permitting authority immediately.

( 1) If the change does not change the risk designation of the facility, you must explain the change and why the facility 63 is still low risk. You must also certify that the facility is still low risk and part of the low risk subcategory.

( 2) If the change results in the facility no longer being low risk, then the facility is no longer part of the low risk subcategory and is subject to all the applicable requirements of subpart DDDD.

( 3) If your facility is no longer low risk, you may update your low risk demonstration and resubmit it to EPA. You must submit your revised low risk demonstration to EPA prior to revising your permit to incorporate the process change. If you use the same approach/ risk assessment model, you may . . .

[ text needed if possible to expedite reveiw   REAG] time 14. What records must I keep?

( a) You must keep records of the information used in developing the low risk demonstration for your affected source,

including all of the information specified in section 8 of this appendix.

( b) You must keep the records required in section 12( d) of this appendix to show continuous compliance with the operating requirements for control devices. 64 ( c) For each THC CEMS, you must keep the records specified in § 63.2282( c) of subpart DDDD.

15. Definitions.

The definitions in § 63.2292 of subpart DDDD apply to this appendix. Additional definitions applicable for this appendix are as follows:

Direct fired process unit means a process unit that is heated by the passing of combustion exhaust directly through the process unit such that the process material is contacted by the combustion exhaust.

Hazard Index ( HI) means the sum of more than one hazard quotient for multiple substances and/ or multiple exposure pathways.

Hazard Quotient ( HQ) means the ratio of the predicted media concentration of a pollutant to the media concentration at which no adverse effects are expected. For inhalation exposures, the HQ is calculated as the air concentration divided by the RfC. 65 Look up table analysis means a risk screening analysis based on comparing the toxicity weighted HAP emission rate from the affected source to the maximum allowable toxicity weighted HAP emission rates specified in Tables 3 and 4 of this appendix.

Reference Concentration ( RfC) means an estimate ( with uncertainty spanning perhaps an order of magnitude) of a continuous inhalation exposure to the human population ( including sensitive subgroups) that is likely to be without an appreciable risk of deleterious effects during a lifetime. It can be derived from various types of human or animal data, with uncertainty factors generally applied to reflect limitations of the data used.

Target organ specific hazard index ( TOSHI) means the sum of hazard quotients for individual chemicals that affect the same organ or organ system ( e. g., respiratory system, central nervous system).

Unit Risk Estimate ( URE) means the upper bound excess lifetime cancer risk estimated to result from continuous exposure to an agent at a concentration of 1

g/ m3 in air. 66 Worst case operating conditions means operation of a process unit during emissions testing under the conditions that result in the highest HAP emissions or that result in the emissions stream composition ( including HAP and non HAP) that is most challenging for the control device if a control device is used. For example, worst case conditions could include operation of the process unit at maximum throughput, at its highest temperature, with the wood species mix likely to produce the most HAP, and/ or with the resin formulation containing the greatest HAP. 67 Table 1 to Appendix B of Subpart DDDD. HAP that must be included in the demonstration of eligibility for the low risk PCWP subcategory.

For your analysis of the following effects... You must include the following HAP...

( 1) Chronic inhalation cancer acetaldehyde, benzene, arsenic, beryllium, cadmium, chromium, lead, nickel, formaldehyde.

( 2) Chronic inhalation noncancer respiratory acetaldehyde, acrolein, formaldehyde, MDI.

( 3) Chronic inhalation noncancer CNS manganese, phenol.

( 4) Acute inhalation acrolein, formaldehyde. 68 Table 2 to Appendix B of Subpart DDDD. Emission Test Methods.

For... You must... Using...

( 1) each process unit select sampling ports' location and the number of traverse points Method 1 or 1A of 40 CFR part 60, appendix A ( as appropriate).

( 2) each process unit determine velocity and volumetric flow rate; Method 2 in addition to Method 2A, 2C, 2D, 2F, or 2G in appendix A to 40 CFR part 60 ( as appropriate).

( 3) each process unit conduct gas molecular weight analysis Method 3, 3A, or 3B in appendix A to 40 CFR part 60 ( as appropriate).

( 4) each process unit measure moisture content of the stack gas Method 4 in appendix A to 40 CFR part 60.

( 5) each process unit measure emissions of the following HAP: acetaldehyde, acrolein, formaldehyde, and phenol NCASI Method IM/ CAN/ WP 99.02; OR Method 320 in appendix A to 40 CFR part 63; OR ASTM D6348 03 provided that % R as determined in Annex A5 of ASTM D6348 03 is equal or greater than 70% and less than or equal to 130%.

( 6) each process unit measure emissions of benzene Method 320 in appendix A to 40 CFR part 63; OR ASTM D6348 03 provided that % R as determined in Annex A5 of ASTM D6348 03 is equal or greater than 70% and less than or equal to 130%.

( 7) each press that processes board containing methylene diphenyl diisocyanate ( MDI) resin measure emissions of MDI Method 320 in appendix A to 40 CFR part 63; OR Conditional Test Method ( CTM) 031 which is posted on http:// www. epa. gov/ ttn/ emc/ ctm. html ( 8) each direct fired process unit measure emissions of the following HAP metals: arsenic, beryllium, cadmium, chromium, lead, manganese, and nickel. Method 29 in appendix A to 40 CFR part 60. You must analyze samples using atomic absorption spectroscopy ( AAS).

( 9) any process unit that is known to emit HAP not otherwise listed in this table measure emissions of the HAP emitted the methods specified in this table ( as appropriate) or petition the Administrator for approval of an alternative test method. 69 ( 11) each reconstituted wood product press or reconstituted wood product board cooler with a HAP control device meet the design specifications included in the definition of wood products enclosure in § 63.2292 of subpart DDDD OR determine the percent capture efficiency of the enclosure directing emissions to an add on control device Methods 204 and 204A through 204F of 40 CFR part 51, appendix M to determine capture efficiency ( except for wood products enclosures as defined in § 63.2292). Enclosures that meet the definition of wood products enclosure or that meet Method 204 requirements for a PTE are assumed to have a capture efficiency of 100%. Enclosures that do not meet either the PTE requirements or design criteria for a wood products enclosure must determine the capture efficiency by constructing a TTE according to the requirements of Method 204 and applying Methods 204A through 204F ( as appropriate). As an alternative to Methods 204 and 204A through 204F, you may use the tracer gas method contained in appendix A to this subpart.

( 12) each reconstituted wood product press or reconstituted wood product board cooler determine the percent capture efficiency a TTE and Methods 204 and 204A through 204F ( as appropriate) of 40 CFR part 51, appendix M. As an alternative to installing a TTE and using Methods 204 and 204A through 204F, you may use the tracer gas method contained in appendix A to this subpart.

( 13) each process unit with a HAP control device establish the sitespecific operating requirements ( including the parameter limits or THC concentration limits) in Table 2 of subpart DDDD data from the parameter monitoring system or THC CEMS and the applicable performance test method( s). 70 Table 3 to Appendix B of Subpart DDDD. Maximum allowable toxicity weighted carcinogen emission rate ( lb/ hr)/(

g/ m3)

Fenceline ( m)

Stack height ( m) 0 50 100 150 200 250 500 1000 1500 2000 3000 5000 5 8.72E 07 8.72E 07 8.72E 07 9.63E 07 1.25E 06 1.52E 06 1.25E 06 4.25E 06 4.39E 06 4.39E 06 4.39E 06 5.00E 06 10 2.47E 06 2.47E 06 2.47E 06 2.47E 06 2.47E 06 2.61E 06 3.58E 06 5.03E 06 5.89E 06 5.89E 06 5.89E 06 6.16E 06 20 5.81E 06 5.81E 06 5.81E 06 5.81E 06 5.81E 06 5.81E 06 5.90E 06 7.39E 06 8.90E 06 9.97E 06 9.97E 06 1.12E 05 30 7.74E 06 7.74E 06 7.74E 06 7.74E 06 7.74E 06 7.74E 06 8.28E 06 9.49E 06 1.17E 05 1.35E 05 1.55E 05 1.61E 05 40 9.20E 06 9.20E 06 9.20E 06 9.20E 06 9.20E 06 9.20E 06 9.24E 06 1.17E 05 1.34E 05 1.51E 05 1.98E 05 2.22E 05 50 1.02E 05 1.02E 05 1.02E 05 1.02E 05 1.02E 05 1.02E 05 1.02E 05 1.36E 05 1.53E 05 1.66E 05 2.37E 05 2.95E 05 60 1.13E 05 1.13E 05 1.13E 05 1.13E 05 1.13E 05 1.13E 05 1.13E 05 1.53E 05 1.76E 05 1.85E 05 2.51E 05 3.45E 05 70 1.23E 05 1.23E 05 1.23E 05 1.23E 05 1.23E 05 1.23E 05 1.23E 05 1.72E 05 2.04E 05 2.06E 05 2.66E 05 4.07E 05 80 1.34E 05 1.34E 05 1.34E 05 1.34E 05 1.34E 05 1.34E 05 1.34E 05 1.92E 05 2.15E 05 2.31E 05 2.82E 05 4.34E 05 100 1.52E 05 1.52E 05 1.52E 05 1.52E 05 1.52E 05 1.52E 05 1.52E 05 1.97E 05 2.40E 05 2.79E 05 3.17E 05 4.49E 05 200 1.76E 05 1.76E 05 1.76E 05 1.76E 05 1.76E 05 1.76E 05 1.76E 05 2.06E 05 2.94E 05 3.24E 05 4.03E 05 5.04E 05 MIR= 1E 06 Emission rates in table expressed as equivalents normalized to theoretical HAP with URE = 1(

g/ m 3) 1 71 Table 4 to Appendix B of Subpart DDDD. Maximum allowable toxicity weighted noncarcinogen emission rate ( lb/ hr)

Fenceline ( m)

Stack height ( m) 0 50 100 150 200 250 500 1000 1500 2000 3000 5000 5 2.51E 01 2.51E 01 3.16E 01 3.16E 01 3.16E 01 3.16E 01 3.16E 01 3.46E 01 4.66E 01 6.21E 01 9.82E 01 1.80E+ 00 10 5.62E 01 5.62E 01 5.62E 01 5.62E 01 5.62E 01 5.62E 01 5.62E 01 5.70E 01 6.33E 01 7.71E 01 1.13E+ 00 1.97E+ 00 20 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.43E+ 00 1.68E+ 00 1.83E+ 00 2.26E+ 00 3.51E+ 00 30 2.36E+ 00 2.36E+ 00 2.36E+ 00 2.36E+ 00 2.36E+ 00 2.36E+ 00 2.53E+ 00 3.04E+ 00 3.04E+ 00 3.33E+ 00 4.45E+ 00 5.81E+ 00 40 3.11E+ 00 3.11E+ 00 3.11E+ 00 3.11E+ 00 3.11E+ 00 3.11E+ 00 3.42E+ 00 4.04E+ 00 5.07E+ 00 5.51E+ 00 6.39E+ 00 9.63E+ 00 50 3.93E+ 00 3.93E+ 00 3.93E+ 00 3.93E+ 00 3.93E+ 00 3.93E+ 00 4.49E+ 00 4.92E+ 00 6.95E+ 00 7.35E+ 00 8.99E+ 00 1.25E+ 01 60 4.83E+ 00 4.83E+ 00 4.83E+ 00 4.83E+ 00 4.83E+ 00 4.83E+ 00 5.56E+ 00 6.13E+ 00 7.80E+ 00 1.01E+ 01 1.10E+ 01 1.63E+ 01 70 5.77E+ 00 5.77E+ 00 5.77E+ 00 5.77E+ 00 5.77E+ 00 5.77E+ 00 6.45E+ 00 7.71E+ 00 8.83E+ 00 1.18E+ 01 1.36E+ 01 1.86E+ 01 80 6.74E+ 00 6.74E+ 00 6.74E+ 00 6.74E+ 00 6.74E+ 00 6.74E+ 00 7.12E+ 00 9.50E+ 00 1.01E+ 01 1.29E+ 01 1.72E+ 01 2.13E+ 01 100 8.87E+ 00 8.87E+ 00 8.87E+ 00 8.87E+ 00 8.87E+ 00 8.87E+ 00 8.88E+ 00 1.19E+ 01 1.37E+ 01 1.55E+ 01 2.38E+ 01 2.89E+ 01 200 1.70E+ 01 1.70E+ 01 1.70E+ 01 1.70E+ 01 1.70E+ 01 1.70E+ 01 1.70E+ 01 2.05E+ 01 2.93E+ 01 3.06E+ 01 4.02E+ 01 4.93E+ 01 HI= 1 Emission rates in table expressed in lbs/ hr as equivalents normalized to theoretical HAP with RfC = 1.0

g/ m 3 [ Question: RfC = ug/ m3 or mg/ m3???] 72 IV. Summary of Responses to Major Comments and Changes to the Plywood and Composite Wood Products NESHAP K. Risk based approaches 1. General comments a. Risk based approaches Comment: Numerous commenters encouraged EPA to exercise all of the flexibility within its authority and offer the widest possible array of options so that facilities that pose no significant risk to public health or the environment would not be forced to add expensive and unproductive control equipment which would weaken them financially or cause them to close. Commenters specifically recommended that EPA incorporate risk based options similar to all three industry " white papers,"

which would exclude facilities that pose no significant risk to public health or the environment. ( As an alternative, one commenter recommended that EPA at least incorporate the concentration based de minimis applicability exemption.)

Commenters stated that inclusion of risk provisions has the potential to achieve overall environmentally superior results in a cost effective manner, particularly in cases where criteria pollutants from control devices 73 ( i. e., incinerators) may result in greater impacts that the HAP emissions that they control. According to a life cycle analysis conducted by one commenter, incinerators used to limit HAP emissions from low risk wood products facilities would create more harm than good through their consumption of electricity and natural gas. The commenter noted that incinerators emit carbon monoxide ( CO2) and criteria pollutants, which could affect a State's ability to meet the National Ambient Air Quality Standards ( NAAQS)

attainment requirements under the CAA. In particular, the commenter referred to EPA's projection that adoption of MACT floor level controls would result in increased emissions of NOx, a precursor to ozone and PM. According to the commenter, the draft rule ( without risk provisions)

would work against the industry's voluntary commitment, in response to President Bush's initiative, to reduce the emissions of greenhouse gases by 12 percent over the next 10 years. The commenter noted that the costly mandatory controls proposed, coupled with stiff foreign competition and regulatory mandates under other MACT rules, would also create significant financial hardship across all sectors of the industry and jeopardize the commercial viability of numerous facilities, many of which are the principal 74 employer in the small, rural towns in which they are located. The projected costs for the proposed rule are enormous amounts of money for an industry already operating at the margin in a depressed economic climate.

Noting EPA's prediction that the draft rule would avert 0.07 cases of cancer per year, or one case every 14 years,

the commenter stated that this would yield a costeffectiveness of $ 2.4 billion per cancer case averted.

The commenter compared the cost per premature death averted for several rules and found the PCWP rule to be one of the more costly. The commenter concluded that, in its current form, the draft rule would impose hundreds of millions of dollars of additional cost with virtually no gain to either the environment or the health. The commenter stated that the draft rule would be one of the most cost ineffective rules ever promulgated by EPA.

According to the commenter, the overwhelming advantage of the risk based approach is that it avoids imposing high costs on low risk facilities, where there is little or no benefit to be gained for either the environment or the public interest. The commenter stated that the wood products industry as a whole poses a small

toinsignificant risk to human health and the environment. 75 The commenter stated that the final rule should include reasonable risk based mechanisms to allow facilities posing no significant risk to limit their emissions below levels of concern without having to install incinerator controls. The commenter stated that facilities wishing to take advantage of the risk based compliance option would take a federally enforceable permit limit that would guarantee that their emissions remain below the risk based emission standard. This would constitute an " emission limitation," within the statutory definition of the term, and it would allow facilities to forego the installation of incinerators where they are not warranted by public health and environmental considerations.

Commenters argued that the risk based options are legally justified, protective of human health and the environment, and economically sensible. Commenters stated that the risk based options are supported under the CAA,

through EPA's authority under sections 112( d)( 4) and 112( c)( 9) to set emission standards other than MACT for certain low risk facilities and delist technology defined low risk subcategories, respectively, and through EPA's inherent de minimis authority to avoid undertaking 76 regulatory action in the absence of meaningful risk. One commenter pointed out that, by meeting the stringent health benchmarks necessary to qualify for the risk based compliance approaches, facilities already would have satisfied the residual risk provisions 8 years ahead of the statutory requirements set forth in section 112( f) of the CAA.

Two commenters believed that the risk based approach would particularly benefit small mills located in rural areas with timber dependent economies. One commenter stated that, by offering manufacturers an opportunity to apply for subcategorization on a sitespecific basis, facilities that are remotely located, or which were originally planned and sited with thorough consideration of airshed impacts, would not be unduly burdened with MACT requirements which yield little or no public health benefits.

Commenters argued that such low risk facilities should not be burdened with the requirements of MACT. One commenter noted that the regulatory framework exists within their State to implement a risk based approach.

Another commenter agreed with the concept of a risk bsed approach but stated that it would not be appropriate for 77 State and local programs to determine which facilities should be exempted from MACT. Another commenter suggested that exemptions be provided on a case by case basis to individual facilities that are able to demonstrate that they pose no significant risk to public health or the environment.

Several commenters opposed the risk based exemptions.

Two commenters stated that the use of risk based concepts to evade MACT applicability is contrary to the intent of the CAA and is based on a flawed interpretation of section 112( d)( 4) written by an industry subject to regulation.

One commenter added that the CAA requires a technologybased floor level of control and does not provide exclusions for risk or secondary impacts in applying the MACT floor. The other commenter was particularly concerned about industry's unprecedented proposal to include " de minimis exemptions" and " cost" in the MACT standard process. The commenter stated that including case by case risk based exemptions would jeopardize the effectiveness of the national air toxics program to adequately protect public health and the environment and to establish a level playing field. A third commenter noted that subcategorization and source category deletions 78 under section 112( c) have been implemented several times since the MACT program began.

Commenters pointed out that they have not been able to comment on the technical merit of the risk analysis employed by the EPA. They argued that, until the residual risk analysis procedures have been implemented via the section 112( f) process, risk analysis should not be used in making MACT determinations pursuant to section 112( d)( 4). Also, risk analysis could never be used to establish a MACT floor.

One commenter pointed out that, in separate rulemakings and lawsuits, EPA adopted legal positions and policies that refute and contradict the very risk based and cost based approaches contained in the proposal. In these other arenas, EPA properly rejected risk assessment to alter the establishment of MACT standards. The EPA also properly rejected cost in determining MACT floors and in denying a basis for avoiding the MACT floor. ( See Brief for Respondent Environmental Protection Agency,

Sierra Club v. EPA; Brief for Respondent Environmental Protection Agency, Cement Kiln Recycling Coalition v. EPA,

No. 99 1457 and consolidated cases, ( D. C. Cir.) ( Jan. 18,

2001); Brief for Respondent Environmental Protection 79 Agency, National Lime Ass'n v. EPA, 233 F. 3D 625 ( D. C.

Cir. 2000) ( July 14, 2000).)

Response: We believe that the assertions by one commenter about the negative environmental disbenefits of the PCWP rule are overstated. We disagree that the PCWP industry as a whole poses a small to insignificant risk to human health and the environment. However, we acknowledge that there are some PCWP facilities that pose little risk to human health and the environment. Consequently, we have included an option in today's final PCWP rule that would allow individual facilities to be delisted ( as part of a low risk subcategory) if they demonstrate that they do not pose a significant risk to human health or the environment. The low risk subcategory delisting in today's final PCWP rule is based on our authority under CAA sections 112( c)( 1) and ( 9). This statute requires that categories or subcategories meet specific risk criteria, and to determine this, risk analyses may be used. We disagree with the commenter that we must wait for implementation of CAA section 112( f) before utilizing risk analysis in this manner. Section 112( d)( 1) of the CAA gives us the authority to distinguish among classes,

types, and sizes of sources within a category. We believe 80 these provisions of the CAA allow us to define a subcategory of sources in terms of risk. Thus, the lowrisk subcategory of PCWP facilities is defined in terms of risk, not cost. We are not subcategorizing or determining MACT floors based on cost. Furthermore, as discussed elsewhere in this section, the MACT level of emissions reduction required by today's final rule is not affected by facilities becoming part of the low risk subcategory.

For many of the reasons provided by the commenters,

we are not pursuing the risk based exemptions based on section 112( d)( 4). We do not believe that a risk based approach based on section 112( d)( 4) is appropriate for the PCWP industry because PCWP facilities emit HAP for which no health thresholds have been established and because the legislative history of the 1990 Amendments to the CAA indicates that Congress considered and rejected allowing us to grant such source specific exemptions from the MACT floor. We also are not relying on de minimis authority.

Legal issues associated with the risk based provisions are addressed elsewhere in this section.

In today's final PCWP rule, we are identifying the criteria we will use to identify low risk PCWP facilities and requesting that any candidate facilities submit 81 information to us based on those criteria so that we can evaluate whether they might be low risk. Today's final PCWP rule also establishes a low risk PCWP subcategory based on the criteria and delists the subcategory based on our finding that no source that would be eligible to be included in the subcategory based on our adopted criteria emits HAP at levels that exceed the thresholds specified in section 112( c)( 9)( B) of the CAA. To be found eligible to be included in the delisted source category, facilities will have to demonstrate to us that they meet the criteria established by today's final PCWP rule and assume federally enforceable limitations that ensure their HAP emissions do not subsequently increase to exceed levels reflected in their eligibility demonstrations.

The criteria defining the low risk subcategory of PCWP facilities are included in Appendix B to Subpart DDDD. The criteria in the appendix were developed for and apply only to the PCWP industry and are not applicable to other industries. Today's final PCWP rule provides two ways that a facility may demonstrate that they are part of the low risk subcategory of PCWP facilities. First,

lookup tables allow facilities to determine, using a limited number of site specific input parameters, whether 82 emissions from their sources might cause an HI limit for non carcinogens or a cancer benchmark of one in a million to be exceeded. Second, a tiered modeling approach ( each tier less conservative and more complex than the previous)

can be used by those facilities that cannot demonstrate that they are part of the low risk subcategory using the look up tables.

The low risk subcategory delisting that is included in today's final PCWP rule is intended to avoid imposing unnecessary controls on facilities that do not pose a significant risk to human health or the environment.

Facilities will have to select controls or other methods of limiting risk and then demonstrate, using Appendix B to Subpart DDDD and/ or the " Air Toxics Risk Assessment Reference Library," that their emissions qualify them to be included in the low risk subcategory, and, therefore,

are not subject to the compliance options included in today's final PCWP rule.

Comment: Several commenters objected to EPA using the preambles of individual rule proposals as the forum for introducing significant changes in the way that MACT standards are established. One commenter stated that, for many years, they have coordinated with EPA on development 83 of MACT standards for the national air toxics program, and there has been no indication of any kind regarding inclusion of risk based exemptions in the first phase of the MACT program. The commenter thought it was unprecedented and alarming that EPA was proposing such a radical change at the end of Phase 1 of the MACT standard process. The commenter believed that allowing risk based exemptions requires changes to existing law and that such a debate should take place within the democratic legislative process and not in the MACT standard process.

Another commenter stated that precedent setting change of the magnitude that EPA has raised should be discussed openly and carefully with all affected parties instead of being buried in the preambles of individual standards. A third commenter expressed concern that other parties may miss commenting on the risk based exemptions because they are contained within six separate proposals. The commenter added that to give the issue full consideration,

the risk provisions should not be adopted within any of the final rules but should be addressed in one place, such as in revisions to the General Provisions of 40 CFR Part 63, Subpart A.

Response: The discussion of risk based provisions in 84 MACT was included in individual proposals for several reasons. First, we recognize that such provisions are only appropriate for certain source categories, and our decision making process required source category specific input from stakeholders. Second, the 10 year MACT standards, which are now being completed, are the last group of MACT standards currently planned for development,

and for any risk provisions to be useful, the provisions must be finalized in a timely manner ( i. e., not later than the promulgation of the MACT standards). Third, these final MACT source categories were included in the " 10 year bin" because they were considered to be the lowest risk source categories. Finally, the risk based provisions are not available for standards that have already been implemented, and any decisions regarding risk must,

therefore, be applied on a source category specific basis.

We do not agree that changes to existing law are necessary because of the discretion provided to the Administrator under section 112( d)( 1) to distinguish among classes,

types, and sizes of sources within a category. We consider low risk facilities to be a class of sources within the PCWP source category.

Comment: Several commenters stated that the risk 85 based exemption proposal removes the " level playing field"

that would result from the proper implementation of technology based MACT standards. According to the commenters, establishing a baseline level of control is essential to prevent industry from moving to areas of the country that have the least stringent air toxics programs,

which was one of the primary goals of developing a uniform national air toxics program under section 112 of the 1990 CAA amendments. The commenters argued that risk based approaches would jeopardize future reductions of HAP in a uniform and consistent manner across the nation. One commenter stated that National Air Toxics Assessment ( NATA) data show that virtually no area of the country has escaped measurable concentrations of toxic air pollution.

The NATA information indicates that exposure to air toxics is high in both densely populated and remote rural areas.

One commenter disagreed with the assertion that the level playing field would be removed. The commenter pointed out that the argument that EPA should impose unnecessary and potentially environmentally damaging controls for the sole purpose of equalizing control costs across facilities would be at odds with the stated purpose of the CAA. According to the commenter, the claim that 86 the risk based approach would favor facilities located away from population centers is incorrect. As contemplated, the risk based approaches to the NESHAP would be keyed to the comparison of health benchmarks with potential maximum exposure, regardless of whether actual receptors are present at the exposure location. According to the commenter, the presence or absence of human populations would have no effect on whether facilities would qualify.

Response: We agree that one of the primary goals of developing a uniform national air toxics program under section 112 of the 1990 CAA amendments was to establish a level playing field. We do not believe that defining a low risk subcategory in today's final PCWP rule does anything to remove the level playing field for PCWP facilities. Today's final PCWP rule and its criteria for demonstrating eligibility for the delisted low risk subcategory apply uniformly to all PCWP facilities across the nation. Today's final PCWP rule establishes a baseline level of emission reduction or a baseline level of risk ( for the low risk subcategory). All PCWP facilities are subject to these same baseline levels, and all facilities have the same opportunity to demonstrate 87 that they are part of the delisted low risk subcategory.

The criteria for the low risk subcategory are not dependent on local air toxics programs. Therefore,

concerns regarding facilities moving to areas of the country with less stringent air toxics programs should be alleviated.

Although NATA may show measurable concentrations of toxic air pollution across the country, these data do not suggest that facilities that do not contribute to the high exposures and risk should be included in regulations. A discussion is provided elsewhere in this section regarding how background concentrations are accounted for by facilities demonstrating eligibility for the delisted lowrisk subcategory.

Comment: One commenter stated that the dockets for the MACT proposals that contain the risk approaches make it clear that the White House Office of Management and Budget ( OMB) and industry were the driving forces behind the appearance of these unlawful approaches in EPA's proposals. The commenter cited internal e mails between the White House OMB and EPA that reveal OMB officials exerting pressure on EPA to " take ownership" of the deregulatory approaches developed by industry. The 88 commenter noted that comparison of the proposal language for the Brick and Structural Clay Products ( BSCP) rule and PCWP rule makes it clear that EPA capitulated to OMB pressure to remove references to the risk based exemptions in the PCWP proposal preamble as being " industry's suggested approaches." The commenter cited preamble edits from OMB that the commenter believes reveals an OMB agenda to dictate EPA adoption of industry's risk based approaches, and to signal these plans in the rulemaking proposals, even before public comment has been taken. The commenter also noted that OMB urged support of a dangerous and technically unfounded HI of 10.0. The commenter condemned the industry driven agenda that is being promoted by the White House OMB.

A second commenter stated that the accusations that EPA succumbed to industry lobbying and internal pressures are entirely unfounded. The commenter stated that riskbased approaches are warranted because EPA's NESHAP program has now turned to the low risk source categories that Congress instructed EPA to address last. The commenter pointed out that 80 source categories have already been addressed with MACT standards. According to the commenter, the remaining source categories are lower 89 priority and include a large number of facilities that pose negligible risk to public health and environment.

The commenter stated that EPA purposefully saved those categories for last in accordance with Congress' explicit,

risk based priority setting mandate expressed in section 112( e)( 2). The commenter concluded that EPA has now reached the point where regulation by MACT would result in more environmental harm than good.

Response: The first commenter is correct in stating that industry representatives and OMB support the inclusion of risk based approaches in today's final PCWP rule as a method of reducing costs. We are required by Executive Order 12866 to submit to OMB for review all proposed and final rulemaking packages that would have an annual effect on the economy of $ 100 million or more. The comments we received from OMB reflect their position.

b. Effects on MACT program Comment: Several commenters expressed concern about the impact of a risk based approach on the MACT program.

Some commenters stated that the proposal to include riskbased exemptions is contrary to the 1990 CAA Amendments,

which calls for MACT standards based on technology rather than risk as a first step. The commenters pointed out 90 that Congress incorporated the residual risk program under section 112( f) to follow the MACT standards, not to replace them. One commenter added that risk based approaches would be used separately to augment and improve technology based standards that do not adequately provide protection to the public.

Another commenter believed that section 112( b)( 4) and the regulatory precedent established in over 80 MACT standards reject the inclusion of risk in the first phase of the MACT standards process. The commenter argued that the use of risk assessment at this stage of the MACT program is, in fact, directly opposed to Title III of the CAA.

Response: We disagree that inclusion of a low risk subcategory in today's final PCWP rule is contrary to the 1990 CAA Amendments. The PCWP rule is a technology based standard developed using the procedures dictated by section 112 of the CAA. The only difference between today's final PCWP rule and other MACT rules is that we used our discretion under CAA sections 112( c)( 1) and ( 9)

to subcategorize low risk facilities. The CAA requires that categories or subcategories meet specific risk criteria, and to determine this, risk analyses may be 91 used. We disagree with the commenter that we must wait for implementation of CAA section 112( f) before utilizing risk analysis in this manner. We believe that today's final PCWP rule is particularly well suited for a riskbased option because of the specific pollutants that are emitted. For many facilities, the pollutants are emitted in amounts that do not pose a significant risk to the surrounding population. However, the cost of controlling these pollutants is high, and may not be justified by environmental benefits for these low risk facilities.

Only those PCWP facilities that demonstrate that they are low risk are eligible for inclusion in the delisted lowrisk subcategory. The criteria included in today's final PCWP rule defining the delisted low risk subcategory are based on sufficient information to develop healthprotective estimates of risk and will provide ample protection of human health and the environment.

Inclusion of a low risk subcategory in today's final PCWP rule does not alter the MACT program or affect the schedule for promulgation of the remaining MACT standards.

We recognize that such provisions are only appropriate for certain source categories, and our decision making process required source category specific input from stakeholders. 92 The 10 year MACT standards, which are now being completed,

are the last group of MACT standards currently planned for development, and for any risk provisions to be useful, the provisions must be finalized in a timely manner ( i. e., not later than the promulgation of the MACT standards). These final MACT source categories were included in the " 10 year bin" because they were considered to be the lowest risk source categories.

Comment: Several commenters stated that the inclusion of a risk based approach would delay the MACT program and/ or promulgation of the PCWP MACT standard.

Commenters stated that the proposal to allow risk based exemptions would divert back to the time consuming NESHAP development process that existed prior to the 1990 CAA Amendments. Under this process, which began with a risk assessment step, only eight NESHAP were promulgated during a 20 year period. If the proposed approaches are inserted into upcoming standards, the commenters feared the MACT program ( which is already far behind schedule) would be further delayed.

One commenter stated that they were strongly opposed to returning to the morass of risk based analysis in an attempt to preempt the application of technology based 93 MACT standards and exempt facilities. The commenter stated that designing a risk based analysis procedure would also take significant resources, as evidenced by the fact that it took five plus pages in the Federal Register to discuss just the basic issues to be considered in the analysis. The commenter indicated that the demand on government resources could cause a delay in the application of MACT nationwide. The commenter stated that EPA should also consider the issue of fairness since the rest of the industrial sector whose NESHAP have already been promulgated did not have a risk based option.

Another commenter stated that it is evident that the proposed risk based exemptions would require extensive debate and review in order to launch, which would further delay promulgation of the remaining MACT standards. The commenter stated that delays could be exacerbated by litigation following legal challenges to the rules, and such delays would trigger the section 112( j) MACT hammer provision, which would unnecessarily burden the State and local agencies and the industries. The commenter concluded that, obviously, further delay is unacceptable.

Another commenter agreed, stating that it is imperative that EPA meet the new deadlines for promulgating the final 94 MACT standards.

Two commenters stated that EPA's proposal to improperly incorporate risk assessment into the technology based standard process would cripple a MACT program already in disarray. The commenters argued that the risk based approach could exacerbate the delay in HAP emissions reductions required by section 112. One commenter noted that EPA's Office of Inspector General recently found that EPA is nearly 2 years behind in fulfilling its statutory responsibilities for implementing Phase 1 MACT standards. According to the commenter, this delay potentially harms the public and environment. The inclusion of risk based exemptions in 10 year MACT standards would only further delay this process. The other commenter noted that EPA lacks adequate emissions and exposure data, source characterization data, and health and ecological effects information to conduct this process anyway. This commenter believed that the air toxics program is flawed and failing to protect public health and the environment and argued that it was irresponsible for EPA to pursue a deregulatory agenda that would further weaken the effectiveness of the air toxics program. The commenter noted that EPA acknowledged the 95 complexity and delays associated with the proposed riskbased approaches in deciding not to adopt the approaches in the final BSCP rule.

Response: We disagree that identification and delisting of a low risk subcategory in today's final PCWP rule will alter the MACT program or affect the schedule for promulgation of the remaining MACT standards. We do not anticipate any further delays in completing the remaining MACT standards. The delisting of a low risk subcategory in today's final PCWP rule affects only the PCWP rule, and not all other MACT standards that have yet to be promulgated.

We believe that the PCWP rule is particularly wellsuited for a risk based option because of the specific pollutants that are emitted. For many facilities, the pollutants are emitted in amounts that do not pose a significant risk to the surrounding population. However,

the cost of controlling these pollutants is high and may not be justified by environmental benefits for these lowrisk facilities. Only those PCWP facilities that demonstrate that they are low risk are eligible for inclusion in the delisted low risk subcategory. The criteria defining the delisted low risk subcategory are 96 based on sufficient information to develop healthprotective estimates of risk and will provide ample protection of human health and the environment.

Delisting of a low risk subcategory of PCWP facilities does not mean that we will provide risk based options for other industries. Furthermore, we have no intentions of reopening previously promulgated NESHAP in light of decisions made specific to the PCWP source category. The PCWP NESHAP is being promulgated by the February 2004 court ordered deadline. Any delays in implementation of the PCWP NESHAP caused by legal challenges are beyond our control.

2. Legal authority a. Section 112( d)( 4)

Comment: We received multiple comments stating that section 112( d)( 4) provides EPA with authority to exclude sources that emit threshold pollutants from regulation.

The commenters cited the language in section 112( d)( 4) and CAA legislative history. The commenters pointed out that EPA exercised its section 112( d)( 4) authority previously in choosing not to impose control requirements on hydrogen chloride ( HCl) emissions from chemical recovery furnaces at pulp mills ( 40 CFR Part 63, Subpart MM, See 63 FR 97 18754, 18765 ( April 15, 1998)).

We also received multiple comments disagreeing that section 112( d)( 4) can be interpreted to allow exemptions for individual sources. The commenters argued that section 112( d)( 4) applies only to categories or subcategories of sources and not to individual sources.

These commenters also cited the language of section 112( d)( 4) and CAA legislative history. The commenters interpreted section 112( d)( 4) to state that health based thresholds can be considered when establishing the degree of the MACT floor requirements, but they should not be used in lieu of the requirements established pursuant to section 112( d)( 3). One commenter also argued that the third scenario suggested by EPA   application of section 112( d)( 4) exemption to emission points within a facility   is unlawful because there is no statutory provision within the CAA to authorize emission point by point exemption.

Several commenters supported the use of section 112( d)( 4) applicability cutoffs for both threshold and non threshold pollutants and believe that a health threshold of one in a million cancer risk is appropriate for non threshold pollutants. The commenters interpreted the language in section 112( d)( 4) to mean EPA may issue 98 standards for any pollutant for which a threshold may be established. The commenters believe that EPA could use its section 112( d)( 4) authority to establish a " threshold"

risk of one in a million for non threshold carcinogens.

The commenters also believe that section 112( d)( 4) may be properly applied to carcinogenic HAP that EPA determines have a threshold of safe exposure. The commenters noted that the current health science for formaldehyde and aceteladehyde shows that these two HAP are threshold carcinogens that are emitted from wood products facilities at levels that will not pose a significant risk to human health.

Multiple other commenters stated that section 112( d)( 4) does not apply for source categories that emit carcinogens. The commenters argued that EPA may only use the section 112( d)( 4) authority for pollutants with a well established health threshold. The commenters stated that section 112( d)( 4) only allows EPA to substitute a health threshold for a MACT standard when the threshold " has been established." The commenters contended that Congress did not intend for EPA to spend time determining if a threshold exists and that it was Congress' intent that EPA have a high degree of scientific certainty before 99 using its section 112( d)( 4) authority. The commenters cited legislative history. ( See S. Rep. 101 228 at 171.)

The commenters also stated that Congress specified that EPA must have direct evidence of no effects, i. e., use of a no observable effects level ( NOEL), before invoking section 112( d)( 4); thus, EPA must be sure that there are no effects from exposure at the level chosen for the emission standard. The commenters further argued that all carcinogens must be treated as non threshold pollutants and noted that the history of the 1990 CAA Amendments shows that Congress legislated with an understanding that carcinogens do not have a safe threshold.

Response: We acknowledge the commenters' arguments regarding our discussion in the PCWP proposal preamble regarding potential applicability cutoffs for threshold pollutants under the authority of section 112( d)( 4) of the CAA. We believe that section 112( d)( 4) does not give us the authority to exempt facilities or emission points from MACT limitations on non threshold pollutant emissions.

All PCWP facilities emit carcinogens ( e. g., formaldehyde),

which are currently considered non threshold pollutants.

Therefore, we are not using section 112( d)( 4) authority to create risk based options for PCWP. We do not expect to 100 further explore the use of section 112( d)( 4) of the CAA to exempt PCWP facilities from the MACT floor on a case

bycase basis or to set alternative standards, because PCWP facilities emit HAP for which no health thresholds have been established and because the legislative history to the 1990 Amendments to the CAA indicates that Congress considered and rejected allowing us to grant such sourcespecific exemptions from the MACT floor. ( See, e. g., 1 Legis. Hist. at 866, 877; 2 Legis. Hist. at 2141 42,

3939.) As discussed below, we are establishing and delisting a subcategory of low risk PCWP facilities using our authority under CAA sections 112( c)( 1) and ( 9).

We are establishing criteria in today's final PCWP rule that define a low risk subcategory of PCWP facilities, which requires demonstration that a facility warrants being included in this subcategory. The criteria are not included in the rule as " emission standards" or " emission limits" but are included in an appendix to the rule that specifies how facilities must make their lowrisk demonstrations and the steps that facilities must take to ensure that they remain in the low risk subcategory. We are not setting a risk based emission limit, but, rather, we are using our section 112( c)( 9) 101 authority to delist facilities that demonstrate they meet the risk and hazard criteria for being included in this low risk subcategory.

b. De minimis Comment: Some commenters attempted to identify a source of authority for risk based approaches that was not discussed in the preamble to the proposed rule. The commenters stated that a risk based compliance option for both threshold and non threshold HAP is well within EPA's authority under the CAA and the de minimis doctrine articulated by appellate courts. The commenters cited appellate case law which they believe makes it clear that EPA may lawfully exempt de minimis sources of risk from MACT level controls because the legislative mandate of section 112 is not " extraordinarily rigid" and the exemption is consistent with the CAA's health protective purpose. The commenters also noted that sections 112( c)( 9) and 112( f)( 2) indicate that Congress considered a cancer risk below one in a million to be de minimis and therefore insufficient to justify regulation under section 112. The commenters stated that ( and cited examples where) EPA's exercise of de minimis authority has withstood judicial challenge, and that application of de 102 minimis authority ( as well as its treatment by reviewing courts) is based on the degree of risk at issue, not on the mass of emissions to be regulated. The commenters stated that the D. C. Circuit has invalidated EPA's de minimis authority only where it was applied under statutory designs that are " extraordinarily rigid." The commenters stated that section 112 provides clear indication of Congressional intent as to the degree of risk that properly is to be considered de minimis. A cancer risk of one in a million triggers further review under the " residual" risk provision of section 112( f), and a one in a million cancer risk is the threshold below which EPA is authorized under section 112( c)( 9)( B) to remove source categories from MACT regulation. One commenter attached a paper they developed entitled " Legal and Policy Basis for EPA's Exercise of Its De minimis Authority Under Section 112 of the Clean Air Act in the Context of the Wood Products MACT."

Other commenters argued that de minimis authority does not exist to create MACT exemptions on a facility

byfacility or category wide basis. In addition, the commenters stated that EPA lacks de minimis authority to delist subcategories based on risk. The commenters cited 103 case law and stated that EPA may not rely on its narrow de minimis exemption authority to escape the highly prescriptive provisions in section 112. The commenters further noted that EPA has not revealed any administrative record justifying a de minimis exemption, to demonstrate in any way that compliance with MACT would " yield a gain of trivial or no value."

Response: We disagree with the commenters who claimed that the low risk approaches, especially the concentration based exemption, can be justified by de minimis principles. Our de minimis authority exists to help avoid excessive regulation of tiny amounts of pollutants, where regulation would yield a result contrary to a primary legislative goal. It is unavailable " where the regulatory function does provide benefits, in the sense of furthering the regulatory objectives, but the agency concludes that the acknowledged benefits are exceeded by the costs." EDF v. EPA, 82 F. 3d 451, 466 ( D. C. Cir. 1996); Public Citizen v. Young, 831 F. 2d 1108,

1112 13 ( D. C. Cir. 1987); Alabama Power v. EPA, 636 F. 2d 323, 360 61 & n. 89 ( D. C. Cir. 1979). Accordingly, a de minimis exemption to section 112( d)( 3) is unavailable in today's final PCWP rule because it would frustrate a 104 primary legislative goal by preventing application of the MACT floor to tons of PCWP facilities' HAP emissions.

The U. S. Court of Appeals for the District of Columbia Circuit has already addressed the de minimis concept in the MACT context, in National Lime Ass'n v.

EPA, 233 F. 3d 625, 640 ( D. C. Cir. 2000) ( National Lime),

in which the court rejected the industry petitioner's claim that, in light of both the high costs and low quantities of HAP at issue in that case, we should read a de minimis exception into the requirement that it regulate all HAP emitted by major sources. In that case, the Court found that " EPA reasonably rejected this argument on the ground that the statute ` does not provide for exceptions from emissions standards based on de minimis principles where a MACT floor exists.'" ( See National Lime at 640.)

We recently re affirmed our position on the unavailability of de minimis exemptions from the MACT floor in the final rule regulating organic liquids distribution. ( See 69 FR 5038 ( February 3, 2004).)

We see no reason to revisit this fundamental issue.

Section 112 of the CAA is replete with careful definitions of volume or effect based limitation on regulation,

indicating that Congress has already defined what amounts 105 of HAP emissions are too small to warrant MACT standards or other controls under section 112. The requirement to adopt MACT emission limitations, for example, applies without exception to " each category or subcategory of major sources... of [ HAP]." ( See CAA section 112( d)( 1).)

For sources below the major source threshold, however, we have discretion to require " generally available control technologies or management practices." ( See CAA section 112( d)( 5).) Congress has, thus, itself defined volumetrically which sources' emissions are small enough not to warrant mandatory MACT standards.

Congress likewise defined several MACT exceptions applicable where emissions have de minimis health effects.

Section 112( d)( 4) of the CAA allows us to establish standards less stringent than MACT for HAP with an established health threshold, so long as we set a standard below the health threshold with " an ample margin of safety." Section 112( b)( 3)( C) of the CAA directs us to delist HAP   precluding section 112( d) MACT standards   if we determine that " there is adequate data on the health and environmental effects of the substance to determine that emissions, ambient concentrations, bioaccumulation or deposition of the substance may not reasonably be 106 anticipated to cause any adverse effects to the [ sic]

human health or adverse environmental effects." Section 112( c)( 9)( B)( i) of the CAA ( discussed further below) lets us delete source categories and subcategories from the category list   the consequence again being no MACT control   if we determine that, for emissions of carcinogenic HAP,

" no source in the category... emits such [ HAP] in quantities which may cause a lifetime risk of cancer greater than one in one million to the individual in the population who is most exposed to emissions of such pollutant from the source." For noncarcinogens, we may delete source categories and subcategories if we determine that " emissions from no source in the category or subcategory... exceed a level which is adequate to protect public health with an ample margin of safety and no adverse environmental effect will result from emissions from any source." ( See CAA section 112( c)( 9)( B)( ii).)

Moreover, in defining which source modifications trigger additional regulatory standards, CAA section 112( g)( 1)( A)

mentions a " greater than de minimis increase in actual emission of a [ HAP]." This shows that Congress knew how to use the de minimis concept when it considered it appropriate in section 112, and the fact that Congress did 107 not use it in section 112( d)( 3) supports our   and the D. C. Circuit's   conclusion that it is unavailable to support an exception to a MACT floor that is not otherwise authorized under section 112.

We do not find persuasive the proposition that the overall purpose of section 112 is protecting human health and the environment, and that, therefore, as long as this general purpose is met, we may fashion de minimis exceptions from MACT beyond those allowed under section 112. First, this position appears to assume that the issue is to be drawn on a clean slate, while the D. C.

Circuit has affirmed our view that section 112( d)( 3)

provides no discretion to use a de minimis rationale to avoid MACT. Second, the commenter appears to give prominence to an over arching statutory goal over the specific language of the statutory provisions themselves,

in assessing whether those provisions are " extraordinarily rigid" regarding EPA's otherwise inherent de minimis authority; the logical extension of such an approach would be to find that no single provision in the CAA could restrict our de minimis authority, in light of the CAA's over arching purpose " to promote the public health and welfare." ( See CAA section 101( b)( 1).) Third, the 108 commenter does not present any persuasive statutory arguments to overcome those that we presented to the court   and which the court affirmed   in National Lime.

Fourth, we are unable to discern the basis for the commenter's suggestion that we have in fact been relying on de minimis authority in the MACT program for several years in establishing applicability thresholds, and we are not aware of any instance in which we have explicitly justified an exception from an applicable MACT floor based on a de minimis rationale that would be, like the commenter's requested exemption, in contravention of the Court's ruling in NLA. Finally, to the extent the commenters believe such a de minimis exemption is justified by the wish to reduce the costs of the PCWP rule, we are not free to grant a de minimis exemption to account for costs. Congress already took cost into account in section 112( d), relying on prior business judgments by the best performing sources to substitute for the judgment of the rest of the PCWP industry, therefore,

denying us the leeway to consider costs as a factor to modify the MACT floor. Only in considering more stringent " beyond floor" standards may we consider costs in the MACT context. Therefore, we do not believe it is appropriate 109 or necessary to revisit our and the D. C. Circuit's prior conclusions regarding the availability of the de minimis principle in today's final PCWP rule.

c. Section 112( c)( 9)

Comment: Two commenters opposed using subcategorization as a mechanism to exempt facilities.

One of the commenters stated that subcategorization is a tool that should be used in the standard setting process,

and using it to exempt facilities would have a detrimental effect on the stringency of the MACT floor and would generally degrade the standard. According to the commenter, the two step subcategorization proposal is inconsistent with how subcategorization has been done in numerous previous NESHAP.

The other commenter argued that EPA's subcategorization theories are unlawful. According to the commenter, section 112( c)( 9) does not authorize EPA to separate identical pollution sources into subcategories that are regulated differently to weed out low risk facilities or reduce the scope/ cost of the standard. The commenter stated that subcategories based solely on risk do not bear a reasonable relationship to Congress'

technology based approach or the statutory structure and 110 purposes of section 112, and are not authorized by the CAA. According to the commenter, categories and subcategories are required to be consistent with the categories of stationary sources in section 111. The commenter was not aware of any instance in which EPA has established categories or subcategories based on risk.

The commenter stated that EPA routinely defines subcategories based on equipment characteristics ( e. g.,

technical differences in emissions characteristics,

processes, control device applicability, or opportunities for pollution prevention). According to the commenter,

EPA has not offered any explaination for why reinterpreting the statute to ignore nearly 12 years of settled practices and expectations under the MACT program is reasonable, nor why reducing the applicability of HAP emission standards serves Congress's goals in enacting the 1990 CAA Amendments.