1. Toxicology Update - Implementation of Revised Impacts Review Procedures Mike Coldiron, P.E. Air Permits Division Texas Commission on Environmental Quality Advanced Air Permitting Seminar 2015

2. Revisions to Review Procedures Revisions to Review Procedures o Procedural changes to impacts review were designed to reduce processing times o Fewer projects will need review by the Toxicology Division (TD) o Fewer ESLs will need to be derived

3. Revisions to Review Procedures Revisions to Review Procedures o Case-by-case de minimis review will no longer require TD review o For projects that meet the Tier II TD requirements, no TD review is needed o Fewer particulate species will need a TD review

4. Revisions to Review Procedures Revisions to Review Procedures De Minimis Toxicological Tiered Reviews Particulate Matter

5. De Minimis Review Procedures Revisions to Review Procedures De Minimis

6. Revisions to Review Procedures De Minimis De Minimis Review Procedures Case-by-case reviews no longer require TD approval and may be completed by the permit reviewer if: o Modeled emissions rates are the rates without the use of emission controls; o Impacts are evaluated using SCREEN3 only;

7. Revisions to Review Procedures De Minimis De Minimis Review Procedures o The maximum off-property impacts are less than 10% of ESL for individual species; and o The impacts for criteria pollutants are less than the SIL for all averaging periods

8. Current Toxicological Tiered Permit Reviews Revisions to Review Procedures Toxicological Tiered Reviews

9. Current Toxicological Tiered Permit Reviews Toxicology Review Tier Review CriteriaResponsibility for Review Tier IAll impacts are below ESLsAPD Tier II Impacts on non-industrial receptors < ESL, Impacts on industrial receptors < 2X ESL Toxicology Tier IIICase-by-case reviewToxicology

10. Revised Toxicological Reviews Tier II Toxicology Review Tier Review CriteriaResponsibility for Review Tier IAll impacts are below ESLsAPD Tier II Impacts on non-industrial receptors < ESL, Impacts on industrial receptors < 2X ESL APD Tier IIICase-by-case reviewToxicology

11. Current Particulate Matter Review Procedures Revisions to Review Procedures Particulate Matter

12. Revisions to Review Procedures Particulate Matter Current Particulate Matter Review Procedures o Over 4,000 species on the ESL List, but many more species in the world o TD receives frequent requests for ESLs for PM species o An ESL must be developed for each species not on the current ESL List

13. Revisions to Review Procedures Particulate Matter Current Particulate Matter Review Procedures o ESL development is time consuming, and applicants can wait two weeks or more for a response o Many species are of limited concern o Species of concern include metals and certain silica compounds

14. Revisions to Review Procedures Particulate Matter Revised Particulate Matter Review Procedures o For species of limited concern, no additional review is required, as long as compliance with the PM 2.5 NAAQS is demonstrated o For species of concern, use the current review procedures

15. Revisions to Review Procedures Particulate Matter Particulate Matter Species of Limited Concern o Changes to PM species procedures represent a new impacts analysis approach

16. Revisions to Review Procedures Particulate Matter Justification for Revised Procedures o New approach still protective of public health o Comparison of 24-hour NAAQS standard to equivalent 1-hour concentration

17. Justification for Revised Procedures Air Contaminant Averaging Period NAAQS (µg/m 3 ) 1-hr to 24-hr Conversion Factor Equivalent 1-hr Concentration (µg/m 3 ) PM 2.5 24-hr350.4087.5

18. Justification for Revised Procedures Air Contaminant Averaging Period Surrounding Land Use Example Background Concentration (µg/m 3 ) 1-hr to 24-hr Conversion Factor Equivalent 1-hr Concentration (µg/m 3 ) PM 2.5 24-hrIndustrial250.4062.5 PM 2.5 24-hrRural180.4045.0

19. Justification for Revised Procedures Air Contaminant Averaging Period Equivalent 1-hr Concentration (µg/m 3 ) Surrounding Land Use Example Background Concentration (µg/m 3 ) Equivalent 1-hr Allowable Total Site Concentration (µg/m 3 ) PM 2.5 1-hr87.5Industrial62.525.0 PM 2.5 1-hr87.5Rural45.042.5

20. Revisions to Review Procedures Particulate Matter Implementation of Revised PM Review Procedures o Identification of all species and species emission rate calculations are still required o For species of limited concern, no further species- specific analysis is required o An appropriate PM 2.5 NAAQS analysis is required

21. Revisions to Review Procedures Particulate Matter Implementation of Revised PM Review Procedures o For all other species, the impacts analysis remains unchanged o Even if the analysis is completed using the MERA flowchart, modeling may still be required to support the chemical flexibility condition

22. Permit Condition Revisions o Current chemical flexibility special condition requires an ESL for each species o The special condition has been revised to accommodate the revised impacts analysis o No exceedance of the PM 2.5 NAAQS is allowed

23. Revised Procedure Exclusions o Contested case hearings o Public comments on exposure to air contaminants o Unsatisfactory compliance history rating o Emissions of an APWL species in an APWL area

24. In Review Summary o Case-by-case de minimis review will no longer require TD review o For projects that meet the Tier II TD requirements, no TD review is needed

25. In Review Summary o Fewer particulate species will need a TD review, and a PM 2.5 NAAQS analysis will serve as a surrogate for these species o The revised procedures are not allowed in certain cases

26. In Review Websites Home Rules and Rulemaking Index of Common Permitted Facilities Effects Screening Levels Tables Forms BACT MERA Air Dispersion Modeling

27. Contact Information Phone Numbers APIRT: (512) 239-3075 APD: (512) 239-1240 or (512) 239-1250

28. Contact Information Mike Coldiron Contact Information Mike Coldiron, P.E. (512) 239-5027 mike.coldiron@tceq.texas.gov