Risk Assessment and the Air Toxics Program

1. Risk Assessment and the Air Toxics Program Kenneth Mitchell, Ph.D.; Chief Air Toxics Program U.S. Environmental Protection Agency Atlanta, GA

2. For today…. • Air Toxics….a quick review • The use of risk-based principles in section 112 of the Clean Air Act (the “air toxics” section) • The “Integrated ‘Urban’ Air Toxics Strategy” • Residual Risk • The Air Toxics Risk Assessment (ATRA) Reference Library

3. Six“Criteria” Pollutants O3, NO2, SO2, Pb CO, PM Mobile Source Pollutants 21 Chemicals & Mixtures The Federal Clean Air Act Hazardous Air Pollutants (Air Toxics) 187 Chemicals & Compounds What do we mean by “Air Toxics?”

4. There Are Sources Everywhere! Courtesy of Sustaining the Environment and Resources for Canadians

5. Types of Sources Major Sources 10 TPY or more of one HAP Or 25 TPY or more of a combination of HAPS Area Sources Less than 10 TPY of one HAP Or Less than 25 TPY of a combination of HAPS

6. Types of Sources Outdoor Air Indoor Sources Not regulated but pose (on average) 3-5 times the concentrations of outdoor air Mobile Sources On- and Off-road; Engines, fuels, and operation all contribute to pollution; 21 MSATs

7. Risk in CAA section 112 • The concept of “risk” plays an important role in several parts of Section 112 • Two notable examples are: • §112(k) – “The Area Source Program” (the Integrated Air Toxics Strategy) • §112(f) – “Standard to Protect Health and the Environment” (the residual risk program)

8. Some notable examples A quick reminder… What’s the role of risk in CAA Sec 112? Human health risk assessment is the process of using the factual base of information to estimate the potential for health effects in individuals or populations exposed to hazardous materials and situations. Adapted from NAS, 1983

9. WIND DIRECTION A B BIOACCUMULATION IN FOOD TRANSFORMATION WET DEPOSITION DISPERSION DRY DEPOSITION EVAPORATION/REENTRAINMENT IN AIR CANCER TARGET ORGAN/TISSUE INGESTION DERMAL INHALATION NON-CANCER ENDPOINTS EXCRETION INTAKE/UPTAKE

10. EPA’s Integrated Air Toxics Strategy • EPA published it’s Integrated “Urban” Air Toxics Strategy in July of 1999 (now just the Integrated Air Toxics Strategy) • Four key components • Regulations addressing air toxics sources (e.g., “area source” standards) • Initiatives to address specific pollutants (e.g., mercury) and to identify and address specific community risks • Air toxics assessments (including expanded air toxics monitoring and modeling) to identify areas of concern, prioritize efforts, and to track progress (e.g., NATA) • Education and outreach

11. EPA’s Integrated Air Toxics Strategy • Three Main Goals • Reduce by 75% the risk of cancer associated with air toxics from both large and small stationary sources • Substantially reduce noncancer health risks associated with air toxics from both large and small stationary sources; and • Address disproportionate impacts of air toxics across urban areas, such as “hot spots” and low-income communities

12. Residual Risk Program • Assess remaining (or “residual”) risks from stationary sources that emit air toxics after technology-based (MACT) standards are in place • Set additional standards if MACT does not protect public health with an “ample margin of safety” • Set additional standards if necessary to prevent adverse environmental effects

13. What is the focus of a RR analysis? Long Range Pollutant Transport These Emissions These Risks Facility Boundary Colocated Facility Source Regulated MACT Source Nearby Off-site Sources Nearby Residential Exposures 11.b 14

14. Benzene NESHAP Decision Process • Step 1: determine “acceptable risk” considering all health information, including uncertainty, to the Maximum Individual Risk (MIR) • Ordinarily about 100 in a million (1E-04) • An acceptable MIR may be more or less than 1E-04, depending on incidence, health endpoint, number of persons within various risk ranges, and uncertainties • Incidence should not be limited to, for example, 1 case/year, but rather weighed along with other risk information • Step 2: set standard to provide “ample margin of safety”, considering health information and other relevant factors (costs, feasibility) • Protect the greatest number of persons possible to approximately 1 in a million lifetime cancer risk or lower

15. Highest Actual Exposure to a Real Person? Smallville Pop. 4000 Farm Boundary SMALLVILLE National Forest Census Block Internal Points? Highest Off-Site Concentration? + Census Tract Internal Point? Census Tract Boundary Closest Monitoring Site? What can we use to represent exposure? = Facility Boundary

16. Ample Margin of Risk Unsafe Safety with Ample Margin consideration of Action Needed to of Safety Met costs, technical Reduce Risks feasibility and other factors -6 -4 10 10 MIR Relevant Cancer Risk Range

17. Ample Margin of Risk Unsafe Safety with Ample Margin consideration of Action Needed to of Safety Met costs, technical Reduce Risks feasibility and other factors 1.0 case-by-case HImax Relevant Non-Cancer Hazard Range

18. Available at: http://www.epa.gov/ttn/fera/risk_atra_main.html New Risk Assessment Guidance from EPA EPA’s new Air Toxics Risk Assessment (ATRA) Reference Library describes the basics of exposure assessment, toxicity evaluation, and risk characterization (chronic and acute) for toxic pollutants released to the air from stationary, mobile, and other types of sources. The library covers both human and ecological assessment for individual sources of pollution as well as the combined impact of multiple sources. This guidance is amenable to a variety of purposes, including assessments conducted under the air toxics provisions of the Clean Air Act, analysis of combined multisource risks at the community level, and as a supplement to other Agency guidance (e.g., as an aid to Superfund risk assessors evaluating the air exposure pathway).

19. If we have time… Some updates….

20. Area Sources – Current Status • The Integrated Urban Strategy was published July 19, 1999 • Identified chemicals of concern • Identified initial list of area source categories • 70 source categories have been listed • Listing completed in November 2002 • Source categories required to be “subject to regulation” • 16 rules completed • 4 under court order 20 of the 70 Standards

21. Area Sources – Recent Court Order • Dec. 15, 2006 4 categories • June 15, 2007 6 categories • Dec. 15 2007* 10 categories • June 15, 2008 10 categories • Dec. 15, 2008 10 categories • June 15, 2009 10 categories 50 Categories *3 area source standards subject to CAA 112(c)(6) (related to PBT chemicals) must be promulgated by this date.

22. Area Sources – Possible Future Directions • Several approaches being considered to minimize the number of rules to be developed: • One rule covering one source category • Rules covering combined categories • fabricated plate work covering 8 categories • Performance-based approach • flexible approach for sources and implementing authority • Other resource saving approaches • Notice of findings where rules are not needed • Notice that there is a need for a regulatory mechanism but one is already in place

23. Residual Risk Status (Promulgation Dates) • Coke ovens – April 2005 • March 2006 • Industrial cooling towers • Magnetic tape • Ethylene oxide sterilizers • Gasoline distribution • Dry cleaning – July 2006 • HON – December 2006 • Halogenated Solvents – December 2006

24. Residual Risk – Possible New Directions • Develop clustered “Risk and Technology Review (RTR)” rulemakings • Phased approach based on availability of emissions data • A “Total Facility Low-risk Demonstration (TFLRD)” rule option may also be made available as part of the RTR rulemakings

25. Mobile Source Air Toxics (MSATs) • In March 2001, EPA published first MSAT rule • Toxics emissions performance standard for gasoline • Refinery-specific baselines to ensure no backsliding from 1998-2000 performance • No additional standards for fuels or vehicles • Identified data gaps and committed to additional research • Committed to additional rulemaking to evaluate the need for and feasibility of additional controls

26. MSATs – Future Directions • Proposed Rule in the Federal Register on March 29, 2006 • Public hearing on April 12 • 60-day comment period (through May 30th) • Final rule by February 9, 2007

27. MSATs – Future Directions • Benzene content standard for gasoline • Vehicle standards • Exhaust emissions • Evaporative emissions • Gas can standards

28. Diesel Exhaust – Current/Future Directions • Building on the successes of EPA’s regulatory and voluntary efforts to reduce emissions from diesel engines, EPA has created the National Clean Diesel Campaign (NCDC) • Successful implementation of the 2007 Highway Engine Rule and the Clean Air Nonroad Diesel Rule • Develop new emissions standards for locomotive and marine diesel engines • Promote reduction of emissions for existing diesel engines through cost-effective and innovative strategies, including use of cleaner fuels, retrofitting and repairing existing fleets, idling reduction among others • Southeast Diesel Collaborative

29. Community-based Approaches • A variety of approaches and tools to assess and address air toxics at the local level are in progress • Air toxics monitoring grants • Community Action for a Renewed Environment (CARE) Program • Other state/local studies • ATRA Library, Volume 3 • Etc.

30. Thanks for your attention! Ken Mitchell U.S. Environmental Protection Agency (404) 562-9065 mitchell.ken@epa.gov http://www.epa.gov/region4/air/airtoxic/index.htm