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Air Toxics An Update. Kenneth L. Mitchell, Ph.D. U.S Environmental Protection Agency Atlanta, Georgia November 2005. The Air Toxics Risk Assessment Library. Air Toxics Guidance. ATRA Reference Library. Volume 1 : Technical Resource Manual (Complete)
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Air ToxicsAn Update Kenneth L. Mitchell, Ph.D. U.S Environmental Protection Agency Atlanta, Georgia November 2005
The Air Toxics Risk Assessment Library Air Toxics Guidance
ATRA Reference Library • Volume 1: Technical Resource Manual (Complete) • Volume 2: Facility-specific Assessment (Complete) • Volume 3: Community-Level Assessment (In Peer Review) www.epa.gov/ttn/fera
Air Toxics Monitoring Screening Guidance • Region 4’s A Preliminary Risk-Based Screening Approach for Air Toxics Monitoring Data Sets • Easy to perform • Provides (generally) conservative results • Helps to evaluate whether there is a potential problem that needs further evaluation • We are responding to last minute comments and hope to publish by the end of the year
The Area Source Program An Update
Area Sources • Potential to emit less than 10 tpy for a single HAP and less than 25 tpy for combined HAP • Individual area sources are small emitters • Many sources emit less than 100 pounds of HAPs • Collectively, these sources are important toxic contributors, especially in urban areas 1999 NEI
Statutory Requirements • 112(c)(3) and 112(k) • List area source categories representing at least 90% of the emissions of the 30 listed urban HAP • Prepare a national strategy for urban air toxics • Subject categories to regulation and promulgate by 11/15/2000 • Achieve at least a 75% reduction in cancer incidence
Listing of Categories • The Integrated Urban Strategy was published July 19, 1999 • 70 source categories have been listed • Listing completed in November 2002 • Source categories required to be “subject to regulation”
Status • 15 standards have been completed • 5 categories are under consent decree:
Status of Remaining 50 Categories • 28 source categories have been initiated • Based on a toxicity-weighted prioritization • 22 remain unaddressed • Schedule under litigation • Final oral arguments scheduled for November • Expect court schedule sometime after that
Program Challenges • There are numerous facilities • Many small businesses • Most sources have not been regulated before • Most sources are difficult to locate • Most are not included in existing inventories • Most are not required to report under Title III • Many are not represented by trade associations • There are smaller amounts of emissions per facility but collectively can present a problem
Program Challenges • Resources are limited • Need to balanceaddressing the requirements and the high risk areas with resources and practical restraints for implementation • Need to provide for states that need regs and states with existing programs • Need to maximize co-benefit reductions
Implementation Challenges • Many states don’t have resources to take delegation • EPA will have to implement program where states do not take delegation • Need to minimize burden for all levels -- especially small businesses
Exploring New Ways of Doing Business • Explore options to nontraditional rulemaking • Explore pollution prevention approaches • Develop user friendly and cost effective control options • Develop innovative compliance measures • Simplified monitoring plans, reduced recordkeeping, self-certification for permitting
Proposed Area Source Framework Screening/Characterization of Source Categories Step 1 - Binning or National Rulemaking Approach Flexible Rulemaking Approach Step 2 – Two Rulemaking Approaches 1 Source Category Rulemaking 1 Rule/ Multiple Categories Control Options Control Options Pollution Prevention Options Pollution Prevention Options
Two Regulatory Approaches • National Rulemaking Approach • Establish national standards for source categories that have a national level of concern • Flexible Rulemaking Approach • Enact a rule, covering a set of categories, that will regulate how categories are controlled at the local level based on local needs • EPA will provide guidance on control approaches
Focus on GACT • Can develop standards or requirements • 112(d)(5) – use of Generally Available Control Technologies or management practices • Advantages to using GACT: • Allows more flexibility • There is no floor to calculate • Cost effectiveness is considered
Potential Authorities • 112(k)(4) – encourage and support area wide strategies developed by state and locals • 112(l) – each State may develop and submit a program for implementation and enforcement • 301(a) – EPA can prescribe such regulations as are necessary to carry out its function under the Act.
Framework Status • Spring 2005 developed a white paper describing the concept and issues to be addressed • Summer 2005 created teams to help work on issues and develop implementation plan • Timeframe • By October 30 – completed implementation plan with details on how to implement framework • By December 30 – begin development of draft preamble language for flexible area source process rule
The Residual Risk Program An Update
Summary of Residual Risk Activities • Coke ovens rule promulgated 3/05 • Tightened standards moderately for a limited number of facilities • Set forth several general policies, principles; e.g., • Reinforced use of 2-step decision process: first determine acceptability, then ample margin of safety • Total facility risks could be considered in ample margin of safety determinations, not acceptability determinations • Intent to provide multiple risk metrics, move toward probabilistic assessments, where appropriate • Intent to improve multipathway and ecological risk assessments
Summary of Residual Risk Activities (cont.) • Several proposals for no further action • Gasoline distribution • Risks low, but not below statutory trigger (1 in a million cancer risk) • Additional controls could reduce risk minimally • Cost of controls was exorbitant • Proposal issued 8/05 • Ethylene oxide sterilizers • Maximum cancer risks near upper limit of “acceptable” • Additional controls unfeasible; process provides health benefits • Proposal approved by OMB; publication soon
Summary of Residual Risk Activities (cont.) • Proposals of no further action (cont.) • Industrial process cooling towers • MACT rule banned use of chrome as corrosion inhibitor • Assessment determined that risks from all other HAP were below statutory trigger, residual risk rule unnecessary • Proposal approved by OMB, publication soon • Magnetic tape manufacturing • Assessment determined risks to be below trigger, residual risk rule unnecessary • Proposal approved by OMB, publication soon
Summary of Residual Risk Activities (cont.) • One proposal imminent • Perchlorethylene dry cleaners • Risks generally high, even for some smaller area sources • Risks unusually high for some “co-residential” area sources – based on limited monitoring • Proposal aims to improve levels of control for major and area sources • Considering banning future location of area sources in residential buildings • Proposal release targeted for October
Summary of Residual Risk Activities (cont.) • Two proposals on horizon • Hazardous organic chemical manufacturing (HON) • Maximum cancer risks near upper limit of “acceptable” • Additional controls feasible, minimal risk reduction, moderate costs • Currently weighing “ample margin of safety” options for proposal; targeted date for release, 2/06 • Halogenated solvent cleaners (a.k.a. degreasers) • Maximum cancer risks near upper limit of “acceptable” • Currently weighing “ample margin of safety” options for proposal; targeted date for release, 2/06
Summary of Residual Risk Activities (cont.) • Court-ordered deadlines for final rules • Gasoline distribution, ethylene oxide, cooling towers, magnetic tape due 3/06 • Dry cleaners due 4/06 • HON, Degreasers due 12/06
Reducing residual risk burden for low risk sources • May seek comment on allowing low-risk HON or Degreaser sources to demonstrate compliance via risk assessment • Assessment must show risks below target • Emission rates used for assessment must be included in permit as limits • Developing process rule for whole facilities (TFLRD) • Considering alternative process for entire program (GRRR)
Summary of the TFLRD Rule • Voluntary process option available to facilities with at least one MACT source category on site • Step 1 -- Source conducts a total facility risk assessment • Sources referred to EPA’s Air Toxics Risk Assessment Reference Library for risk assessment guidance • Step 2 -- If they meet low risk criteria defined in rule, source submits risk assessment to permitting authority • Low risk criteria: maximum cancer risk < 1E-06, all non-cancer TOSHI values < 1, all ecological HQ values < 1
Summary (Cont.) • Step 3 -- Review and approval: We are evaluating several options • Could involve EPA review, state review, 3rd party review, or source self-certification and audit review • Step 4 -- Parameters from low risk demonstration must then be incorporated into Title V permit • Parameters become enforceable permit limits • Facilities that successfully complete this process are deemed to be in compliance with any current or future relevant 112(f) requirements • Subsequent changes at facility would trigger re-evaluation
Potential Benefits of TFLRD • Could achieve early risk reductions on a voluntary basis • Facilities might be motivated to comply with TFLRD if they can meet the requirements by making simple changes • Will “target” emission reductions under the current residual risk program, making them more cost-effective and justifiable • Should provide high quality site-specific emissions data for use in future assessments and emission reduction strategies
Status of TFLRD • EPA management briefed on TFLRD options in September, 2005 • Workgroup is currently developing a draft of the proposed rule • Proposed rule anticipated in early 2006
Generic Approach to Residual Risk The Generic Residual Risk Rule (GRRR)
Background: Current Residual Risk Program • Under the current Residual Risk program EPA will assess approximately 100 source categories • Each source category will be assessed individually • Inefficient approach • Total cost of the program will be between $25 million and $30 million • FY05 budget for Residual Risk is approximately $750K • As resources are reduced, more of the work must be accomplished in house • This will slow the progress of the program • May also result in inappropriate regulation
Background: Goals of a Generic Approach to Residual Risk • Efficient use of resources • By allowing us to focus most of our resources on the highest-risk sources while expending little effort on the low risk sources • We could also distribute the resource burden across EPA, states, and industry • Accurate characterization of risks • GRRR could accomplish this by focusing on risk assessments that use site-specific information
Overview of the Proposed Process for GRRRR • EPA develops single, generic process rule that applies to all sources in all source categories • Step 1: Sources submit information to EPA/ permitting authority • Sources could be required to conduct and submit a risk assessment • For this option we need to develop a review/approval process • Sources could be required to submit facility data (e.g. HAP emission rates, stack parameters) in model-ready format • EPA could then use this data to conduct risk assessments for all sources
Overview of the Proposed Process for GRRR (cont.) • Step 2: Based on the results of their assessments, sources are binned into low, medium, and higher risk categories • Low risk: Maximum cancer risk less than 1 in 1 million and non-cancer target organ specific hazard index < 1 • Medium risk: Above low risk criteria but below cancer risk of 100 in 1 million (non-cancer criteria?) • Higher risk: Above medium risk criteria
Overview of the Proposed Process for GRRR (cont.) • Low risk: Sources meet their 112(f) requirements • No risk reduction requirements under the residual risk program • Medium risk: Some sources must reduce risks further (considering costs/feasibility) • Higher risk: All sources must develop and implement a risk reduction plan that is approved by EPA • Risk reduction plan should bring source at least to the medium risk range
Options for Addressing Sources that Do Not Meet Low Risk Criteria • Option 1: Sources must develop a risk reduction plan that is approved by EPA • This option would likely be reserved for highest risk sources • Option 2: Write a limited number of source category rules • Under this option we could combine multiple source categories into a single rule and allow site-specific compliance based on risk • Option 3: Sources could be required to add new source MACT (or most stringent MACT requirements for source category) • Option 4: Sources could be required to choose control options from a control technology table • Option 5: EPA could delegate oversight of risk reduction to states (in some cases) • States that accept delegation would be responsible for developing a risk reduction plans
Next Steps • We are working with other EPA offices to further develop this concept • Engage stakeholders and obtain input • Form a formal workgroup and begin rule development???
National Air Toxics Assessment (NATA) activities are… • A number of technical support activities designed to provide all parts of EPA's Air Toxics Program with quantitative, policy-relevant, and consistent information: • Emissions inventories • Monitoring network • Air quality, exposure, and risk modeling (called the National Scale Assessment) • Research on effects and assessment tools
What is the National Scale Assessment? • Characterization of air toxics exposure and risk across the nation • Nationwide assessment with census tract resolution for 177 HAPs plus diesel PM • Emissions, modeled ambient concentrations and estimated inhalation exposures from outdoor sources • Cancer and noncancer risk estimates for the 133 HAPs with health data based on chronic exposures
X X X X X X
Goals of the Initial National-Scale Assessment • Identify air toxics of greatest concern • Characterize contributions of different emission sources to exposure and risk • Prioritize collection of new data • Provide a baseline (with ambient data) to track trends and measure progress against goals • Tools for State/Local/Tribal Agencies (and EPA) to prioritize pollutants, emission sources and locations of interest • Provides a starting point for local-scale assessments • Focuses community efforts • Informs monitoring programs • A few pieces of the air toxic puzzle
acetaldehyde acrolein acrylonitrile arsenic compounds benzene beryllium compounds 1,3-butadiene cadmium compounds carbon tetrachloride chloroform chromium compounds coke oven emissions 1,2-dibromoethane (ethylene dibromide) 1,2-dichloropropane (propylene dichloride) 1,3-dichloropropene ethylene dichloride (1,2-dichloroethane) ethylene oxide formaldehyde hexachlorobenzene hydrazine lead compounds manganese compounds mercury compounds methylene chloride (dichloromethane) nickel compounds polychlorinated biphenyls (PCBs) polycyclic organic matter (POM) quinoline 1,1,2,2-tetrachloroethane tetrachloroethylene (perchloroethylene) trichloroethylene vinyl chloride diesel particulate matter Etc. Some of the pollutants included in the National-Scale Assessment
Limitations of the National-Scale Assessment • Inhalation exposure only • Chronic exposures only • 1999 emissions data • Sources of indoor origin generally excluded • 50-km modeling range • Focuses on average/median exposures, not individual extremes • Census tract-level calculations; county-level and higher presentations
Components of the NATANational-Scale Assessment Comparison with Ambient Monitoring Data Emission Inventory Development Emission Processing (EMS-HAP) Air Dispersion Modeling (ASPEN) Inhalation Exposure Modeling (HAPEM) Dose-Response Assessment Risk Characterization
Improvements Over the 1996 National Scale Assessment • Improved quality of inventory • Expanded coverage to include nearly all HAPs • Improved technical quality of modeling analyses • Responded to many of SAB comments • Used latest health risk information • Improved presentation of results • More transparent and accessible website data • Local scale mapping tools