OVERVIEW OF RESIDUAL RISK PERF 2004 Fall Meeting

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OVERVIEW OF RESIDUAL RISKPERF 2004 Fall Meeting

• R. W. Biles
• October 19, 2004
• Bob Biles - ExxonMobil Biomedical Sciences, Inc.

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Objectives

• Provide overview of EPA Residual Risk Program and
  regulatory process
• Provide some Agency thought processes to address
  Residual Risk
• Provide example of Refinery Residual Risk Rule
• Stimulate coordination/interaction between
  company technical and regulatory skills
• (Acknowledgement EPA, API, various sources)

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Residual Risk Mandate from Congress

• Assess risks from specific stationary sources
• that emit air toxics, after technology-based
• (MACT) standards are in place (112f)
• Set additional standards if those MACT standards
  do not protect the public health with an ample
  margin of safety AMOS
• Set additional standards if necessary to prevent
  adverse environmental effects
• Maximum Achievable Control Technology- MACT

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The Residual Risk Program - Facts

• RR Rule within 8 years of MACT promulgation
• Report to Congress (released 3/99) describes
• Risk assessment methods for use across the Air
  Toxics Program
• Approach for conducting residual risk analyses
• Cost / energy / safety / other relevant factors
  can be considered

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Residual Risk Considerations

• Public health significance after MACT
• Methods / costs to reduce residual risks
• State of knowledge-HAP health risk
• Risks of Background concentration(s)
• Uncertainty / variability in risk estimation

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Residual Risk Risk Assessment Approach

• Agency- 1) Internal Assessment, 2) Rule
• Consistent with Agency human health and eco risk
  assessment technical guidance and policies
• Will use a tiered approach
• Screening level assessment
• Refined assessment
• Depending on characteristics of HAP's, assessment
  will address
• Single or multiple pathways
• Human and ecological endpoints
• QUESTION Use all HAPs (188) or driver HAPs

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Residual Risk Risk Management

• For carcinogens
• Linear dose response model unless data support
  threshold mechanism
• Assume additivity for all carcinogens, or where
  data permit, consider chemical interactions
  (e.g., synergism / antagonism)
• For non-cancer effects
• Use EPA reference concentration (RfC / RfD) or
  comparable criteria from other government
  agencies
• Consider additivity for HAP's with similar health
  effects
• Base decisions on modeled air concentrations, or
  for refined assessments, estimate size and
  characteristics of exposed population

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Risk Management Framework

• 1989 Benzene NESHAP 2-step policy applying
  AMOS
• MIR of 10-4 upper range of acceptability, but
  not rigid line
• EPA strives to provide protection to the greatest
  number possible to a MIR level no higher than
  10-6
• Consider all health information, uncertainty, and
  "effects due to co-location of facilities
• Consider cost, technical feasibility

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Overview of Benzene NESHAP Relevant Risk Ranges
Ample Margin of Safety with consideration of
costs, technical feasibility and other factors
Risk Unsafe Action needed to reduce risks

• Ample Margin
• of
• Safety

10-6
10-4
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Evolving Program Structure

• An entire facility can meet requirements of
  section 112(f)
• A source in the category can meet the
  requirements section 112(f) via a step-wise
  approach

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Residual Risk Process for a Source Category
Collect information on source characterization
and risk reduction options

• Residual Risk Test
• (done by EPA)

Show at least one facility gt10-6, or HIgt1.0
Evaluation of Risk Reduction Options
No
Rule
Tiered Risk Assessment to determine if residual
risk requirements are met (done by source)
Risk gt what the rule allows select risk
reduction option from menu based on criteria
specified in the rule
Risk lt what the rule allows no need for
additional reductions
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Risk Test

• Purpose to determine if the development of a
• standard is required. A standard is required
  if
• One source in the category is identified as
  exceeding a lifetime excess cancer risk to the
  individual most exposed of one in one million, or
  if any target-organ-specific Hazard Index exceeds
  1.0
• Designed to be a simple exercise, not resource
  intensive

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Residual Risk Test (continued)

• If no source in the category exceeds these
  criteria (including consideration of multimedia
  exposures and ecological effects)
• Document the outcome
• Effort for that category (or subcategory) is
  complete
• In other words, do not proceed to risk reduction
  evaluation or to rule development
• Otherwise, proceed to data collection, analysis
  and rule development

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Residual Risk Rule

• EPA writes a residual risk rule for the source
  category (amendment to NESHAP)
• Considers economic, social, political factors in
  addition to risk
• Affects all sources within the category
• Includes applicability criteria
• Only sources matching these criteria must reduce
  emissions and risks
• Rule may specify
• Control equipment
• Performance (e.g., ambient concentrations,
  emission rates, percent reduction)
• Work practices
• Pollution prevention
• Other

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Risk Target

• Tiered approach for determining whether a source
  in the category needs to reduce risks or not
• Tiers may include
• Look-up chart or table included in the rule
• Chart developed by EPA for a specific source
  category
• More traditional risk assessment approach
• Modeling using guidance and software provided by
  EPA

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Total Facility Low Risk Demonstration (TFLRD)

• Voluntary option available to facilities with at
  least one MACT source
• Source conducts total facility risk assessment
• Sources submit risk assessment to permitting
  authority
• Sources certify accuracy of assessment
• 3rd party review? State review? EPA review?
  Audit?
• Parameters included in low risk demonstration
  incorporated into Title V permit
• Parameters become enforceable permit limits
• Facilities that demonstrate their low risk status
  (e.g. maximum cancer risk lt 1E-06 and noncancer
  HI lt 1.0) automatically satisfy the 112f
  requirements for all their MACT sources

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EXAMPLE-EPAs Risk Test Findings- Refinery

• EPAs Risk Test suggests
• A few sources at or slightly above 1 x 10-4
• Majority fall between 1 x 10-4 and 1 x 10-6
• A few sources at or below 1 x 10-6
• Industry believes this analysis overstates the
  actual risks

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EPAs Risk Test Findings-Refinery (continued)

• However, the AB-2588 database and the Risk Test
  both show that
• Majority of risk comes from RMACT 1 sources
• Benzene is the risk driver HAP
• Inhalation pathway dominates
• Noncancer HAPs are not major risk drivers

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Areas of Concern with Risk Test - Refinery

• Idealized refineries vary greatly from actual
  plant configuration
• A number of plants are not located correctly
• The Risk Test inventories are biased high based
  on Louisiana permit info
• The Risk Test therefore provides insufficient
  foundation to make decisions about
• the need for additional risk reduction
• the actual effectiveness of risk reduction
  alternatives
• Communication to the public needs to reflect
  these uncertainties in the risk results

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Benzene Emissions1999 Refinery TRI vs. EPA
Refinery Emissions Model
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Results Overstate Risk from California Facilities

• Under current AB2588 risk assessments no
  California refinery exceeds 10-5
• EPA results for same facilities show higher risk,
  including 1 facility at 10-4

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Distribution of Facilities in Various Risk Ranges
of Facilities
Risk Ranges x in a Million
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Our Common Problem

• Any requirements for additional controls can not
  reasonably be based on the results of the Risk
  Test
• Instead any requirements for controls should be
  based on improved data and analysis
• How can we work together so that EPA has the
  information it needs to make and defend the
  residual risk regulatory decisions for
  refineries?

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Residual Risk - Future

• Complete current standards with court-ordered
  deadlines
• Coke ovens final 2005
• Dry cleaning final 2006
• HON final 2006
• Halogenated Solvents final 2006
• Refinery- final 2007 (not court ordered)
• Complete 4 proposals of no further controls by
  end of 2006
• Industrial cooling towers
• Magnetic tape
• Ethylene oxide sterilizers
• Gasoline distribution

dates under negotiation
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Challenges Facing Residual Risk Program

• Develop rules which target high-risk facilities
  in categories without impacting low-risk ones
• Process should be simple, efficient
• Process should be implementable by States
• Develop innovative ways to reduce risks where
  controls are not available
• MACT may have been effective, yet risks may still
  be high?
• Health Benchmarks- IRIS?

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Back-up
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EPA Refinery Residual Risk AssessmentRefinery
Layout
Emissions basis derived from 9 Louisiana
refineries