Superfund Risk Assessment: Human Health Topics

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Planning and Scoping

Risk assessments can be more efficiently completed if planning and scoping of the information and data needed to complete the assessment is considered before the field investigations and site characterization work are completed. Although this is sometimes an iterative process (with some collected data revealing the need for more information), planning and scoping before data collection generally reduce both time and cost for the site. Documents and links related to planning and scoping are presented on this webpage.

Planning and Scoping Documents

  1. Role of the Baseline Risk Assessment in Superfund Remedy Selection Decisions, April 22, 1991
    This memo describes the process and purpose of the baseline risk assessment (the latter steps) in terms of remedy selection.
  2. (Revised) Policy on Performance of Risk Assessments During RI/FSs Conducted by PRPs
    As part of the recently announced administrative reforms to the Superfund program, the Administrator stated that EPA would reaffirm its commitment to "allow PRP's to conduct risk assessments under proper circumstances as part of the overall site study (RI/FS)." This memorandum announces EPA's revised policy on allowing PRP's to conduct the risk assessment portion of the RI/FS.
  3. Presenters' Manual for: Superfund Risk and Assessment and How You Can Help
    EPA developed the 40-minute videotape "Superfund Risk Assessment and How You Can Help" to help explain in plain terms the Superfund human health risk assessment process and how communities can be involved.
  4. Risk Assessment Guidance for Superfund, Volume I - Human Health Evaluation Manual
    Part A: Baseline Risk Assessment (1989)
    Supplement to Part A: Community Involvement in Superfund Risk Assessments (1999)
    The purpose of this guidance document is to provide the site team--risk assessor, remedial project manager (RPM), and community involvement coordinator--with information to improve community involvement in the Superfund risk assessment process
    Part B: Development of Risk-based Preliminary Remediation Goals (1991)
    Part C: Risk Evaluation of Remedial Alternatives (1991)
    Part D: Standardized Planning, Reporting and Review of Superfund Risk Assessments (2001)
    Part E: Supplemental Guidance for Dermal Risk Assessment (2004)
    Part F: Supplemental Guidance for Inhalation Risk Assessment (2009)
    EPA Superfund's "Process for Conducting Probabilistic Risk Assessment, RAGS Volume III, Part A" December 2001, EPA 540-R-02-002  Soil Screening Guidance July 1996, December 2002
  5. The Soil Screening Guidance (SSG) presents a framework for developing risk-based, soil screening levels (SSLs) for protection of human health.
  6. Vapor Intrusion Guidance
    EPA's Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA) Technical Guide for Assessing and Mitigating the Vapor Intrusion Pathway from Subsurface Vapor Sources to Indoor Air is intended for use by EPA’s brownfield grantees, or state agencies where vapor intrusion may be of potential concern (for both residential and non-residential settings).
  7. Analytical Methods
    The following EPA Forum on Environmental Measurements link provides information on the collection and analysis of environmental samples.
  8. Data Quality Objectives
    Sampling and analysis activities undertaken during the risk assessment should provide adequate data to evaluate all appropriate exposure pathways. Therefore, risk assessors should be involved in the development of the data quality objectives for sampling and analysis and in selecting the types of sampling and analyses that will be done. The DQOs should address the qualitative and quantitative nature of the sampling data in terms of relative quality and intent for use, to ensure that the data collected will be appropriate for the intended objectives. DQOs are discussed under Section 2.2 of RAGS Part D.
  9. Data Useability in Risk Assessment
    Data quality is an important component of the risk assessment and the evaluation of data quality should be documented. RAGS Part D includes to address this need. In addition, Section 3.1.1 of Risk Assessment Guidance for Superfund (RAGS) Part D discusses standard tables, worksheets, and supporting information. Guidance for Data Useability in Risk Assessment: Quick Reference Fact Sheet (1990)
    Guidance for Data Useability in Risk Assessment (Part A) (1992)
    Guidance for Data Useability in Risk Assessment (Part B) (1992)
  10. Calculating the Concentration Term
  11. Calculating Upper Confidence Limits for Exposure Point Concentrations at Hazardous Waste Sites
  12. Technical Support Center for Monitoring and Site Characterization to provide access to ProUCL Version 5.1
  13. Guidance for Comparing Background and Chemical Concentration in Soil for CERCLA Sites, September 2002
    This document provides guidance to the U.S. Environmental Protection Agency Regions concerning how the Agency intends to exercise its discretion in implementing one aspect of the CERCLA remedy selection process. The guidance is designed to implement national policy on these issues.
  14. Role of Background in the CERCLA Cleanup Program,  April 26, 2002
    This document clarifies the U.S. Environmental Protection Agency (EPA) preferred approach for the consideration of background constituent concentrations of hazardous substances, pollutants, and contaminants in certain steps of the remedy selection process, such as risk assessment and risk management, at Comprehensive Environmental Response, Compensation, and Liability Act (CERCLA or "Superfund") sites.
  15. Land Use in the CERCLA Remedy Selection Process
    OSWER Directive No. 9355.7-04. This directive presents additional information for considering land use in making remedy selection decisions under CERCLA at NPL sites.
  16. Response Actions at Sites with Contamination Inside Buildings (PDF)
    Addresses the use of the CERCLA authority to conduct response actions within buildings that are contaminated. Includes a flow-chart that designates the sequence of steps to take when addressing indoor contamination scenarios. Headquarters consultation requirements are defined. OSWER 9360.3-12, August 1993
  17. Policy on Evaluating Health Risks to Children
    EPA policy to consider the risks to infants and children consistently and explicitly as a part of risk assessments generated during decision making process, including the setting of standards to protect public health and the environment.
  18. Identifying Applicable or Relevant and Appropriate Requirements (ARARs) November 6, 2001
    Memo addressing the use of uranium standards when establishing remediation goals in groundwater in CERCLA (Superfund) sites that may be current or future sources of drinking water.
  19. The following link contains information on addressing asbestos at Superfund sites
  20. Headquarters Consultation for Dioxin Sites OSWER Directive 9200.4-19, December 13, 1996
    This document requests that CERCLA regional offices consult with EPA Headquarters on sites where remediation goals are to be developed for dioxin in soil.
  21. Approach for Addressing Dioxin in Soil and CERCLA and RCRA Sites OSWER Directive 9200.4-26, April 13, 1998
    The purpose of this document is to recommend preliminary remediation goals (PRGs), or starting points for cleaning up dioxin in soil.
  22. EPA FAQ's about the Update to the ATSDR Policy Guideline for Dioxin and Dioxin-Like Compounds in Residential Soil
  23. For lead risk assessment documents, please visit this webpage.
  24. EPA Radiation Risk Assessment Guidance for Superfund sites

Exposure Assessment

Below is a list of relevant human health exposure assessment documents used in Superfund:

  1. Risk Assessment Guidance for Superfund, Volume I - Human Health Evaluation Manual
    Part A: Baseline Risk Assessment (1989)
    Supplement to Part A: Community Involvement in Superfund Risk Assessments (1999)
    The purpose of this guidance document is to provide the site team—risk assessor, remedial project manager (RPM), and community involvement coordinator—with information to improve community involvement in the Superfund risk assessment process
    Part B: Development of Risk-based Preliminary Remediation Goals (1991)
    Part C: Risk Evaluation of Remedial Alternatives (1991)
    Part D: Standardized Planning, Reporting and Review of Superfund Risk Assessments (2001)
    Part E: Supplemental Guidance for Dermal Risk Assessment (2004)
    Part F: Supplemental Guidance for Inhalation Risk Assessment (2009)

    Beginning in 1989, the EPA Superfund Program began releasing its Risk Assessment Guidance for Superfund (RAGS) in three volumes. Volume I addressed human health, and continues to be used. Parts D, E and F were subsequently released to supplement Parts A, B and C of Volume I. RAGS Volume III provides guidance on Probabilistic Risk Assessment, which can be used for both human health and ecological risk assessment, and also continues to be used. RAGS Volume II addressed ecological risk. RAGS Volume II is not provided on this website because it has been replaced by other guidance addressing ecological risk for Superfund Sites.
     
  2. Risk Assessment Guidance for Superfund (RAGS) Volume III - Part A: Process for Conducting Probabilistic Risk Assessment (2001)
     
  3. Land Use in the CERCLA Remedy Selection Process
    OSWER Directive No. 9355.7-04. This directive presents additional information for considering land use in making remedy selection decisions under CERCLA at NPL sites.
     
  4. Standard Default Exposure Factors for Superfund sites
     
  5. U.S. EPA's Center for Public Health and Environmental Assessment's "Guidelines for Exposure Assessment, 1992"
     
  6. U.S. EPA's Center for Public Health and Environmental Assessment's "Exposure Factors Handbook, 2011 Edition"
    1. New Policy on Evaluating Health Risks to Children (October 20, 1995)
       
  7. Summary Report of a Peer Involvement Workshop on the Development of an Exposure Factors Handbook for the Aging, February 2007
     
  8. U.S. EPA's Center for Public Health and Environmental Assessment's Guide to Current Literature on Exposure Factors
    1. Web site summarizing sources of latest information on exposure factors.
    2. U.S. EPA's Center for Public Health and Environmental Assessment's 2008 Child-Specific Exposure Factors Handbook
       
  9. Johnson and Ettinger (1991) Model for Subsurface Vapor Intrusion into Buildings
     
  10. OSWER Draft Guidance for Evaluating the Vapor Intrusion to Indoor Air Pathway
     
  11. The Department of Defense (DoD) 2009 Vapor Intrusion Handbook (PDF) is a tool to assist with evaluating and investigating the vapor intrusion pathway at DoD sites.
    NOTE: The document is stored on DOD's Defense Environmental Network and Information Exhange (DENIX) server. DENIX uses a secure web server using HTTPS (Hypertext Transfer Protocol Secure). After clicking on the link, continue to the server to access the document.
     
  12. The EPA/OSWER Office of Solid Waste (OSW) has developed an approach for conducting multi-pathway, site-specific human health risk assessments on hazardous waste combustion facilities. The technical approach presented in the combustion guidance may be useful when combustion risk is assessed on a Superfund site.
     
  13. Additional Information from EPA's Center for Public Health and Environmental Assessment on Probabilistic Risk Assessment
     
  14. EPA Superfund's "Process for Conducting Probabilistic Risk Assessment", RAGS Volume III, Part A
     
  15. Cumulative Risk Assessment Guidance-Phase I- Planning and Scoping Guidance on Cumulative Risk Assessment, (Part 1)
     
  16. Superfund’s "Soil Screening Guidance", 1996, and 2002
    1. Calculator for site-specific chemical soil screening levels
       
  17. The following link contains information on addressing asbestos at Superfund sites
     
  18. For lead risk assessment documents, please visit this webpage
     
  19. EPA Radiation Risk Assessment Guidance for CERCLA Sites
     
  20. The EPA Office of Pollution Prevention and Toxics has developed software in its Estimation Program Interface ("EPI") which provides physical and chemical properties on contaminants.
     
  21. Determining Groundwater Exposure Point Concentrations 
     
  22. FAQs About Update of Standard Default Exposure Factors 

Acute Hazards

As used here, Acute Threats are defined as: conditions that create the potential for injury or damage to occur to humans or environmental receptors as a result of an instantaneous or short duration exposure to the effects of an accidental release. These conditions may be either chemical or physical in nature and may include toxic, flammable, reactive, explosive, or radioactive hazards.

The EPA evaluates the severity of acutely toxic chemicals by measuring the concentration or dose level that could cause death or serious irreversible health effects after a short exposure. For physical hazards, EPA focuses on other types of effects, such as blast waves from vapor cloud explosions from a flammable substance, as the most serious hazard.

Below is a list of relevant acute hazard documents used in Superfund:

  1. EPA’s Office of Resource Conservation and Recovery's combustion risk Assessment guidance provides a methodology for calculating an acute inhalation hazard quotient (HQ) in Table C-4-1 of the attached guidance.

  2. National Advisory Committee for Acute Exposure Guideline Levels (NAC).
    EPA’s Office of Prevention, Pesticides and Toxic Substances established the NAC in 1995 to develop Acute Exposure Guideline Levels (AEGLs) and supplementary information on hazardous substances for federal, state, and local agencies and organizations in the private sector concerned with emergency planning, prevention, and response. The NAC is a discretionary Federal advisory committee that combines the efforts of stakeholders from the public and private sectors to promote efficiency and utilize sound science.

    Since it began AEGL development with an initial priority list of 85 chemicals in May 1997, the NAC has produced AEGLs for 146 substances (available on EPA's website at https://www.epa.gov/aegl). The AEGLs for a substance take the form of a matrix, with separate levels for mild (AEGL-1), moderate (AEGL-2), and severe (AEGL-3) effects. Each of the effect levels are provided for as many as five different exposure periods, typically 10 and 30 minutes and 1, 4, and 8 hours. Table 2 provides the 1-and 8-hour concentrations for the AEGL-1 and -2, with a superscript that identifies whether the value is final, interim, or proposed.

Below is a list of relevant external links:

  1. The U.S. Agency for Toxic Substances and Disease Registry (ATSDR)
    Develops chronic, intermediate and acute minimal risk levels (MRLs) for some contaminants. An acute MRL is considered an acute Human Health Toxicity value. ATSDR chemical profiles are available on-line.

  2. California Environmental Protection Agency (CalEPA).
    CalEPA has developed acute dose-response assessments for many substances, expressing the results as acute inhalation reference exposure levels (RELs). As with its chronic RELs, CalEPA defines the acute REL as a concentration level at (or below) which no health effects are anticipated. CalEPA's acute RELs are available on-line.

  3. American Industrial Hygiene Association (AIHA).
    AIHA has developed emergency response planning guidelines (ERPGs) for acute exposures at three different levels of severity. The AIHA emergency response planning guidelines are available on-line through the US Department of Energy, represent concentrations for exposure of the general population for up to 1 hour associated with effects expected to be mild or transient (ERPG-1), irreversible or serious (ERPG-2), and potentially life-threatening (ERPG-3). Table 2 provides the ERPG-1 and -2 values.

  4. National Institute for Occupational Safety and Health (NIOSH).
    As part of its mission to study and protect worker health, NIOSH determines concentrations of substances that are immediately dangerous to life or health (IDLHs). IDLHs were originally determined for 387 substances in the mid-1970's as part of the Standards Completion Program (SCP), a joint project by NIOSH and the Occupational Safety and Health Administration (OSHA), for use in assigning respiratory protection equipment. NIOSH is currently evaluating the scientific adequacy of the criteria and procedures used during the SCP for establishing IDLHs. In the interim, the IDLHs have been reviewed and revised. NIOSH maintains an on-line database of IDLHs, including the basis and references for both the current and original IDLH values (as paraphrased from the SCP draft technical standards). Table 2 provides IDLH values divided by 10 to more closely match the mild-effect levels developed by other sources, consistent with methodology used to develop levels of concern under Title III of the Superfund Amendments and Reauthorization Act, and their use in the accidental release prevention requirements under section 112(r) of the Clean Air Act.

  5. U.S. Department of Energy (DOE).
    DOE has defined Temporary Emergency Exposure Limits (TEELs), which are temporary levels of concern (LOCs) derived according to a tiered, formula-like methodology (described at METHODOLOGY FOR DERIVING TEMPORARY EMERGENCY EXPOSURE LIMITS (PDF). DOE describes TEELs as "approximations of potential values" and "subject to change." The EPA’s emergency planning program (section 112(r)) does not generally rely on them, and they are provided in Table 2 purely to inform situations in which no other acute values are available. For example, a finding of an acute exposure near a TEEL may indicate the need for a more in-depth investigation into the health effects literature. TEELs are not recommended as the basis of regulatory decision-making. Like ERPGs, TEELs are multiple-tiered, representing concentrations associated with no effects (TEEL-0), mild, transient effects (TEEL-1), irreversible or serious effects (TEEL-2), and potentially life-threatening (TEEL-3). Consistent with DOE's intent, Table 2 provides the TEEL-0 and -1 concentrations for substances that lack acute values from other sources.

  6. National Library of Medicine (NLM) Hazardous Substances Data Bank
    Broad scope in human and animal toxicity, safety and handling, environmental fate, and more. Scientifically peer-reviewed. The NLM Hazardous Substances Data Bank is available on-line.

Toxicity (Hazard Identification and Dose Response)

Related Links

Dose-Response Assessment is the process of quantitatively evaluating the toxicity of a given chemical agent as a function of human exposure to that chemical agent. The relationship between the dose of the contaminant administered or received and the incidence of adverse health effects in the exposed population forms the basis for the quantitative dose-response relationship. From these relationships, toxicity values (e.g., reference doses and slope factors) are derived that can be used to estimate the incidence or potential for adverse effects in an exposed population.

Hazard Identification is the process of determining whether exposure to a chemical agent can cause an increase in the incidence of a particular adverse health effect (e.g., cancer, birth defects) and whether the adverse health effect is likely to occur in humans. The process examines the available scientific data for a given chemical (or group of chemicals) and develops a weight of evidence to characterize the link between the negative effects and the chemical agent.

Below is a list of relevant toxicity documents used in Superfund:

  1. Memorandum: Human Health Toxicity Values in Superfund Risk Assessments (Human Health Toxicity Value Hierarchy)(PDF)
  2. Use of IRIS Values in Superfund Risk Assessment OSWER Directive 9285.7-16, December 21, 1993 (PDF)
    This memorandum clarifies the policy stated at section 7.4.1 of the December 1988 Risk Assessment Guidance for Superfund (Volume I) Human Health Evaluation Manual (Part A) (RAGS) on the use of Integrated Risk Information System (IRIS) values in performing health risk assessments.
     
  3. Recommendations on the Use of Chronic or Subchronic Noncancer Values for Superfund Human Health Risk Assessments, May 26, 2021 (PDF) 
    This memo provides recommendations from the Office of Land and Emergency Management (OLEM) regarding the use of the subchronic toxicity value rather than the chronic value for 19 specific chemicals.
     
  4. Reference Dose (RfD): Description and Use in Health Risk Assessments 1993
    This concept paper describes the U.S. Environmental Protection Agency's (U.S. EPA) principal approach to and rationale for assessing risk for health effects other than cancer and gene mutations from chronic chemical exposure.
     
  5. Cancer Guidelines
    EPA's Guidelines for Carcinogen Risk Assessment are intended to aid scientists in assessing the possible cancer risks caused by exposure to pollutants in the environment. Released in March 2005, the revised Cancer Guidelines integrate recent advances in scientists' understanding of the processes involved in the development of cancer.
     
  6. Benchmark Dose Technical Support Document External Review Draft, EPA/630/R-00/001, October 2000. Risk Assessment Forum, Washington, DC
    The purpose of this document is to provide guidance for the Agency and the outside community on the application of the benchmark dose approach to determining the point of departure (POD) for linear or nonlinear extrapolation of health effects data.
     
  7. Methods for Derivation of Inhalation Reference Concentrations and Application of Inhalation Dosimetry 1994, EPA/600/8-90/066F
    This document describes the U.S. Environmental Protection Agency (EPA) methodology for estimation of inhalation reference concentrations (RfCs) (earlier terminology was "inhalation reference dose" or "RfDi") as benchmark estimates of the quantitative dose-response assessment of chronic noncancer toxicity for individual inhaled chemicals.
     
  8. Interim Policy for Particle Size and Limit Concentration Issues in Inhalation Toxicity: Notice of Availability (1994)
    EPA has made available to all interested parties, an Interim Policy for Particle Size and Limit Concentration Issues in Inhalation Toxicity Studies which deals with several of the most controversial issues encountered in inhalation toxicity studies.
     
  9. Guidelines for the Health Risk Assessment of Chemical Mixtures (PDF) 1986, Federal Register 51(185):34014-34025.
    The guidelines are intended to guide Agency analysis of information relating to health effects data on chemical mixtures in line with the policies and procedures established in the statues administered by the EPA.
     
  10. Supplementary Guidance for Conducting Health Risk Assessment of Chemical Mixtures (PDF), EPA630-R-00-002 (August, 2001)
    This document is a supplement to the EPA Guidelines for the Health Risk Assessment of Chemical Mixtures of 1986. The 1986 Guidelines represent the Agency's science policy and are a procedural guide for evaluating data on the health risks from exposures to chemical mixtures.
     
  11. Guidelines for Mutagenicity Risk Assessment
    The Guidelines for Mutagenicity Risk Assessment (hereafter Guidelines) are intended to guide Agency analysis of mutagenicity data in line with the policies and procedures established in the statutes administered by EPA.
     
  12. Guidelines for Neurotoxicity Risk Assessment
    These Guidelines are intended to guide Agency evaluation of agents that are suspected to cause neurotoxicity, in line with the policies and procedures established in the statutes administered by the Agency.
     
  13. Guidelines for Reproductive Toxicity Risk Assessment
    This notice describes the scientific basis for concern about exposure to agents that cause reproductive toxicity, outlines the general process for assessing potential risk to humans from exposure to environmental agents, and addresses Science Advisory Board and public comments on the 1994 Proposed Guidelines for Reproductive Toxicity Risk Assessment.
     
  14. Distributed Structure-Searchable Toxicity (DSSTox) Database Network is a project of EPA's Computational Toxicology Program, helping to build a public data foundation for improved structure-activity and predictive toxicology capabilities. The DSSTox website provides a public forum for publishing downloadable, structure-searchable, standardized chemical structure files associated with toxicity data.
     
  15. OncoLogicT is a desktop computer program that evaluates the likelihood that a chemical may cause cancer. OncoLogicT has been peer reviewed, runs on a Windows® PC, and is being released by EPA at no cost, to make it available to any researcher or organization wishing to evaluate cancer potential of chemicals. The OncoLogicT installer is posted at the bottom of this page.
     
  16. Headquarters Consultation for Dioxin Sites (PDF) OSWER Directive 9200.4-19, December 13, 1996
    This document requests that CERCLA regional offices consult with EPA Headquarters on sites where remediation goals are to be developed for dioxin in soil.
     
  17. Approach for Addressing Dioxin in Soil and CERCLA and RCRA Sites (PDF) OSWER Directive 9200.4-26, April 13, 1998
    The purpose of this document is to recommend preliminary remediation goals (PRGs), or starting points for cleaning up dioxin in soil.
     
  18. EPA FAQ's about the Update to the ATSDR Policy Guideline for Dioxin and Dioxin-Like Compounds in Residential Soil
     
  19. For lead risk assessment documents, please visit this webpage
     
  20. Bioavailability is the amount of a contaminant that is absorbed into the body following skin contact, ingestion, or inhalation. Relative bioavailability is how much of a contaminant is absorbed by humans from soil as compared to how much of that contaminant is absorbed from food or water. This Web site describes how EPA is incorporating relative bioavailability information for human exposures at Superfund sites exposed to soil contaminants via the oral pathway.
     
  21. Hazard Assessment (HA) for Munitions and Explosives of Concern (MEC)
     
  22. Revised Assessment Guidance for Perchlorate (PDF)
     
  23. Provisional Guidance for Quantitative Risk Assessment of Polycyclic Aromatic Hydrocarbons, US EPA, 1993,  EPA/600/R-93/089 (July, 1993) (PDF)
     
  24. EPA Radiation Risk Assessment Guidance for Superfund sites
     
  25. Interim TCE Value withdrawal memo, January 15,2009 (PDF)
    The Office of Solid Waste and Emergency Response has withdrawn the January 15, 2009, guidance entitled "Interim Recommended Trichloroethylene (TCE) Toxicity Values to Assess Human Health Risk and Recommendations for the Vapor Intrusion Pathway Analysis."

Below is a list of relevant external links:

  1. Risk assessors completing risk assessments on Superfund sites may find the following Environmental Council of States (ECOS) paper: Identification and Selection of Toxicity Values/Criteria for CERCLA and Hazardous Waste Site Risk Assessments in the Absence of IRIS Values (DOC), useful in evaluating and selecting human health toxicity values for use in risk assessments. Both EPA/OSWER and EPA/ORD scientists and risk assessors, as well as Department of Defense and California Environmental Protection Agency scientists and risk assessors, participated in the writing of this paper. These parties find the paper and its seven preferences on evaluating toxicity values useful.
  2. The California Environmental Protection Agency (Cal EPA)/Office of Environmental Health Hazard Assessment Toxicity Criteria Database
    The California Environmental Protection Agency (Cal EPA)/Office of Environmental Health Hazard Assessment derives human health toxicity values, which the EPA Superfund Program sometimes uses, such as when EPA has not derived a needed toxicity value. Cal EPA toxicity assessments and values can be obtained from this Cal EPA database.
  3. The World Health Organization/International Programme
    The World Health Organization/International Programme on Chemical Safety's (IPCS) Concise International Chemical Assessment Documents may also be considered a Tier 3 source, when no Tier 1 (IRIS) or Tier 2 (Provisional Peer Reviewed Toxicity Values) values are available. Chemical safety is achieved by dealing with chemicals appropriately to ensure the safety of people and the environment. The term ‘chemical safety’ encompasses all chemicals – natural and manufactured – and the full range of exposure situations from the natural presence of chemicals in the environment to their extraction or synthesis, industrial production, transport, use and disposal. Key chemicals of concern today include asbestos, pesticides, lead, mercury, and dioxins.
  4. The 2005 World Health Organization Re-evaluation of Human and Mammalian Toxic Equivalency Factors for Dioxins and Dioxin-like Compounds
    In 1998 and again in 2005 the World Health Organization/International Programme on Chemical Safety (WHO/IPCS) evaluted the relative cancer potency of chlorinated dioxins, chlorinated dibenzofurans and some polychlorinated biphenyls (PCBs) and derived toxicity equivalency factors (TEFs) which can be used in conjunction with cancer toxicity values from other sources to evaluate the cancer risk of these contaminants. The EPA Superfund Program supports the use of the current (2005) TEFs from the WHO/IPCS, which are presented in this document.

Risk Characterization

In Risk Characterization, the information from Hazard Identification, Exposure Assessment, Dose-Response Assessment are summarized and integrated into quantitative and qualitative expressions of risk. To estimate potential noncarcinogenic effects, comparisons are made between projected intakes of substances and toxicity values; to estimate potential carcinogenic effects, probabilities that an individual will develop cancer over a lifetime of exposure are determined from projected intakes and chemical-specific dose-response information. Major assumptions, scientific judgments, and to the extent possible, estimates of the uncertainties embodied in the assessment are also presented.

Risk Characterization Documents

Below is a list of relevant risk characterization related documents used in Superfund:

Related Links
  1. Part A: Baseline Risk Assessment (1989)
     
    1. Supplement to Part A: Community Involvement in Superfund Risk Assessments (1999)
      The purpose of this guidance document is to provide the site team—risk assessor, remedial project manager (RPM), and community involvement coordinator—with information to improve community involvement in the Superfund risk assessment process.
  2. Part B: Development of Risk-based Preliminary Remediation Goals (1991)
  3. Part C: Risk Evaluation of Remedial Alternatives (1991)
  4. Part D: Standardized Planning, Reporting and Review of Superfund Risk Assessments (2001)
  5. Part E: Supplemental Guidance for Dermal Risk Assessment (2004)
  6. Part F: Supplemental Guidance for Inhalation Risk Assessment (2009)
  7. The EPA/OSWER Office of Solid Waste (OSW) has developed an approach for conducting multi-pathway, site-specific human health risk assessments on hazardous waste combustion facilities. The technical approach presented in the combustion guidance may be useful when combustion risk is assessed on a Superfund site.
  8. EPA Guiding Principles on Monte Carlo Analysis
  9. Risk Assessment Guidance for Superfund, Volume III, Probabilistic
  10. Addressing Asbestos at Superfund Sites
  11. Headquarters Consultation for Dioxin Sites OSWER Directive, 9200.4-19, December 13, 1996
    This document requests that CERCLA regional offices consult with EPA Headquarters on sites where remediation goals are to be developed for dioxin in soil.
  12. Approach for Addressing Dioxin in Soil and CERCLA and RCRA Sites (PDF) OSWER Directive 9200.4-26, April 13, 1998
    The purpose of this document is to recommend preliminary remediation goals (PRGs), or starting points for cleaning up dioxin in soil.
  13. EPA FAQ's about the Update to the ATSDR Policy Guideline for Dioxin and Dioxin-Like Compounds in Residential Soil
  14. Lead Risk Assessment documents.
  15. EPA Radiation Risk Assessment Guidance for CERCLA Sites
Below is a relevant external link:

Spatial Analysis and Decision Assistance
Spatial Analysis and Decision Assistance is a freeware program developed at the University of Tennessee with funding from EPA, NRC, and DOE that provides comprehensive risk assessment tools in a spatial modeling environment. Risk assessors can use SADA to perform traditional risk assessment PRG calculations, PRG screens, and forward human health calculations for one or more contaminants.

Users have complete control over all toxicological data, physical properties, and landuse/pathway exposure parameters to create site specific risk assessments. In addition, the risk models are integrated with SADA's spatial analysis tools, decision frameworks,and sample design strategies allowing users drive a risk based characterization from a preliminary initial sample design through a final feasibility study. In addition, SADA allows users to import their own site or region specific screening or decision threshold values separately from SADA's own risk modeling tools.

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Last updated on November 25, 2024