&EPA www.epa.gov/nhsrc 4 technical BR IEP Provisional Advisory Levels (PALs) for Hazardous Agents PALs are advisory risk values intended to aid decision making during an emergency event. Few health-based guidelines are available to inform decisions regarding the evacuation from or reoccupation of buildings or sites, or the cessation and subsequent re-use of water resources, following their contamination through the accidental or intentional release of toxic chemicals or chemical warfare agents, or following a large-scale disaster. To address this need, EPA/ORD's National Homeland Security Research Center (NHSRC) develops health-based Provisional Advisory Levels (PALs) for high priority chemicals including toxic industrial chemicals and chemical warfare agents, for both inhalation and oral exposures. Oral PALs are targeted to drinking water ingestion, but are applicable to other oral exposures such as soil ingestion. PALs are advisory levels for exposure to hazardous chemicals for defined durations of exposure: • 24 Hours, • 30 Days, • 90 Days, and • Two years. PALs Development PAL1 values are developed for mild, transient, reversible effects; PAL 2 values address serious, irreversible and/or escape-impairing effects; and PAL 3 values address lethality, morbidity or life-threatening effects. PAL values are developed by typical noncancer risk assessment methods by (a) identifying priority chemicals; (b) understanding their environmental fate and persistence; (c) researching and summarizing their toxic effects, modes of toxic action, and organ distribution in humans and test animals; (d) identifying key studies, sorting their reported effects into PAL tiers and identifying the doses producing those effects; (e) adjusting the doses to account for information gaps (uncertainty), and (f) presenting risk values as concentrations of the chemical in air and water by accounting for body mass and the amount of water ingested per day. PAL-Based Decision Examples PAL 3 PAL 2 PAL 1 ! Lethality, Morbidity, I Life-threatening | effects Irreversible or t Escape-impairing | effects | Reversible changes in I biomarkers or | baseline physiology Adverse health effects are not expected Increasing chance of fatalities t/\ ------------------—~ Increasing chance of serious, irreversible effects Increasing chance of discomfort, irritation /\ Q) L. 3 V) O a x LU U.S. Environmental Protection Agency Office of Research and Development, Homeland Security Research Program EPA 600/S-17/044 February, 2017 ------- PALs have been determined for several chemicals, including: Acrolein Acrylonitrile Aldicarb Ammonia Arsine Boron trifluoride Carbon disulfide Carbonyl difluoride Chlorfenvinphos Chlorine Chloropicrin Chlorpyrifos Cyanide Diborane Dimethyl phosphite Fentanyl Flouroacetate salts G Nerve Agents Hydrazine Hydrogen bromide Hydrogen chloride Hydrogen selenide Hydrogen sulfide Methylphosphonic acid Lewisite Malathion Methomyl Methyl isocyanate Methyl parathion Mevinphos Oxamyl Phencyclidine Phosgene Sulfur mustard Titanium tetrachloride Trimethyl phosphite PALs STEERING COMMITTEE ORD/NHSRC has established a PALs Steering Committee comprising scientists and managers from ORD, program offices and the regions. The committee meets approximately quarterly to discuss issues related to user needs, emerging contaminants, risk methods and communication. AVAILABILITY OF PALs Intended users of PAL values include EPA emergency planners and responders, risk assessors, and on-scene coordinators. For more information, please follow the "Assessing Exposure" link under the "Characterizing Contamination and Assessing Exposure" section of our webpage: http://www2.epa.gov/homeland-securitv-research Technical Contact: John Lipscomb EPA/ORD/NHSRC lipscomb.iohn@epa.gov 513-569-7217 General Feedback/Questions: Kathy Nickel (nickel.kathv@epa.gov) U.S. EPA's Homeland Security Research Program (HSRP) develops products based on scientific research and technology evaluations. Our products and expertise are widely used in preventing, preparing for, and recovering from public health and environmental emergencies that arise from terrorist attacks or natural disasters. Our research and products address biological, radiological, or chemical contaminants that could affect indoor areas, outdoor areas, or water infrastructure. HSRP provides these products, technical assistance, and expertise to support EPA's roles and responsibilities under the National Response Framework, statutory requirements, and Homeland Security Presidential Directives. U.S. Environmental Protection Agency Office of Research and Development, Homeland Security Research Program EPA/600/S-17/044 February 2017 ------- |