Health-based Provisional Advisory Levels (PALs) for homeland security

Abstract

The Homeland Security Presidential Directive #8 (HSPD-8) for National Emergency Preparedness was issued to " establish policies to strengthen the preparedness of the United States to prevent and respond to threatened or actual domestic terrorist attacks, major disasters, and other emergencies by requiring a national domestic all- hazards preparedness goal. "In response to HSPD-8 and HSPD-22 (classified) on Domestic Chemical Defense, the US Environmental Protection Agency (US EPA) National Homeland Security Research Center (NHSRC) is developing health-based Provisional Advisory Levels (PALs) for priority chemicals (including chemical warfare agents, pesticides, and toxic industrial chemicals) in air and drinking water. PALs are temporary values that will neither be promulgated, nor be formally issued as regulatory guidance. They are intended to be used at the discretion of risk managers in emergency situations. The PAL Program provides advisory exposure levels for chemical agents to assist in emergency planning and response decision-making, and to aid in making informed risk management decisions for evacuation, temporary re-entry into affected areas, and resumed-use of infrastructure, such as water resources. These risk management decisions may be made at the federal, state, and local levels. Three exposure levels (PAL 1, PAL 2, and PAL 3), distinguished by severity of toxic effects, are developed for 24-hour, 30-day, 90-day, and 2-year durations for potential exposure to drinking water and ambient air by the general public. Developed PALs are evaluated both by a US EPA working group, and an external multidisciplinary panel to ensure scientific credibility and wide acceptance. In this Special Issue publication, we present background information on the PAL program, the methodology used in deriving PALs, and the technical support documents for the derivation of PALs for acrylonitrile, hydrogen sulfide, and phosgene.

Developing Health-Based Pre-Planning Clearance Goals for Airport Remediation Following a Chemical Terrorist Attack: Decision Criteria for Multipathway Exposure Routes

“…These levels (Provisional Advisory Levels; PALs) are being derived for assumed continuous 24-h, 30-d, 90-d, and 2-yr exposure durations for both inhalation and oral exposure routes and 3 tiers of effect, with tier 1 being least severe and tier 3 being most severe. As provisional values, PALs are considered “temporary values that will neither be promulgated, nor be formally issued as regulatory guidance” (Adeshina et al 2009). Rather their intent is to “assist in emergency planning and decision-making,” and for use at the discretion of risk managers.…”

Extrapolating the Acute Behavioral Effects of Toluene from 1- to 24-h Exposures in Rats: Roles of Dose Metric and Metabolic and Behavioral Tolerance

“…Studies of this nature indicate that concentration exerts a stronger effect on acute toxicity than does time; therefore, the rule is often modified by raising C to some power, as proposed by ten Berge et al (1986), with the value of the exponent (n) derived empirically from existing concentrationduration relationships. Guidelines that use this rule, C n 3 t, include Acute Exposure Guideline Levels for one-time exposures of short durations (10 min-8 h) (http://www.epa.gov/ opptintr/aegl/; NRC, 2001) and Provisional Advisory Levels for one-time chemical exposures of durations of 24 h, 30 days, or 2 years (Adeshina et al, 2009).…”