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.

Keywords::

• PAL
• Emergency Planning
• inhalation
• drinking water

Acknowledgments

The authors are grateful for the scientific rigor provided by Oak Ridge National Laboratory and the Expert Consultation Panel in development of the PAL process and technical documents. Scientists from several US EPA program offices and research centers have also contributed to the development and review PAL documents. In addition, the authors are grateful for the assistance of Debra Stewart in preparation of the manuscript. The views expressed in this paper are those of the authors and do not necessarily reflect the views or policies of the US Environmental Protection Agency.

Declaration of interest: This work was prepared under two Interagency Agreements (IAGs): IAG No. 1824-S870-T1 with the U.S. Department of Energy and IAG No. DW-89-92241401 with the U.S. Environmental Protection Agency. The Oak Ridge National Laboratory is managed and operated by UT-Battelle, LLC for the U.S. Department of Energy under contract DE-AC05-00OR22725.