Chemical Warfare Agent Criteria

  Since 1992, staff in two Life Sciences Division sections have been developing estimates of chronic human toxicity, known as Reference Doses, for several nerve and vesicant chemical warfare agents. This work has been supported by the U.S. Army Environmental Center and the U.S. Army Center for Health Promotion and Preventive Medicine, located at the Aberdeen Proving Ground, Maryland.

  A Reference Dose (RfD) is a USEPA concept defined as "a daily exposure level for the human population, including sensitive subpopulations, that is likely to be without an appreciable risk of deleterious effects during a lifetime." Expressed in units of mg/kg/da, RfDs are considered estimates of "acceptable" exposure for use in evaluating potential noncarcinogenic effects associated with industrial compounds, particularly those found at Superfund sites.

  However, until the Life Sciences Team began their work, there were no RfDs for chemical warfare agents. As a consequence, the Army has faced a regulatory dilemma caused by the absence of a firm chronic toxicological basis on which to develop cleanup standards. In the absence of approved RfDs, civilian regulatory authorities responsible for cleanup action have been considering "no-detect" as the amount of residual agent contamination to be permitted. Achieving such values has no toxicological basis, requires many resources, is time consuming, and creates delays in mitigation. The RfD values developed by the Life Sciences Team provide an appropriate alternative in a format that is familiar to, and commonly used by, civilian regulators responsible for site cleanup after release of industrial compounds.

  Documentation prepared by the team has been reviewed and approved through the Strategic Environmental Research Development program, the Office of the Army Surgeon General, and the National Center for Environmental Health. As such, the U.S. Army Office of the Surgeon General considers the ORNL-developed values to be "Interim Army Chronic Toxicological Criteria" to be used Army-wide for application to the management of items or media contaminated with chemical warfare agents. These values will be considered "interim" pending review by the National Research Council Committee on Toxicology.

Contact: Annetta Watson
Telephone: 423-576-2124
E-Mail: apw@ornl.gov