The increased risk of a terrorist attack in the U.S. involving chemical agents has created new challenges for many departments and agencies across the federal government. Within the Department of Health and Human Services (DHHS), the NIH is leading the development of new and improved medical countermeasures designed to prevent, diagnose, and treat the conditions caused by potential agents of terrorism. Historically, biomedical research aimed at countering the effects of chemical warfare agent exposure has been supported primarily through the Department of Defense (DoD), which has focused on developing medical countermeasures to be used in the context of traditional warfare. The NIH Chemical Threats program is part of the larger biodefense program coordinated by the NIAID that includes Biological and Radiation/Nuclear threats. The NIAID and the NINDS, working with the DoD, held a series of workshops to identify research gaps in our knowledge of medical countermeasures effective against chemical threat agents.