The Hazardous Materials Exposure Information Service (HMEIS) was established at the Washington Poison Center (WPC) to rapidly provide information to medical professionals who treat victims of hazardous-materials exposure. Incident description and exposure information is collected from on-site hazardous-materials teams and immediately analyzed by WPC medical toxicologists. Diagnostic and treatment recommendations are provided to prehospital personnel and receiving physicians. Over the first 22 months of operation, 50 calls were received that met HMEIS criteria. Of the 466 individuals exposed, 256 (55%) were transported to a medical facility for treatment. When the WPC was contacted before the decision to transport a patient to a medical facility, 28 of 185 exposure victims (15%) were transported, compared with a transport rate of 81% of exposure victims (66% change; 95% confidence interval [CI], 60% to 72%) in all other concurrent incidents and a historical transport rate of 63% (25% change; 95% CI, 14% to 36%) before the establishment of the HMEIS. These findings, although preliminary and subject to potential confounding, suggest that the HMEIS reduces health care costs through more efficient use of medical resources. [Burgess JL, Keifer MC, Barnhart S, Richardson M, Robertson WO: Hazardous Materials Exposure Information Service: Development, analysis, and medical implications. Ann Emerg Med February 1997;29:248-254.]