Investigation of Texas poison center calls regarding a chlorine gas release: implications for terrorist attack toxicosurveillance.

The investigation reported here was conducted to describe the pattern of calls received by the Texas Poison Center Network (TPCN) in relation to a chlorine gas release that resulted from a train collision in Bexar County, Texas, on June 28, 2004, and to test various methods for conducting toxicosurveillance. TPCN received a total of 42 calls; the first call was received approximately 35 minutes after the collision. Calls continued for 10 days after the collision. Comparison of the number of calls received from Bexar County on the collision date with the number of similar calls received in the past revealed that numbers for this collision date were elevated for total calls, total information calls, total human exposure calls, chlorine gas calls, and calls involving coughing or choking, headache, throat irritation, or bronchospasm. When a similar analysis was performed for the entire state, call numbers were elevated only for chlorine gas calls and calls involving bronchospasm.