Organophosphate exposures in the United States: a longitudinal analysis of incidents reported to poison centers.

The implementation of the Food Quality Protection Act of 1996 resulted in a decision by the U.S. Environmental Protection Agency to phase out and eliminate the use of organophosphate insecticides in residential environments. The phase-out and cancellation process began in the year 2000 and was complete in 2005. The purpose of this investigation was to utilize national Poison Control Center data to assess whether the risk mitigation decision had an impact on the number of incident cases involving organophosphates in the United States. Organophosphate exposure incident data were extracted from Annual Reports of the American Association of Poison Control Centers Toxic Exposure Surveillance System (TESS) for the years 1995 to 2004. The number of organophosphate exposure incidents peaked at 20,135 in 1997, and declined in each subsequent year. A statistically significant decrease was observed in the average annual number of organophosphate exposure incidents when comparing data from the time periods before (1995-1999) and after (2000-2004) the commencement of the phase-out process. The decrease in organophosphate incident cases was observed for all age categories, as well as for the circumstances surrounding the exposure (unintentional and intentional exposure incidents). TESS data showed a significant decrease in incident cases involving organophosphates in association with the phase-out from residential uses. The results of this investigation are consistent with other studies that have reported that regulatory restriction of access to pesticide formulations may have a significant impact on the number of human exposure incidents.