Community exposure following a drip-application of chloropicrin

To evaluate illnesses resulting from community exposure to chloropicrin on October 5, 2005, in the agricultural community of Salinas, California.

A cross-sectional interview survey was conducted of 142 households downwind from the application site in neighborhoods that were sources of emergency calls. A total of 439 residents of the 142 households in affected neighborhoods and 1 emergency responder were interviewed. The authors assessed exposure to chloropicrin resulting from the application using a public domain air pollution dispersion model, the Industrial Source Complex 3 (ISC3).

A total of 440 subjects were represented in the interviews, including 324 (73.6%) who reported symptoms possibly or probably related to chloropicrin exposure. Ocular symptoms were present in 302 (93.2%) of the symptomatic cases. Nonocular (usually systemic or respiratory) symptoms occurred in 170 cases (52.5%), but occurred significantly more frequently in residents who lived within 0.46 miles of the application site. Air-modeling showed a plume of chloropicrin in the affected neighborhoods, with estimated 1-h TWA (time-weighted average) air concentrations between 0.15 and 0.025 ppm.

Ocular, respiratory, and systemic symptoms on the evening of October 5, 2005, corresponded to a plume of chloropicrin, with estimated concentrations as high as 0.15 ppm, in the community of Salinas, California. Cases occurred between 0.36 and 2.89 miles from the application site. Use of irritant agricultural fumigants near residential neighborhoods can produce a risk of illness for distances more than 2 miles from the site of application. Air modeling is useful for evaluating the relationship between possible exposures and community symptoms.