Exposures from indoor spraying of chlorpyrifos pose greater health risks to children than currently estimated.

Recent findings of indoor exposure studies of chlorpyrifos indicate that young children are at higher risks to the semivolatile pesticide than had been previously estimated [Gurunathan et al., Environ Health Perspect 106:9-16 (1998)]. The study showed that after a single broadcast use of the pesticide by certified applicators in apartment rooms, chlorpyrifos continued to accumulate on children's toys and hard surfaces 2 weeks after spraying. Based on the findings of this and other research studies, the estimated chlorpyrifos exposure levels from indoor spraying for children are approximately 21-119 times above the current recommended reference dose of 3 microg/kg/day from all sources. A joint agreement reached between the U.S. Environmental Protection Agency and the registrants of chlorpyrifos-based products will phase out a number of indoor uses of the pesticide, including broadcast spraying and direct uses on pets. While crack and crevice treatment of insects (such as cockroaches and termites) by chlorpyrifos will still continue, it appears prudent to explore other insect control options, including the use of baits, traps, and insect sterilants and growth regulators. To ensure global protection, adequate dissemination of appropriate safety and regulatory information to developing regions of the world is critical, where importation and local production of chlorpyrifos-based products for indoor uses may be significant.