Yesterday the U.S. EPA announced new label changes to aluminum and magnesium phosphide pellets for pest control. A summary of these changes is posted online at http://www.epa.gov/oppsrrd1/reregistration/alphosphide/aluminum-magnsm-phos-fs.html
The Salt Lake City Tribune today also reported the action and provides more background on the deaths of the two girls whose front yard was treated with phosphine to control voles. The deaths, which occurred this past February, were not the first phosphine deaths caused when the product has been used in or around homes. Many of you may remember that in 2007 a 4-year-old Lubbock Texas girl died in after a phosphine generating pesticide was used in the home, apparently for cockroach control. That application was made by family members after they purchased the tablets from someone illegally, and in blatant violation of the pesticide label, and Federal pesticide laws. Also in Texas, in 2006 27 horses died after a farmer attempted to fumigate a grain bin with phosphine. It is generally recommended to wait 10 days between application and when treated feed is presented to animals, but in this case Texas A&M researchers report that the horses fed on the treated grain within 14 hours of application.
Phosphine is a toxic gas that is released when aluminum or magnesium phosphide is exposed to air or water. In the U.S. it has labels for both commodity fumigation and vertebrate control, and is considered a Restricted Use Pesticide. It is manufactured for pest control by both Degesh America and United Phosphorus. Current label instructions require at least a 15 foot buffer between a treated rodent burrow and an occupied structure. It's unclear whether that buffer was followed in the Utah case, but the new EPA label requires a 100 foot buffer. According to a February article in the Salt Lake City Tribune, the EPA recommended the wider buffer but was frustrated in its efforts in 1998 by intense lobbying from the tobacco industry, which frequently relies on phosphine fumigants in tobacco manufacture.
Such tragedies underscore the importance of following pesticide laws when selling, distributing, and applying any pesticide. They also illustrate the importance of basing pesticide regulation on good science and thoughtful consideration of risks rather than political pressure.
PMPs and anyone in the pest control business should welcome the EPA restrictions on use of phosphine around structures. I know that in general our pest control industry uses very little phosphine gas in urban areas, but this should be a reminder to all--dealers, distributors, service managers in charge of pesticide inventories, and PMPs--to treat these products as highly dangerous and to secure them with the highest security from theft and misuse. Our current regulatory system is not perfect, but it is good; and we should all respect and follow it.