Proceedings of the Vertebrate Pest Conference

The use of fumigants has been commonly practiced for decades to manage burrowing rodent populations in both agricultural and urban habitats. Stories abound about farmers and ranchers illegally fumigating rodent burrows by inserting toxic gas-producing road flares into burrow openings or by simply piping automotive exhaust into burrows systems. Legal fumigant technology includes incendiary devices such as gas cartridges that produce carbon monoxide, and highly reactive magnesium and aluminum phosphide pellets that produce toxic gasses by reaction with the atmosphere. These devices rely on passive diffusion of the toxic gasses through the burrow system. Recently, products have been introduced to the market that force toxic gasses into burrow systems by using blowers or pressurized gas systems. The effectiveness of fumigation systems where toxic gasses, such as carbon monoxide, are allowed to passively infiltrate burrow systems are limited in their geographical range, and as a result are limited in the potential risk to humans or other organisms. Regardless, these products have traditionally had use restrictions based on the proximity to structures and other inhabited areas. The use of systems where toxic gasses are forcefully blown into burrow systems present a greater hazard potential. This manuscript examines the potential risk, in terms of US EPA Standards, for carbon monoxide exposure; published data on carbon monoxide levels in burrow systems; burrow morphology of various burrowing species; and suggests safe distance standards for burrow fumigation activities conducted around structures and other human-occupied habitats.