Acute oral toxicities of wildland fire control chemicals to birds.

Wildland fire control chemicals are released into the environment by aerial and ground applications to manage rangeland, grassland, and forest fires. Acute oral 24h median lethal dosages (LD50) for three fire retardants (Fire-Trol GTS-R, Phos-Chek D-75F, and Fire-Trol LCG-R) and two Class A fire suppressant foams (Silv-Ex and Phos-Chek WD881) were estimated for northern bobwhites, Colinus virginianus, American kestrels, Falco sparverius, and red-winged blackbirds, Agelaius phoeniceus. The LD50s of all chemicals for the bobwhites and red-winged blackbirds and for kestrels dosed with Phos-Chek WD881 and Silv-Ex were above the predetermined 2000mg chemical/kg body mass regulatory limit criteria for acute oral toxicity. The LD50s were not quantifiable for kestrels dosed with Fire-Trol GTS-R, Phos-Chek D-75F, and Fire-Trol LCG-R because of the number of birds which regurgitated the dosage. These chemicals appear to be of comparatively low order of acute oral toxicity to the avian species tested.