Acute Inhalation Toxicity of Fog Oil Smoke in the Red-Winged Blackbird, a Size-Specific Inhalation Surrogate for the Red-Cockaded Woodpecker

Abstract : The red-cockaded woodpecker (Picoides borealis) is an endangered species often found on military lands where troop readiness training is conducted. An important component of this training is the generation of obscurant materiel to conduct maneuvers under obscurant cover. Fog oil (SGF-2) is the obscurant most commonly deployed for these purposes. To help assess and manage the impact of fog oil to sensitive wildlife species, such as the red-cockaded woodpecker, we evaluated the acute toxicity and health risk of environmental releases of fog oil to avian wildlife. The red-winged blackbird (Agelaius phoeniceus) was used as a surrogate species for the red-cockaded woodpecker. Wild red-winged blackbirds were exposed to varying airborne concentrations of fog oil. The post-exposure response of the blackbirds was monitored for 28 days. Compared to control birds, no mortality, body weight loss, clinical signs of toxicity, or behavioral abnormalities were observed in any of the fog oil-treated birds. The distribution and severity of gross and histopathological lesions were independent of the fog oil exposures and were typical of those found in wild bird populations. Although respiratory function data were limited, no major respiratory impairment or abnormalities were observed during the exposure or the post-exposure period.