Officials of the Centers for Disease Control and Prevention said zinc phosphide is a readily available rodenticide that, on contact with stomach acid and water, produces phosphine, a highly toxic gas. Pets that ingest zinc phosphide often will regurgitate, releasing phosphine into the air.
"Among the four hospital workers, eight poisoning victims were identified, all of whom experienced transient symptoms related to phosphine inhalation. All four dogs recovered fully," a CDC report said.
"Exposure of veterinary staff members to phosphine can be minimized by following phosphine product precautions developed by the American Veterinary Medical Association. Exposure of pets, pet owners, and veterinary staff members to phosphine can be minimized by proper storage, handling and use of zinc phosphide and by using alternative methods for gopher and mole control, such as snap traps."
In humans, inhalation of high concentrations of phosphine can be fatal because phosphine inhibits oxidative phosphorylation and causes lipid peroxidation damage to cells and tissues, the CDC said.
However, for non-fatal inhalation of phosphine, symptoms usually resolve within 30 days and rarely cause any long-term disabilities, the CDC's Morbidity and Mortality Weekly Report said.