Testing at the Texas A&M University College of Veterinary Medicine and Biomedical Sciences and the Texas Veterinary Medical Diagnostic Laboratory has yielded evidence that the toxic principal responsible for the recent deaths of more than two dozen horses at Carousel Acres Equine Center in Brazos County, Texas, was in all likelihood phosphine gas.

Phosphine is a gaseous product released from a highly toxic fumigant pesticide that was reportedly applied by Carousel Acres to the feed bin to kill weevils. H Richard Adams, DVM, PhD, dean of the Texas A&M College of Veterinary Medicine and Biomedical Sciences, indicated necropsies on three of the horses that died at the Texas A&M veterinary clinic all showed the presence of phosphine gas in their stomach