Abstract: On September 26, 2001, Employee #1, a veterinarian for the rescue center, was giving an annual medical examination with a coworker to chimpanzees.. Employee #1 and the coworker placed a female chimpanzee from her cage into a transfer cage that was attached to both the cage of the female chimpanzee and an adjacent cage that housed a male chimpanzee. This transfer cage, a lower and smaller cage than the main cages used for permanent housing, had doors to the two main cages. A blow-pipe was used by Employee #1 to anesthetize the female chimpanzee in the transfer cage. Then Employee #2 gave a needle injection to the same animal. As Employee #1 was leaving the area, the female chimpanzee grabbed his left pant leg through the cage. Employee #1 lost his balance and placed his hand against the cage that housed the male chimpanzee. The male chimpanzee bit off the fifth digit of the left hand. There was loss of the third phalange with skin missing partially on the second phalange of the fifth digit. He was hospitalized.