In 1971, the Animal Welfare Act was revised, and compliance by institutions could be achieved through an animal care committee or via AAALAC accreditation. Compliance required adhering to the Guide, the Animal Welfare Act, and an additional set of "Principles for the Use of Laboratory Animals." In 1979, U.S. Public Health Service (PHS) policy took over, requiring an animal care committee for each animal-using grantee institution and expanding the species covered to include all vertebrates. The animal care committee was required to have five members with expertise to regulate animal welfare at that institution, including at least one veterinarian.