The United States began requiring all immigrants to take--and pass--an AIDS test. Aliens applying for legal residency must pay for their own tests. Those who test positive would be denied entry into the United States. No appeal is possible, but waivers could be granted in rare cases when "there is no likelihood of infection of others," said Omer Bangs, Immigration and Naturalization Service's chief legalization officer in San Antonio. The new policy requires anyone applying for permanent resident status to take the test for the acquired immune deficiency syndrome virus, including illegal aliens applying for amnesty under the 1986 Immigration Control and Reform Act.