People with disabilities were the first people the Nazis killed in gas chambers. In 1939, the Nazis set up a program called the T-4 Euthanasia Program. As part of this program, the Nazis sent children and adults with disabilities to hospitals like Hartheim Euthanasia Centre, where they were killed with poison gas. They also killed some children with disabilities right after they were born. By the end of World War II, the Nazis had killed about 275,000 people with disabilities. About 5,000 to 7,000 of these victims were children.