The collapse of the St. Francis Dam in California killed more than 500 people in 1928, and a school explosion in Texas killed approximately 300 people in 1937. Both incidents led to the licensing of professional engineers in these states for the protection of the public health, safety, and welfare. In 1907, Wyoming became the first state to license engineers, and in 1947, Montana became the 50th state. Before the enactment of those state licensing laws, virtually anyone could call themselves a professional engineer or offer engineering services to the public.