Abstract: The United States, ranking third among countries in both population and land area, is geographically and ethnically diverse. The 50 states, admitted one at a time to the Union over a period of about 175 years, reflect this diversity in historical development, population, population density, land area, and natural resources. State populations vary by as much as nearly 70 times and state land area by a factor greater than 400. Consequently, industry types, population demographics, and involvement of state governments in occupational health and safety vary among states.