From the Centers for Disease Control and Prevention. Improvements in workplace safety--United States, 1900-1999.
D000062:Accidents, Occupational / Q000401:mortality; D049673:History, 20th Century; D006801:Humans; D008906:Mining / Q000266:history / Q000706:statistics & numerical data; D016272:Occupational Health / Q000266:history; D012449:Safety; D014481:United States / Q000453:epidemiology; D017132:Workplace / Q000266:history