Bureau of Labor Statistics (BLS) describes careers and has the answers to the following:
"The O*NET Program is the nation's primary source of occupational information. ...Central to the project is the O*NET database, containing hundreds of standardized and occupation-specific descriptors on almost 1,000 occupations covering the entire U.S. economy. The database, which is available to the public at no cost, is continually updated from input by a broad range of workers in each occupation."
Click for the O'Net occupational definition of 33-2011.00 Firefighters
Click for the O'Net occupational definition of 33-2021.00 Fire Inspectors and Investigators