Occupational injury and illness data for coal, metal, and nonmetal mining and for railroad activities were provided by the Department of Labor's Mine Safety and Health Administration and the Department of Transportation's Federal Railroad Administration. Injuries and illnesses logged by employers conform with definitions and recordkeeping guidelines set by the Occupational Safety and Health Administration, U.S. Department of Labor. Under those guidelines, nonfatal cases are recordable if they are occupational illnesses or if they are occupational injuries which involve lost worktime, medical treatment other than first aid, restriction of work or motion, loss of consciousness, or transfer to another job. Employers keep counts of injuries separate from illnesses and also identify for each whether a case involved any days away from work or days of restricted work activity, or both, beyond the day of injury or onset of illness. Occupational injuries, such as sprains, cuts, and fractures, account for the vast majority of all cases that employers log and report to the BLS survey.
Occupational illnesses are new cases recognized, diagnosed, and reported during the year.
The latter illnesses are believed to be underrecorded and, thus, understated in the BLS survey. Survey estimates are based on a scientifically selected sample of establishments, some of which represent only themselves but most of which also represent other employers of like industry and workforce size that were not chosen in a given survey year. By design, most small employers are not selected to participate in consecutive surveys. For each survey, the sample used is one of many possible samples, each of which could have produced different estimates. The variation in the sample across all possible samples that could have been drawn is measured by the standard error, for which a range is shown in most tabulations requested by survey users.