Occupational Safety and Health Case and Demographic data

Scope and coverage

Besides injury and illness counts, survey respondents also are asked to provide additional information for a subset of the most serious nonfatal cases logged, namely, those that involved at least 1 day away from work, beyond the day of injury or onset of illness. Employers answer several questions about these cases, including the demographics of the worker disabled, the nature of the disabling condition, and the event and source producing that condition.


Most employers use information from supplementary recordkeeping forms and State workers' compensation claims to fill out the Survey's "case form;" some, however, attach those forms when their narratives answer questions on the case form, an option the Bureau offers to help reduce respondent burden. Also, to minimize the burden of many larger employers, sampled establishments projected to have large numbers of cases involving days away from work receive instructions on how to sample those cases.

The Bureau developed a new Occupational Injury and Illness Classification System to permit standardized and uniform coding of the injury or illness involving days away from work and the way it occurred. The major code structures of that system are:

  • Nature of injury or illness, or the principal physical characteristic of the worker's injury or illness;
  • Part of the body directly affected by the injury or illness;
  • Source of injury or illness, that is, the object, substance, bodily motion, or work environment which directly produced or inflicted the injury/illness;
  • Event or exposure, or the manner in which the injury or illness was inflicted or produced; and
  • Secondary source, or the object, substance, or person that generated the source of injury or illness or that contributed to the event/exposure.


To better understand how this topology is used, consider the case of a worker sustaining a deep cut on his chin after being struck by a piece of wood that flew off of a jammed power saw. The nature of this injury is cut, while the part of body, of course, is the chin. The piece of wood is the source of the injury; the power saw is the secondary source; and the event is struck by flying object. In this instance, the safety problem associated with power saws would have gone unrecognized without a code for secondary source.

The survey also collects information from employers on the occupation and certain other demographic characteristics of workers sustaining an injury or illness resulting in days away from work. Two required elements—gender and age of the injured—are almost always readily available from records. Two others—race and ethnic origin and length of service with employer—are optional elements because they are not required in Federal recordkeeping and may not be available on State workers' compensation forms. Cases for which these data elements are not reported are tabulated separately.

Occupation—another required survey element—was coded from job titles supplemented at times by employer answers to questions about how the incident occurred. The 1990 Occupational Classification System, developed by the Bureau of the Census, was used to slot injured workers into one of several hundred individual occupations, such as registered nurse, licensed practical nurse, or nursing aide/orderly. Each individual occupation is tied to one of six major occupational groups: for example, registered nurse belongs to the major group "managerial and professional specialty;" licensed practical nurse, to the group "technical, sales, and administrative support;" and nursing aides, to the group "service occupations." The other three major groups were "farming, forestry, and fishing;" "precision production, craft, and repair," which includes construction trades; and "operators, fabricators, and laborers," such as textile sewing-machine operator, truck driver and stock handler/bagger.

In addition to publishing injury and illness counts, rates, and characteristics, the Bureau estimates injury and illness severity, using information provided by employers on the number of days away from work to recuperate from each disabling condition. If, as a result of injury or illness, the employee did not return to work by the end of the survey year, then the employer reports an approximate return date - which in conjunction with the date of injury or illness - yields an estimate of days away from work for that case. Two basic measures of severity are used with the characteristics of days away from work cases:

  • Median days away from work, the point at which half the cases have a longer duration and half a shorter one; and,
  • Distribution of cases involving various lengths of absences from work, ranging from 1 or 2 days to 31 days or longer.

Summary data on nonfatal counts and rates for all recordable injuries and illnesses and separately for those with and without lost workdays are issued in December of each year. The following April, summary data are issued on the characteristics of workers sustaining days away from work injuries and illnesses and how those incidents occurred. Other regular publications presenting annual survey information include a summary of counts and rates by detailed industry and a comprehensive bulletin on counts, rates, and characteristics.


Data collected or maintained by the Bureau of Labor Statistics under a pledge of confidentiality shall be treated in a manner that will assure that individually identifiable data will be accessible only to authorized persons (BLS employees) and will be used only for statistical purposes.


Last Modified Date: October 16, 2001