There are several reasons to perform drug testing on workers. One reason relates to safety concerns for others if the worker is impaired. Another is to hold certain profession to a higher standard in order to maintain public trust.
Issues that must be distinguished:
(1) intoxication at work
(2) drug usage when away from work, with look-back period usually 1-3 days (longer for marijuana) for many drugs of abuse
(3) addiction
One of the largest groups considered safety-sensitive is transportation, including:
(1) airplane and helicopter pilots
(2) train engineers
(3) boat captains and mates
(4) truck drivers
(5) other commercial drivers
Other occupations that are safety-sensitive:
(1) police or public safety officer
(2) doctors and advanced practice nurses
(3) first responders and ambulance drivers
(4) crane operators and other construction equipment operators
(5) waterway controllers (bridge, lock, etc)
There are also arguments to include other measures of fitness to practice in these occupations, including screening for sleep apnea, visual acuity, etc.
