The Labor Department is turning its attention to the opioid epidemic by scrutinizing government worker use, much to the chagrin of federal employee unions.

Changes adopted by the DOL’s Office of Workers’ Compensation Program will allow the department to closely monitor the amount of opiate-based medications prescribed to federal workers injured on the job. The DOL hopes to reduce the rate of federal employees’ initial opioid prescriptions by 10 percent by 2019 and to cut down on fraud in a...