A 2017 survey conducted by the National Safety Council found employee use of prescription drugs on the job had affected a majority of employers. The most significant effect was absenteeism or missed work (reported by 39 percent of respondents) followed by impaired or decreased job performance (reported by 29 percent) and safety concerns, such as injuries or near misses (reported by 15 percent).

However, a more recent report from December 2018 is cause for even more concern—the use of non-prescription drugs in the workplace. A new report published by Quest Diagnostics notes such drug use among the U.S. workforce is increasing at an alarming rate. While the utility industry has among the lowest rates of drug use by employees (2.8 percent positivity rate in 2017), other industries are not faring as well.

"Our analysis suggests that employers can't assume that workforce drug use isn't an issue in their industry," said Barry Sample, Ph.D., senior director, science and technology, for Quest Diagnostics. "In fact, drug test positivity in the majority of industry sectors analyzed is growing."

The most commonly detected substance in the workplace is marijuana. The top five industry sectors in terms of year-over-year increases of marijuana use are transportation/warehousing (a 33.3 percent increase between 2015 and 2017), other services (a 33.3 percent increase), construction (a 26.7 percent increase), wholesale trade (a 23.5 percent increase), and manufacturing (a 23.1 percent increase).

In all industry sectors, amphetamine positivity rates grew significantly between 2015 and 2017. Methamphetamine positivity rates in specific were highest in the construction sector, with a 15-percent increase between 2015 and 2017.

"Methamphetamine, which is a prescription drug, but is most often associated with illicit use and production in clandestine laboratories, is a potent version of amphetamine that has more harmful effects on the central nervous system and has a high potential for misuse," the report notes.

In the Manufacturing sector, methamphetamine positivity increased by 27 percent between 2015 and 2017.

In addition, the construction sector ranked highest among all industries for cocaine positivity (0.41 percent in 2017), more than 33 percent higher than the rates in the U.S. workforce in general.

"This new analysis suggests that an increasing number of applicants and employees across various industries may be misusing dangerous drugs," said Kimberly Samano, Ph.D., scientific director for Quest Diagnostics.