Last year, the U.S. workforce tested positive for illicit drugs usage at the highest rate in 12 years at 4.2%, according to lab services provider Quest Diagnostics. The rate was 4.5% in 2004.
Quest researchers reviewed more than 10 million samples for its Drug Test Index.
Senior Director of Science and Technology for Quest, Dr. Barry Sample, said the findings showed increased rates for the most common illicit drugs across virtually all drug test specimen types and in all testing populations.
Urine samples showing evidence of cocaine increased by 12% from 2015 in the overall workforce, the fourth rise in as many years. This increase also was measured among safety-sensitive workers including pilots, nuclear power workers, truck and bus drivers.
Positive tests for marijuana use among safety-sensitive workers increased by 9.9% in 2016, which is the largest jump in five years. Eight states, and the District of Columbia, have legalized marijuana for recreational use.
Amphetamines and methamphetamines show up in urine tests about 8% more often in 2016 than in 2015. Quest researches point to prescription drugs such as Adderall as one reason for the steady increase in this area.
Heroin use leveled off in 2016 after four straight years of increases. And positive tests for prescription opiates decreased for the fourth consecutive year.
To read the study, click here.