More workers are just saying no, at least by one measure.
The share of U.S. workers testing positive for drugs has dropped sharply since 1988, according to an analysis of millions of drug tests being released Monday by medical-testing company Quest Diagnostics Inc. DGX -0.55%
Positive workplace tests for cocaine and marijuana have gone down sharply over the past two decades. Workers may have gotten more sophisticated when it comes to passing drug tests, however, especially for marijuana, as government studies show that its use is rising.
Meanwhile, data suggest that abuse of prescription drugs is a growing worry for employers.
Quest reviewed more than 125 million urine drug tests administered from 1988 to last year. Overall, 3.5% of samples came back positive last year compared with 13.6% in 1988. The vast majority of tests, around 75% in recent years, were conducted for pre-employment screening. The rest were administered following accidents, after employers suspected drug use or as part of regular testing regimens.
But Quest also found that positive tests for amphetamines, which includes prescription drugs such as Adderall, more than doubled between 2002 and last year. Methamphetamine rates fell after 2005, amid a government crackdown on clandestine labs, but recently have begun to rise again, especially among workers in safety-sensitive industries such as trucking and railroads.
Positive tests for painkillers Vicodin and OxyContin rose 172% and 71%, respectively, from 2005 to last year. The data also show higher levels of painkiller use when testing workers after they have been involved in an accident on the job.
“Even when used under prescription, these drugs can have an impact on workplace safety,” said Barry Sample, director of drug-testing technology for Quest.
Independent studies suggest that 65% to 80% of positive tests for amphetamine and opiate use ultimately are disregarded because the user has a valid prescription for the drug. But the growing problem of painkiller addiction means employers need to be more alert to the possibility these drugs are being abused, Dr. Sample said.
The federal Department of Health and Human Services in a 2012 study found that 8.9% of full-time workers over age 18, and 12.5% of part-time workers, had used illegal drugs—including prescription medications taken for nonmedical purposes—in the previous month. Overall, 68% of the 21.5 million drug users over 18 were employed either full- or part-time.
The Quest data aren’t a proxy for general drug consumption in the U.S. Marijuana use, for example, is on the rise in the general population, according to the 2012 National Survey on Drug Use and Health. The HHS study found that 7.3% of Americans over age 12 smoked marijuana in the previous month, compared with 5.8% in 2007.
That disparity could mean that workers have found more ways to evade or manipulate tests. Labs are experimenting with oral swabs and hair tests to cut down on the number of people who pass tests by substituting someone else’s urine.
Since about 18 months ago, Virginia Tire & Auto randomly has selected 10 employees a month to submit samples. Positive tests have gone down slightly over the period to about 4%, mostly for marijuana. Employees who test positive are fired.
Testing improves safety, quality and the work environment, said Mike Holmes, vice president for the auto-repair chain. It is important for employees “to know the person working side by side with them is going to be reliable,” he said.
Drugs in the workplace have become more complicated lately as some states consider legalizing marijuana use.
As that drug becomes legal, employers may revise their policies and reconsider the purpose of their drug-testing programs, said Ethan Nadelmann, founder of the Drug Policy Alliance, which advocates for looser drug laws. “Ultimately, as an employer, The issue is whether people are impaired in the workplace, not whether someone smoked a joint over the weekend,” he said.
Companies are facing more legal challenges for terminating or disciplining an employee for, say, smoking pot after work hours, according to experts. Workers in federally regulated safety-sensitive industries are prohibited from using marijuana, regardless of state law.
In 1988, Ronald Reagan signed the Drug-Free Workplace Act, mandating that employers in certain industries check current or prospective employees for evidence of drug use.
Many other employers require workers to take drug tests before being hired. Companies have wide latitude to test existing employees. Small companies generally tend to terminate employees who test positive, while larger companies often send such employees for treatment.
“If you fire someone for a positive test, it has more preventive value. But in the long run, what you want to do is help people get into recovery,” said Robert DuPont, former director of the National Institute on Drug Abuse.
For safety-sensitive workers, positive drug tests dropped to 1.6% last year from 2.6% in 1992, Quest found. In the general workforce, the rate fell to 4.1% from 10.3%.
Generally, positive test results are investigated for verification and for whether the employees have valid prescriptions. In pre-employment screening, drug users are simply denied a job, said Mark de Bernardo, director of the Institute for a Drug-Free Workplace, which represents employers on drug-policy issues.
Lauren Weber writes about workplace issues and careers for the Wall Street Journal.