Only 10 percent of employers plan to change their drug-testing policies now that recreational marijuana is legal in Massachusetts, a new Associated Industries of Massachusetts survey shows.

The member survey, conducted by AIM HR Solutions, found that two-thirds of the 52 Massachusetts employers who participated say they drug-test employees or job candidates. Three quarters of the companies that conduct drug tests do so for marijuana (THC).

Kyle Pardo, Vice President of Consulting Services for AIM HR Solutions, said the limited number of companies planning to change their marijuana testing policies reflects widespread uncertainty among employers as legal cannabis impinges on the idea of a drug-free workplace.

“Testing detects the presence of marijuana long after an employee may have used the drug during non-work hours. But there is no clear test to determine whether or not that employee is impaired and may represent a danger to co-workers or customers,” Pardo said.

“It has created a confusing situation for employers.”

Recreational marijuana became legal in Massachusetts in 2016 and retail pot dispensaries began to open throughout the state at the end of last year.

Massachusetts law does not require any accommodation of on-site medical or recreational use of marijuana in any workplace or permit employees to come to work under any controlled substance. A recent Massachusetts Supreme Judicial decision requires employers to address an employee with a medical marijuana card in the same manner as those using any other lawfully prescribed medication.

Adding to the confusion is that employers in some federally regulated industries such as trucking and transportation, as well as many federal contractors are required to drug-test employees. Marijuana remains illegal under federal law.

Pardo recommends that employers make sure their hiring process and progressive discipline policy contain information on the drug testing policy and that applicants and employees sign for and acknowledge their understanding of such processes and policies.