The use of pakalolo in the workplace rose to 2.9 percent from 2.5 percent year-over-year in the last quarter of 2018, following the opening of the state’s first medical marijuana dispensaries.

Diagnostic Laboratory Services Inc., which measures workplace drug use using a quarterly sample that typically includes between 7,000 and 10,000 drug tests, said opiate use fell to 0.17 from 0.24 percent, while the use of cocaine declined to 0.4 percent from 0.5 percent and 0.7 from 1.1 percent for amphetamines.

The use of synthetic urine — commonly used to mask drugs — remained unchanged at 1.2 percent.

“It is kind of alarming that you would show up at a workplace drug test and basically 5 percent get it wrong,” said Steven Brimmer, DLS scientific director of toxicology, adding that he doesn’t “have a clue” as to why most drug use has decreased over the past year. In general, there is about 4.5 percent to 5 percent of workers test positive for drugs in workplace testing, he said. “Amphetamines and cocaine both have gone down over the last year. (But) this is only in the people that do workplace testing. It’s not the general population. It’s a small percentage of the population.”

He said it’s unlikely the opening of marijuana dispensaries has affected workplace drug use.

The first of eight cannabis retailers, Maui Grown Therapies, opened in August 2017, followed by Aloha Green Apothecary in Honolulu. The other pot retailers include Pono Life Maui and Noa Botanicals and Cure Oahu in Honolulu. In May, Green Aloha Ltd., doing business as Have a Heart, also started sales on Kauai. Big Island Grown (B.I.G.) Dispensaries and Hawaiian Ethos on Hawaii island have also started weed cultivation.