The number of Hawaii workers and job applicants testing positive for crystal methamphetamine decreased from a year ago in the first quarter, according to new drug testing data released Monday.

Honolulu-based Diagnostic Laboratory Services Inc., which tested 5,892 people in the first quarter, said the workplace use of methamphetamine, commonly known as ice, fell to 0.5 percent in the first quarter from 1.1 percent in the year-earlier period, though the biggest decline was in the use of synthetic urine — which dropped to 0.8 percent from 1.5 percent — to avoid the detection of drugs.

“Overall we saw a slight decline in all positives, but the most notable one is the sharp decline in synthetic urine,” said Carl Linden, scientific director of toxicology at DSL, which releases quarterly workforce drug statistics. “We were expecting this as word got out that we can now detect synthetic urine.”

Meanwhile, positive tests for marijuana and opiates remained unchanged at 3 percent and 0.2 percent, respectively. Cocaine use also was essentially flat at 0.2 percent.