A 4-percent salary increase for Hawaii school teachers comes with a catch: to win the pay hike, the Hawaii State Teachers Association agreed to allow random drug testing of its members, Education Week reported May 9.

The teachers' contract calls for random testing for alcohol and other drugs. Approved by 61 percent of union members, it has sparked grumbling about the linkage between the salary increases and the testing requirements, as well as predictions of a court challenge.

"I think this is a lawsuit waiting to happen," said teachers' union expert Julia Koppich. "Someone is going to say, 'You don't get to drug test me without probable cause.' " The courts have allowed random drug testing of students and workers in safety-related jobs, but have split on the issue of testing teachers, although some have ruled that teaching falls into the category of "safety-sensitive" jobs.

"We can imagine few governmental interests more important to a community than that of insuring the safety and security of its children while they are entrusted to the care of teachers and administrators," the 6th U.S. Circuit Court of Appeals ruled in one case.

But Roger Pilon, vice president of legal affairs at the Cato Institute, said that just because teachers stand in for parents during the day doesn't mean they should be subject to drug testing. "Then why not test the parents?" he asked.

The Hawaii drug-testing provision came after a number of school employees were arrested on charges of using or selling illicit drugs.