There’s a drug problem in many Pennsylvania schools, even ones where the signs outside proclaim zero tolerance.

The signs and slogans, in fact, might be contributing to the problem where enforcement is lacking or incomplete. The signs convey to students a cynical notion that adults in charge don’t really mean what they say.

Maybe its not a drug problem as much as an attitude problem — a perception that drug abuse in school doesn’t really matter or that adults look the other way.

An effective purge of drugs will take more than signs and slogans, says state Rep. Anthony DeLuca. The Pittsburgh Democrat’s House Bill 810 would mandate drug screening for all new teachers and other school employees and would apply equally to public and private schools, intermediate units and vo-techs. Contractors, too. Zero exceptions.

DeLuca’s peers agree. Last week, the House voted 182-12 for HB810 and sent it on to the Senate.

In a memo posted on his website, DeLuca explains his inspiration for HB810.

“We do not currently require pre-employment drug testing for our public and private school applicants,” he wrote. “We have strict screening requirements for the hiring of state employees in some jobs, turnpike workers and other public personnel, yet we are negligent with the individuals to whom we entrust our school children.”

The young students are our most valuable asset, DeLuca says, and they’re dependent on the rest of us for protection; yet, by not screening teachers, bus drivers, cafeteria workers, aides and custodians, we entrust our young to individuals who might harbor a potentially dangerous habit.

The bill would amend the existing state code for new school hires, who currently must submit a criminal-background check and a child-abuse clearance with their applications and resumes.

The state code dates back to 1949 — a markedly more innocent era defined by heroes like John Wayne, Joe DiMaggio and FDR. Back then, school teachers guarded their reputations for fear of losing jobs — now-retired teachers drove out of county just to enjoy a drink in a bar without fear of being recognized and vilified by the local gentry.

And certain unsavory topics were never discussed, certainly not in public, but they still happened. Individuals made the same bad decisions and suffered the same addictions, unintended pregnancies, criminal records and other disappointments then as they do now. But in the 1940s, ’50s and ’60s they solved their problems in private rather than post them on Facebook.

Nowadays we’re more open about such things. We draw on the old saying that to err is human and to forgive divine, as if we can expand our divinity by talking away the error. And that’s not a bad thing if the objective of the talk is to overcome the error.

The problem is, openness and empathy get mistaken for tolerance and indifference toward the error, particularly if the error persists, as the error of drug trafficking does in many schools. It confuses young, impressionable students and turns them cynical when the things their adult school leaders say don’t line up with the things they do — or fail to do.

Fortunately, there’s no confusion or inconsistency in a pre-employment drug test. The Senate should have no reservations about backing this legislation.