Only about 60 school districts in the state of Pennsylvania have standard pre-employment drug testing procedures. Drug testing is not required by state law, it is up to the individual school districts to decide whether or not to implement a drug testing program.
FBI fingerprinting and extensive background investigations are a given across the state. Holidaysburg is one district that does perform drug tests on all new applicants. They say they've never had somebody fail the test, but a fail would eliminate that applicant from hire.
The district pays for the drugs tests with their own money and says that they test for the safety of their students. Employees are required to agree to a drug free policy to be good role models for the students.