I don’t know about recent, but when I was a teen I knew people who worked the ramp for both airlines and the airport.
Drug tests were not given.
Based upon what I knew of said ‘people’ they should have been given and should be mandatory today.
My understanding is that if they tested ramp workers for drugs, they'd have no ramp workers.
This guy might have been a foreigner who never drove a vehicle in his home country but now drives around airplanes.