I work at an oil and gas company. If a bag of cocaine was found laying around the office, instantly the police would be on site. HR would have emergency drug testing crews on site. 100% of staff and executives plus visitors and contractors would be lined up in the hallways with mandatory drug testing taking place, 100% of everyone peeing in a cup in a police supervised bathroom.
And we do not even have nuclear launch codes in our office.
I worked on an AFB, telecommunications. We weren't allowed to have phones in the building. If you got caught with one you were in big trouble.
If they'd had found a bag of blow everybody would have been subject to what you described, blanket testing. They would've run down the source doing whatever it took.
Of course there were no visitors there. You had to have specific clearance to get in. Even so, something like that would never get "swept under the rug".