When I worked at a nuclear plant the explosives detector (the puffer thing) went off on me one morning. It picked up on TATP. Actually it alarmed on a LOT of people. By the time I was alarmed the guard asked me where I walked on the way in and I told him across the grass between parking lots. He said ok you're good. I stopped once I went through the rest of the security measures and looped back around into the security area (I had complete access) and asked him what was going on. He told me landscapers sprayed early in the morning and their spray had chemicals also used in TATP. He was pretty annoyed because of all the extra work he was having to to and it was slowing down the line, so I told him I'd talk to my boss (who ran all of that equipment) to see what we could do.

All my boss could do was contact the company, ask for any updates to rule out that spray, and ask for a thorough cleaning - but it was enough.

Although I did cyber I also helped the guards a LOT with testing or configuring stuff, helping on their rounds, and just hanging out downstairs where their main monitoring area was. I chatted a lot, asked a bunch of questions to see if I could make anything better, watched the surveillance stuff a lot, and on occasion I'd watch their desk while one went to the bathroom. It came in handy because I often worked well into the early morning hours when they had one person at the desk and a skeleton crew outside.