[virgil]

GSK appears to have an environmental monitoring program, and presumably a good maintenance program. I wonder how the bacteria got in their cooling tower.

[aposiopetic]

I'm guessing SOPs mandate periodic microbial counts, but not in general for specific pathogens. If total counts (CFUs) are below threshold, everything appears copacetic. When they exceed, you look further to see what is driving up the counts, and in this case it was Legionella pneumophila.

This is just a guess, however.

[headstamp 2]

I would say that with cooling tower water, things can run off the rails very quickly especially in the hot weather.

You are constantly oxygenating “warm” water by blowing air through it while it cascades down through in many cases wooden slats. Its a perfect environment to grow things.

A cooling tower is like a microbe manufacturing plant constantly running 24/7. It also constantly adds in fresh water to replace water that has evaporated thus you have a constantly changing environment for any water treatment regimen to deal with.