Have you read this article?
http://en.wikipedia.org/wiki/LegionellaGoogle for others...they are saying that in cooling tower situations, it may go over 6 km with FATAL results!!! You really need to stop work until you get hese decontaminated. Luckily, it seems that part is easy, 170 degree steam cleaning, or chemical treatment. However, I think you need to have somebody who is experienced in this work with you on making sure there is no risk towards you and other workers. We can talk about it all we want on ECN, but when it comes to death, you need an industrial hygenist or similiar type of person to add his expertise to your situation.
Check out those articles, I actually learned a lot more than I thought I knew about it!
