http://www.newsobserver.com/2010/10/03/717591/unc-system-facilities-are-in-a.html#storylink=misearch
This story just scratches the surface of what is really going on with the HVAC systems on NC State's campus. Many, many buildings are spreading mold and making people very very sick. Some buildings are new, some buildings are old that are having problems. Basically there is just no excuse for the lack of maintenance and lack of budget to maintain these buildings. If you are going to build it, you must maintain it, and historically preserving a building full of mold, is just wrong, its just wrong.
Water is essential to live, but where there's water damage in buildings the mold growth could be rampant. Mold can be visibile, mold can be hidden. Mold growth can make people very sick. It is alarming how many people get sick every year from mold exposure yet don't even know what is causing their illnesses. Luckily I found a good Dr.! Search out the doctors from the "Mold Warriors" book by Dr. Ritchie Shoemaker to find the ones that are good in your state.