I am running a gravimetric lab that has an air handler to maintain the lab at 22C, 35%RH 24/7. We are in the desert so these conditions are adding humidity to our ambient air. Mold grows continuously inside the unit where the sump and sprayers are. There is a UV light to help with this but I still get lots of mold growth. I’d like to ID the mold or at least find out if it is dangerous to be breathing or not. The mold grows on stainless steel and both in the water and out. The water is extremely cold. I’m adding pictures of some of the mold removed and of the interior of the unit where the mold grows. Unit photos are with the water drained and most mold cleaned out. Note: I don't have a URL for images so I'm not sure how to submit the photos. I would appreciate comments based on the description of the conditions. The mold is black in color, slimy and grows in chunks that can be over half a foot long, several inches wide and 1/2 inch thick.