Often called "black mold", stachybotrys chartarum can produce allergens and irritants. If you suspect that you have a mold issue, your best course of action is to make sure you do not disturb it, and get a mold test as soon as you can. We did a mold test in Newtown PA recently. We suspect that they have a mold problem there, and will test to see what types of issues they may be facing. They had a water intrusion several months ago, and the home was not treated for mold at that time. The first step, of testing, will give us more information on how to proceed.