Stachybotrys chartarum is a greenish black fungus (mold) that grows on material with a high cellulose and low nitrogen content, such as fiberboard, gypsum board, paper, dust, and lint, that becomes chronically moist or water damaged due to excessive humidity, water leaks, condensation, water infiltration, or flooding. S. chartarum may, under specific environmental conditions, produce toxic chemicals called mycotoxins, present in the spores and the hyphae that may become airborne when the fungus dries up and dies. Airborne spores may be drawn into the lungs and cause burning sensation in the mouth, nausea, vomiting, diarrhea and abdominal pain. No lethal cases have been reported.