It has become difficult to identify mycotoxin production by indoor molds for many variables, such as (i) they may be masked as derivatives (ii) they are poorly documented and (iii) the fact that they are likely to produce different metabolites on building materials. Some of the mycotoxins in the indoor environment are produced by Alternaria, Aspergillus (multiple forms), Penicillium, and Stachybotrys.[22] Stachybotrys chartarum contains a higher number of mycotoxins than other molds grown in the indoor environment and has been associated with allergies and respiratory inflammation.[23] The infestation of S. chartarum in buildings containing gypsum board, as well as on ceiling tiles, is very common and has recently become a more recognized problem. When gypsum board has been repeatedly introduced to moisture, S. chartarum grows readily on its cellulose face.[24] This stresses the importance of moisture controls and ventilation within residential homes and other buildings.