California Department of Public Health logo: three likenesses of people colored blue, green, and orange  
Last Edited: 3/4/2003

What is Stachybotrys chartarum (also known as Stachybotrys atra)

This is one of many types of black mold that may grow on water-damaged building materials. This mold requires a lot of water or moisture to grow, so finding it indoors indicates some significant moisture accumulation problems. It only grows on materials with high fiber and low nitrogen content, such as paper (including wallpaper and the paper covering of gypsum wallboard), wood or jute (frequently used for the backing of older carpets). This mold does not grow on shower tile or plastic. In the outdoor environment it is found in soil, rotting hay and leaf debris. This mold, among others, may produce mycotoxins - chemicals that discourage growth of other microorganisms and that may also cause health problems in people. However, the production of mycotoxins may depend on a variety of factors and the presence of this mold does not necessarily indicate the presence of mycotoxins.