Black mold

"Black mold" scares people, and the fear is partly fair. Some molds, including Stachybotrys chartarum, can produce toxins called mycotoxins. But CDC says the molds themselves are not toxic or poisonous, and that the color of a mold does not show whether it is more or less dangerous.

CDC also says molds that make mycotoxins should be treated like other molds that grow in a house or workplace. The action is the same: find the moisture and fix it.

This helps you decide. You do not need to know the species to know you have a problem. Dark growth on a wall means water got there. Do not scrub it dry or paint over it.

For larger areas, hire a crew that uses containment and a HEPA vacuum. A written plan beats a guess. Read mold remediation for how the full process works and when to call a professional.