Horsehair plaster is potentially dangerous because it may contain anthrax spores or asbestos, according to Asbestos Watch and Bricks & Brass. Safe removal of horsehair plaster requires stringent safety precautions.
Horsehair plaster contains dark hairs visible to the naked eye. This is normal and does not indicate the presence of anthrax or asbestos. However, plaster with an abundance of light-colored fibers likely contains asbestos, according to Asbestos Watch.
Disposable gloves, eye protection and dust masks are essential for safe horsehair plaster removal. Covering wounds prevents anthrax spores from entering the body through open skin, as stated by Bricks & Brass.
Brushing or sweeping horsehair plaster dust releases potentially dangerous particles into the air. Vacuuming is a safer alternative.