Concerns CONCERNS Lead Ingested or inhaled this toxic substance can cause serious health problems. Mold Hidden inside your walls and under your floor could be a toxin that is making you sick. Asbestos Highly versatile and once highly valued and well used material. A known cause of cancer. Stucco There could be a serious problem lurking behind that facade. Chinese Drywall Defective and contaminated drywall that is polluting buildings by off-gassing sulfide and disulfide compounds. Polybutylene Pipe A solution that turned into a real problem.