Reactive drywall, more commonly known as Chinese drywall, was imported from China between 2001 and 2009 due to an American shortage of material. It contained extraneous materials such as sulfur, strontium, and iron. In warmer and more humid climates, this drywall emitted various sulfur gasses that caused copper and other metal surfaces to become black and powdery. This corroded the copper pipes, wiring, and A/C coils in all types of buildings, including homes and condominiums, and caused major damage to air conditioners, electrical wiring, plumbing, appliances, and electronics.

The greatest amount of Chinese drywall was installed in the state of Florida, but it had been confirmed in 42 states. Homes built or remodeled between 2005 and 2008 were considered most at risk and it was estimated that more than 100,000 homes were affected. The gasses emitted by Chinese drywall typically smelled like rotten eggs or ammonia. More importantly, observed blackened corrosion of the air conditioner evaporator coil and of any exposed metals in the home were the clearest signs of sulfur emissions from the material.