<P> "Chinese drywall" refers to an environmental health issue involving defective drywall manufactured in China, imported to the United States and used in residential construction between 2001 and 2009--affecting "an estimated 100,000 homes in more than 20 states ." </P> <P> In samples of contaminated drywall, laboratory tests will detect off - gassing of volatile chemicals and sulfurous gases--including carbon disulfide, carbonyl sulfide, and hydrogen sulfide . The emissions worsen as temperature and humidity rise, will give off a sulfuric (rotten egg) odor and will cause copper surfaces to turn black and powdery, a chemical process indicative of a hydrogen sulfide reaction and an early indication of contaminated drywall . Copper pipes, electrical wiring, and air conditioner coils are affected, as well as silver jewelry . </P>

When was chinese drywall used in the us