Heard of something which may be of some importance regarding the suppliers of Drywall. Apparently China has imported several million Sq ft. Chinese Drywall is emitting excessive amounts of hydrogen sulfide fumes, which can cause extreme irritation, unconsciousness, and even death. In everything that I have read it is basicly in the south eastern concentrating in FL. I believe that the china product has a stamp across it stating that it was manufactured in China.
But the problem might be more far reaching in that China supplies some components to make drywall which is shipped to the US other than a finished product.
Complete story and other publications associated are in the following link.
http://www.newsinferno.com/archives/4628