Reporting from Los Angeles and Wuhan, China — The final years of the U.S. housing boom and a disastrous series of Gulf Coast hurricanes created a golden opportunity for Chinese drywall manufacturers. With domestic suppliers unable to keep up with demand, imports of Chinese drywall to the U.S. jumped 17-fold in 2006 from the year before.
That imported drywall is now at the center of complaints of foul odors seeping from walls. Hundreds of homeowners, most in Florida, have also reported corrosion to their air conditioners, mirrors, electrical outlets and even jewelry.
State and federal authorities have traced the problems to Chinese-made drywall but haven't yet fully determined the causes. Some Chinese experts, however, suspect that the culprit is a radioactive phosphorus substance -- phosphogypsum -- that is banned for construction use in the U.S. but has been used by Chinese manufacturers for almost a decade.
Copies of Chinese customs reports obtained by The Times, along with interviews, indicate that drywall made with phosphogypsum was shipped to the U.S. in 2006 by at least four Chinese-based manufacturers and trading firms.
The health risk of phosphogypsum is uncertain, but industry specialists say they are troubled by its widespread use and the possibility it was exported, especially in light of recent incidents in which other Chinese imports such as pet food, toys and candy were found to be contaminated with toxic or unsafe substances.
"Considering the fact that phosphogypsum can cause corrosion, something should be done," said Ding Dawu, a geoscientist and an authority on gypsum processing in China. "Right now," he added, "there are no complaints [in China] because most people don't know much about gypsum board and there are no standards against it."
The Times contacted about 20 Chinese-based companies involved in making or selling drywall. Most of them declined to comment about their overseas business. Others offered conflicting answers or said they didn't know whether their drywall contained the banned substance.
One exception was Beijing Building Materials Import & Export Co. It was among at least 10 trading firms that exported drywall to the U.S. in 2006, according to the customs reports, which were provided by an industry source and confirmed by the Chinese government's statistics compiler in Hong Kong.
