Chinese drywall controversy is a health and safety issue involving defective drywall manufactured in China and imported by the United States starting in 2001.Drywall is a common building material typically made of a layer of gypsum-based plaster pressed between two thick sheets of paper, then dried in a kiln. Foreign drywall was imported by the United States during the construction boom between 2004 and 2007. Importation was further spurred by a shortage of American-made drywall due to the rebuilding demand of nine hurricanes that hit Florida from 2004 to 2005, and widespread damage caused along the Gulf Coast by Hurricane Katrina in 2005. An analysis covering drywall imports since January 2006 showed that more than 550 million pounds of Chinese drywall was brought into the United States since then, enough to build 60,000 average-sized homes.
Homeowners alleging that they installed contaminated drywall have reported numerous incidents of corroding copper and other metals in their homes. The Florida Department of Health advised homeowners worried about tainted drywall to check copper tubing coils located in air conditioning and refrigeration units for signs of corrosion caused by hydrogen sulfide, as these are usually the first signs of the issue. Under normal circumstances, copper corrosion leaves it a blue/green or dark red color, whereas corrosion as a result of hydrogen sulfide exposure leaves a black ash-like corrosion. Homeowners who have verified that their home contains contaminated Chinese drywall are advised to replace any suspect drywall, as well as any potentially damaged copper electrical wiring, fire alarm systems, copper piping, and gas piping.
The CPSC has been investigating claims in Florida for more than a month, according to commission spokesman Joe Martyak. He would not confirm whether CPSC is checking other states or reveal how many cases it is probing. The Florida complaints generally involve homes built or renovated in 2005 and 2006, when a building boom and post-hurricane reconstruction caused a U.S. drywall shortage that spurred builders to turn to imports, Martyak said. The allegations come after a number of recent safety problems with other Chinese exports, ranging from toys to pet food.
Officials are looking into claims that Chinese-made drywall installed in some Florida homes is emitting smelly, corrosive gases and ruining household systems such as air conditioners, the Consumer Product Safety Commission says. The Florida Health Department, which is investigating whether the drywall poses any health risks, said it has received more than 140 homeowner complaints. And class-action lawsuits allege defective drywall has caused problems in at least three states — Florida, Louisiana and Alabama — while some attorneys involved claim such drywall may have been used in tens of thousands of U.S. homes.
The exemptions reveal that Chinese drywall was only used in Southwest Florida between 2004 and 2007; the four year span of recovery from Hurricane Charley and Wilma and the building boom. If you break it down by percentage, in Lee County only .44% of the single family homes and condos are infected and only 2.5% from the boom building years. In Charlotte County the percentage of homes infected is .27% and in Collier County it is .06%. The toxic material causing all the problems is only found in the 1/4 inch drywall used in residential construction. The 1/2 inch drywall used in commercial buildings is safe.
Lab comparisons of Chinese- and American-made drywall show significantly higher levels of pyrite in the Chinese material. This suggests that pyrite oxidation may be the source of the sulfur compounds released by Chinese drywall. The problems have been attributed to the use of fly ash in the drywall, which degrades in the presence of heat and moisture; although United States’ drywall uses fly ash as well, the process used creates a cleaner final product. According to a 2010 laboratory study, one hundred percent of affected drywall samples obtained from homes located in the southeastern United States tested positive for the presence of Thiobacillus ferrooxidans, an iron and sulfur reducing bacterium. Samples of non-contaminated drywall were found to contain only miscible levels of T. ferroxidans.