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"Chinese drywall" refers to an environmental health issue involving defective drywall manufactured in China and imported to the United States starting in 2001. Laboratory tests of samples for volatile chemicals have identified emissions of the sulfurous gases carbon disulfide, carbonyl sulfide, and hydrogen sulfide. These emissions, which have the odor of rotten eggs, worsen as temperature and humidity rise and cause copper surfaces to turn black and powdery, a chemical process indicative of reaction with hydrogen sulfide. Copper pipes, wiring, and air conditioner coils are affected, as well as silver jewelry. Homeowners have reported a variety of symptoms, including respiratory problems such as asthma attacks, chronic coughing and difficulty breathing, as well as chronic headaches and sinus issues.〔(Imported Drywall and Health - A Guide for Healthcare Providers )〕 The case name of the major lawsuit is MDL 2047, ''In re: Chinese-manufactured Drywall Products Liability Litigation'', a suit in New Orleans. ==Background== Drywall (known as plasterboard in Britain) 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.〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Chinese drywall」の詳細全文を読む スポンサード リンク
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