During 2006 and 2007, a large amount of drywall was imported from China which was used throughout the south east and southern coastal areas of the United States. The need to import this drywall was in part due to the high demand following the damage caused by Hurricane Katrina.
Soon after the installation of this Chinese imported drywall, home owners noticed and complained about foul odors within their new or remodeled or repaired homes. There were also complaints that metals within these homes and buildings were corroding unexpectedly.
The apparent cause of the odors and metal corrosion incidents was the result of drywall imported from China which had a high sulfur content and was emitting sulfurous gas. This immediately gave rise to serious health concerns. In fact, the drywall was found to have emitted volatile sulfur compounds which included hydrogen sulfide, and all of which are linked to serious health issues. Some of the health issues related or noted in the Chinese drywall cases include sore throat, eye irritation, cough, shortness of breath, chest pain, and nausea. Long term exposure, over a period of weeks, is believed to cause chronic fatigue, insomnia, loss of appetite, dizziness, irritability, headaches, memory loss, skin, difficulty breathing, persistent cough, bloody noses, runny noses, recurrent headaches, sinus infection, and asthma attacks.
The questions one might ask is: Why did the Chinese drywall cause concerns in the USA and not in China? The answer seems to be that in the US homes are built in such a manner as to allow less air infiltration than in China. Essentially they are tighter houses than in China. The typical Chinese home has more air infiltration and as a result has more opportunity for the gases to be “washed” out by recirculating fresh air.
Some of the issues included in the corrosion aspects of the drywall emissions were related to pipes and wiring. It was found that the drywall was believed to be corroding plumbing pipes and electrical wiring as well as other non-structural devises in the home such as appliances.
Currently there are several lawsuits underway in the US related to this situation. The drywall is identified with in markings showing the origin as China including simple “Made in China” markings.
Most of the issues which have arisen with the Chinese drywall have been in the warmer and more humid parts of the US, notably the Southeast. A Wiki reference shows that the cases filed are concentrated in these states by percentage – Florida (59%), Louisiana (20%), Mississippi (6%) and Alabama (5%).
Knauf Plasterboard Tianjin Co. Ltd was the primary exporter of the Chinese drywall involved in these problems. There are a number of other Chinese manufacturers which may have exported drywall to the US as well. It has been reported that the shipment of Chinese drywall with the sulfur emission problem has exceeded 500,000 pounds of drywall. While this is substantial, it is only a small part of the average US production of drywall which is 15,000,000 pounds. It is worth noting here that larger retails often avoided selling the imported drywall. Companies such as The Home Depot and Lowe’s have indicated that they sold no drywall which had been imported from China.
In some cases, chemical emissions are found in some USA made drywall, but apparently at lower levels. Lab tests were done comparing US made drywall to imported Chinese drywall. These tests suggest that there are high emissions of harmful sulfur compounds release by the Chinese drywall. The problems have been attributed to the use of fly ash in the Chinese drywall. It degrades in the presence of heat and moisture. While drywall made in the US also uses fly ash, the process in the US results in a cleaner finished drywall.
The most important issue for you as a homeowner, business owner or purchasing agent is to work with a reliable drywall contractor. Ask them to give you the name of the manufacturer of the drywall they will be using for your job. It is fair to assume that because of the issues related to Chinese drywall it is highly unlikely that it would be used on jobs in this country at this time.