Chinese Drywall refers to defective or tainted drywall imported from China from 2001 to 2007 which emits sulfur gases which usually (but not always) creates a noxious odor and corrodes copper and other metal surfaces, thereby damaging your air conditioner, electrical wiring, copper plumbing, appliances and electronics. Chinese drywall can also cause adverse health effects, although experts disagree whether these effects are merely irritants or present a more imminent or chronic health hazard. Not all drywall manufactured in China is defective.
WHAT IS THE SOURCE?
While the material source of the problem is known, a complete understanding of the cause of the problem remains unknown. Initially, the most common theory was that the drywall was manufactured in gypsum mines in China which used fly ash, a waste material that is a byproduct from power plants using coal. Samples of Chinese drywall tested by United Engineering, however, consisted of 5-15% organic material, which contradicts the theory that Chinese drywall was made of waste from coal fired power plants. Some now believe that the tainted drywall from China comes from mined gypsum, not synthetic gypsum which is made from coal ash. Mined gypsum contains high levels of strontium, which is visible as inclusions in electron scanning microscopy.
Another theory is that Chinese drywall contains bacteria (possibly from the water source used to manufacturer the drywall) which is degrading iron and sulfur compounds to produce sulfur odors, although one of the CPSC‘s report disputes this theory.
To date, Chinese manufacturers have yet to disclose the chemicals put into their drywall or the manufacturing processes. See China Plays Tug-of-War With U.S. Inspectors Over Drywall
IS THE DRYWALL DANGEROUS?
There is no question that the gasses emitted from Chinese drywall corrode copper and metal surfaces. Corrosion of electrical wiring may hamper the effectiveness of smoke detectors, which clearly presents a safety concern. Low level arcing has also been observed in some homes with Chinese drywall, which could cause an electrical fire. See CPSC Drywall Chamber Test Results. The CPSC now reports that there are no acute or long-term electrical safety events, such as smoking or fire. Some disagree, particularly since there have been no long term studies.
Chinese drywall was found by Lawrence Berkley National Laboratories to emit hydrogen sulfide up to 100 times greater than non-Chinese produced drywall. Hydrogen sulfide is a hazardous gas which, in high concentrations, can be fatal. There is also a strong association between hydrogen sulfide and metal corrosion. See CPSC list of drywall manufacturers whose drywall has been found to emit the high levels of hydrogen sulfide.
Analytical testing of Chinese drywall samples have revealed strontium sulfide, although there remains disagreement regarding whether strontium is a valid marker for Chinese drywall. See Public Health Statement regarding Regarding Health Effects. See also, EPA Drywall Sampling Analysis dated May 7, 2009).
According to Dr. Patricia Williams, a University of New Orleans toxicologist, highly toxic compounds have been found in Chinese drywall and prolonged exposure to these compounds can cause serious problems. Strontium sulfide may be dangerous to developing children; it affects bone growth. Chronic exposure to these gases may affect the central nervous system (including visual and sensory changes), cardiovascular system, eyes, kidneys, liver and skin. Infants, children, the elderly and infirm (particularly those with heart and lung disease and diabetes) and pets may have an increased vulnerability to these gases and the particulates that are released from the drywall.
To date, the Florida Department of Health still maintains that the levels found in Chinese drywall are not high enough to present “an imminent or chronic health hazard at this time.” Many experts disagree.
WHAT ABOUT CROSS-CONTAMINATION
Chinese drywall is very friable, which means it is in a state where small particles can easily become dislodged with little friction. For this reason, even after Chinese drywall is removed, the toxic drywall particulate may remain unless property removed. Further, the particulate from Chinese drywall may invade and adhere to other building materials in the home’s structure and personal objects within the home. Thus, cross-contamination should be factored into any remediation protocol. According to the Florida Department of Health, it is possible for gasses to absorb and re-emit from porous materials such as drywall and fabrics. The effectiveness of cleaning these materials is unknown. It is also unknown there is any effect on concrete and lumber. It is possible for gasses to absorb and re-emit from porous materials such as drywall and fabrics. The effectiveness of cleaning these materials is unknown. It is also unknown whether there is any effect on concrete and lumber.