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Chinese Drywall
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Environmental Pollution
EXPOSURE

Defective Chinese Drywall

Defective Chinese drywall is a drywall that generates discernable negative effects (such as emitted sulfur fumes creating rotten-egg odors and/or corrosion of electrical wiring and malfunctioning of electronic equipment within a home). Yet, not all Chinese-made drywalls are defective. Yet, some of the Chinese drywall may become defective due to changing environmental conditions. Thus, few questions arise:

  • What contributes to defective Chinese drywall?
  • Do any factors influence or induce a drywall to be defective other than its composition and structure?
  • How can one know if a drywall can become defective if no effects are discernable at the current time?

In order to provide answers and better understand defective Chinese drywall issue, let us review what drywalls are, their composition, observed environmental factors which increase the negative effects of defective drywalls, along with the up-to-date noted differences between defective and non-defective drywalls.

Definition. Chinese drywalls are construction materials made in China that were imported in the U.S. due to the shortage of domestic supply of drywall materials during the housing construction boom of the 2000’s (especially after 2004 and reaching a peak in 2006 following the series of destructive Gulf Coast hurricanes). Drywalls are usually made of gypsum which is calcium sulfate dihidrated (CaSO4 x 2 H2O). Gypsum is obtained from either natural minerals (e.g., from open pit mines) or synthetic materials such as fly ash (usually from coal power plants). Thus, based on its origin, gypsum may contain a series of trace components (e.g., metals, minerals such as pyrite, and organic matter) in various proportions, which ultimately dictates its properties and potential for becoming defective or not. Additionally the form of sulfur is very important: any sulfur present in other forms than the sulfate (which is the basic component of gypsum) may be less stable and could react with other elements to produce off-gassing (the fumes with a rotten-egg smell).

Observed Differences in Composition of Defective versus Non-Defective Drywalls

The main observed differences between the toxic Chinese drywall and U.S. drywalls (generally non-defective) are synthesized below.

Based on a recent U.S. EPA study (2009) which tested 2 potentially defective Chinese drywalls and 4 U.S. drywalls:

  • Sulfur was found in the tested potentially defective Chinese drywalls (at 83 and 119 mg/kg) while it was absent from the tested U.S. drywalls (below the detection limits of 8.23 mg/kg);
  • Iron was found at various concentrations in the tested potentially defective Chinese drywalls (1,390 and 1,630 mg/kg) as compared to the tested U.S. drywalls (841-3,210 mg/kg).
  • Strontium was detected in the tested potentially defective Chinese drywalls in higher amounts (2,570 and 2,670 mg/kg) than in the U.S. drywalls (244-1,130 mg/kg)
  • Two organic compounds associated with acrylic paints were found in the tested potentially defective Chinese drywalls only.
  • The amount of total organic compound was higher in the tested potentially defective Chinese drywalls (except for one of the four tested U.S. drywalls).

Other studies (Rosen , 2009; EMSL, 2009; Columbia Analytical, 2009) pointed out that:

  • Defective Chinese drywalls were reported to contain pyrite (FeS2), which is usually avoided in building materials due to the risk of collapsing.
  • It has been reported that sulfur based fungicides were used in the imported potentially defective Chinese dry walls in order to prevent mold and bacteria growth during shipping. Fungicides were probably not used in U.S. made drywalls.
  • Recently, it has been reported the presence of naturally occurring allotrope of elemental sulfur in the defective Chinese drywalls.
  • From structural point of view, defective Chinese drywalls were reported to have a lower fiber content and variable air void sizes (but in general smaller in size) as compared to U.S. drywalls

Responses to the questions above may now be provided:

Question

Response

What contributes to defective Chinese drywall?

Its chemical (presence of certain trace elements) and physical structure (fiber content &void sizes) + Environmental factors (especially climate)

Do any factors influence or induce a drywall to be defective other than its composition and structure?

Yes, it was reported more in states with humid and hot climate (such as Florida and Louisiana)

How can one know if a drywall can become defective if no effects are discernable at the current time?

Through laboratory testing in controlled conditions - Please read more about lab tests of chinese drywall

The Knauf brand was confirmed in some cases of defective Chinese drywall products. However, other Chinese brands may also be associated with defective Chinese drywall. This is why accurate brand identification is required. Additionally, due to the high reported variability of Chinese drywall problems, the production batch of the defective Chinese drywall may need to be determined, too.

Once a defective product is identified, homeowners should consult an environmental attorney. The environmental lawyer may decide which are the best options for damage recovery, including pursuing class actions or individual lawsuits. You are welcome to  contact environmental pollution centers for a free consultation in this respect.

References Cited
Columbia Analytical. 2009. Columbia Analytical Develops Protocol for Testing Corrosion and Odor in Chinese Drywall. June 1, 2009.
EMSL Analytical, inc 2009. Chinese Drywall Emitting Strange Odors and Causing Corrosion on Copper-Bearing Materials Reported. Published Jan. 9, 2009.
Rosen, G. 2009. Chinese Drywall Q & A Ver 3.0 Health Allert.
U.S. EPA. 2009. Drywall Sampling Analysis. Environmental Response Team, Edison New Jersey, 08837.
Letter to Ms. Lynn Wilder, Agency for Toxic Substances and Disease Registry, Dept. of Homeland Security, Atlanta, GA, May 7, 2009.