A US interdepartmental probe has determined that there is no direct link between the chemicals in the Chinese drywalls and the health problems reported by homeowners who used the material.
Drywall is an interior construction material made of gypsum plaster.á It is used globally for the finish construction of interior walls and ceilings.
About 500 million pounds of drywall were imported from China to the United States between 2004 and 2007 when the housing market was booming and the Southeast was rebuilding from Hurricane Katrina. The drywall was produced by Chinese subsidiaries of German manufacturer Knauf Plasterboard Tianjin Co. Ltd.
The executive summary of the findings released Thursday said - The interagency task force on Chinese drywall is releasing today the initial results of several studies that begin to assemble pieces in the overall Chinese drywall puzzle. The investigation continues and additional reports will be released in November.
The U.S. Consumer Product Safety Commission has served as the lead agency within the task force that has also included the U.S. Environmental Protection Agency, the Centers for Disease Control and Prevention/Agency for Toxic Substances and Disease Registry, and the U.S. Department of Housing and Urban Development as well as the Florida Department of Health, the Louisiana Department of Health and Hospitals and the Virginia Department of Health, among others.
To date, nearly 1900 consumers have contacted the CPSC to report problems in their homes. T
The primary issues reported are: 1) corrosion, or blackening, of indoor metals, such as electrical components and central air conditioning system evaporator coils; and 2) various health symptoms, including persistent cough, bloody and runny noses, headaches, difficulty in breathing and irritated and itchy eyes and skin.
Early findings by health officials in Florida found that the gypsum wallboard used in the homes when exposed to high levels of humidity and heat can produce a gas strong enough to corrode copper wiring, pipes and appliances.
But the findings now released say, "The tests did not detect the presence or found only very limited or occasional indications of sulfur compounds of particular interest - hydrogen sulfide, carbon disulfide, and carbonyl sulfide. Concentrations of two known irritant compounds, acetaldehyde and formaldehyde, were detected in both homes with and without Chinese drywall, and at concentrations that could exacerbate conditions such as asthma in sensitive populations. The levels of formaldehyde were not unusual for new homes, however, and were higher when the homes were not air-conditioned."
Next month the results of a 50-home indoor air testing study will be released as well as a preliminary engineering analysis of electrical and fire safety associated with corrosion. The federal agencies involved in this effort are also working to finalize a recommended protocol for in-home testing which will be guided by the methods used to test the various homes to date. A study of long-term corrosion issues, that seeks to simulate decades of exposure and corrosion, will not be completed until June of 2010.