Scientists addressing an early November conference in Tampa, Florida, on defective Chinese drywall have offered a more detailed explanation of why the material produces gases that corrode copper elements in buildings, such as wiring and air conditioner coils. According to reporters who attended the “Technical Symposium on Corrosive Imported Drywall,” a $300-a-head event sponsored by the University of Florida, a leading investigator into the problem says the gas releases can be traced directly to the presence of pure sulphur in the panels.
The Sarasota Herald Tribune says that toxicologist Tom Gauthier of the firm Environ International, hired to study the problem by builder Lennar Homes, has found that the elemental sulphur in the panels reacts with naturally-occurring carbon monoxide in the ambient air to form carbonyl sulphide. The carbonyl sulphide then reacts with moisture and air to produce hydrogen sulphide and carbon disulfide. All three gases have been detected in test chambers and in homes containing the Chinese drywall. And according to Gauthier, Environ was able to stimulate a much faster release of the offending gases by placing the drywall in a chamber rich in carbon monoxide.
Government scientists lag behind Environ’s investigators and other outside researchers, notes the Herald Tribune (”Federal scientists trail others on drywall,” by Aaron Kessler). Consumer Product Safety Commission (CPSC) scientists in a report last month, the paper notes, “were not yet even able to state there was an association between the tainted drywall and the corrosion of copper wires, pipes, air conditioning coils, and other metal components” — even though “Florida, along with a host of private consultants, has long since determined that there is a strong association between the drywall and corrosion.”
Tom Gauthier’s results were corroborated by Michael Tuday, research and development director of California-based Columbia Analytical Services, Inc., and Zdenek Hejzlar, an expert in the environmental and toxic health fields with the Fort Myers office of Engineering Systems Inc., reports the Fort Myers News-Press (”Blame sulphur for drywall woes, experts say,” by Mary Wozniak). “The three scientists, in separate presentations, confirmed that the sulphur interacts with indoor air and other agents, like carbon monoxide, to cause different sulphur compounds to be emitted from the drywall in low amounts. It is enough to cause the drywall’s corrosive effect on air conditioning coils and other metal items in the home, they said.”
The sulphur explanation has the virtue of simplicity — unlike a competing theory that casts suspicion on a possible microbial source of the gas releases. “Some labs say Chinese drywall contains significant amounts of sulphate-reducing bacteria,” reports the Palm Beach Post (”Bacteria, chemical reaction debated as roots of drywall problem,” by Allison Ross). But “the bacteria theory needs a lot of work,” said Florida Department of Health toxicologist David Krause, pointing out that while the drywall may contain bacteria, no connection has yet been established between the bacteria and the sulphuric emissions. On the other hand, if carbon monoxide is the limiting element in the formation of carbonyl sulphide, then according to basic chemistry it would make sense that gases are emitted at a steady rate until most of the sulphur in the material is consumed — subject only to the continued availability of carbon monoxide in the ambient air.
Environ scientists also told the conference that in their view, removing the bad drywall and replacing it with fresh, sulphur-free drywall should eliminate the problem, according to the Sun Sentinel paper (”Rip out Chinese drywall and start over, scientist advises,” by Paul Owens). James Poole, an industrial hygienist with the firm, said, “If you remove it, clean up the debris, ventilate the home and rebuild, there’s no reason you can’t expect success.”
Lennar Homes, which has torn out and replaced the defective drywall in dozens of homes already, refused to comment, the Sun Sentinel reports. But Heather Keith, a lawyer for GL homes, which has replaced drywall in at least 20 units, told the paper that customers were “happy” with the fix, saying, “There are no reported or ongoing health or odour issues. I’d be surprised if the scientific community would say that the extensive repair that involves the complete removal of the interiors of a house is premature or insufficient.”
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