Scripps Howard News Service


By Isaac Wolf
Scripps Howard News Service

Wednesday, November 4, 2009

Samples of Chinese drywall have been found to contain significantly more sulfur-generating bacteria than comparable North American drywall, a finding scientists believe could provide a pathway to help desperate and furious homeowners.

While federal officials and industry experts say that there is no silver bullet for cleaning tainted drywall — and they’re skeptical of any company that promises a quick fix — there is increasing interest in exploring whether Chinese drywall’s high bacteria count may be generating chemicals that make people sick and blacken appliances.

“We think we’ve isolated a bacteria,” said D. Douglas Hoffman, CEO of the National Organization of Remediators and Mold Inspectors, an Abita Springs, La. organization that focuses on indoor air quality and mold problems.

The bacteria is believed to be consuming the main ingredient of drywall and releasing hydrogen sulfide, which has a nauseating rotten egg smell.

Hoffman’s group is studying bacteria in drywall in two research labs, and, though he is not ready to announce definitively that bacteria may is the culprit for high quantities of sulfur, he thinks the research is promising: It could mean that affected houses could be cleansed by bacteria-killing disinfectants.

The financial stakes are growing. The U.S. House of Representatives last week approved legislation to help pay to repair tainted drywall, scores of lawsuits are piling up and homebuilders are setting aside millions of dollars for fixes. Chinese drywall is believed to have been used in 60,000 to 100,000 houses built in 2006 and 2007.

Led by the U.S. Consumer Product Safety Commission, federal authorities are trying to pinpoint why almost 2,000 homeowners — many in Florida — have complained that drywall has made them sick or blackened their appliances. The federal investigation is expected to release its findings by Thanksgiving, and an interim report last week found that samples of Chinese drywall released 24 times as much sulfur as North American drywall.

The reason tainted Chinese drywall is releasing so much sulfur gas may be because it’s loaded with a sulfide-producing bacteria, says Mike Shaw, executive vice president of Interscan Corp., a Chatsworth, Calif. company that makes toxic gas detection equipment. Lab tests have shown Chinese drywall samples to contain up to 10,000 times as much sulfur-producing bacteria as North American samples, Shaw said in an interview at Interscan’s suburban Washington D.C. office.

The elevated bacteria levels could be the result of contaminated water or paper, he added.

Federal authorities have expanded their investigation to include research on bacteria, said Scott Wolfson, director of public affairs for the CPSC. In an interview, he cautioned against rushing to premature scientific judgments.

“The science should drive the solution of how to help these families, many of whom have been displaced or are suffering health effects while in their home,” Wolfson said. “We are conducting the most expansive investigation possible, so that we provide the right answers and solutions to these affected homeowners, as quickly as possible.”

If bacteria are generating the sulfur—and the elevated sulfur levels are the cause of respiratory problems, bloody noses and corroded metal appliances—then the solution could be based in fumigation, Shaw said. A heavy-duty disinfectant, chlorine dioxide, could be used to fumigate houses and kill the bacteria. But Wolfson and other experts cautioned that the bacteria could easily move from one piece of drywall to another.

Hoffman, of the industry group, said that an effective toxic drywall cleanup would require not just one round of fumigation but also follow-up checks, because some bacteria might evade the initial effort.

He said that while his group is developing a protocol for neutralizing homes with toxic drywall, “I don’t think there’s any one silver bullet.”