State releases findings of drywall investigation

Mar 23, 2009

South Florida Business Journal–March 23, 2009

by Paul Brinkmann

Chinese drywall samples give off sulfur gases and odor when exposed to extreme heat and moisture, according to a 60-page preliminary report released Monday by the Florida Department of Health.

The findings could explain why Florida’s hot, humid environment is an epicenter of the widening product liability crisis, said Dr. David Krause, state toxicologist, during a press conference Monday.

Drywall samples believed to have been manufactured in China showed a dramatic increase in sulfur gases when subjected to heat and humidity, while U.S.-made samples did not show as much of an increase, according to Krause.

Krause said the state’s new investigations confirm that sulfur fumes from defective drywall are causing metal corrosion in air conditioners and natural gas systems, which he said is cause for concern. He recommended homeowners worried about drywall problems contact their doctors, builders or maintenance professionals to evaluate any possible risks.

The new results do not help confirm or rule out health effects. The state is building a methodic scientific investigation that would take time, he said. Florida recently launched a new Web site focused on defective drywall problems.

Lab tests were performed by Unified Engineering, a private lab.

The lab tested one sample made in the U.S. by National Gypsum Co.’s GridMarx brand and three samples believed to have come from China, according to a letter that accompanied the results. However, only one of the three samples believed to be Chinese was marked as such.

“There is a distinct difference in drywall that was manufactured in the United States and those that were manufactured in China,” said Lori Streit, a principal scientist with Unified, in a letter. “The Chinese samples contained traces of strontium sulfide inclusions and more organic material that the GridMarx sample (United States). However, it is not yet known if either contributed to the odor.”

“It is clear that exposure to moisture accelerates the release of volatiles from the drywall,” Streit wrote. “Both the outer paper and the gypsum from the drywall had noticeable odors after moisture exposure and were found to release sulfur compounds.”

Krause said the test results of Chinese drywall showed only materials that would be associated with natural gypsum from gypsum rock mines.

“The presence of quartz and anhydite contradicts rumors that Chinese drywall was made from fly ash or from flue-gas-derived [synthetic] gypsum,” Krause said. Anhydite is a mineral frequently found in evaporite deposits with gypsum.

The Florida Department of Health is tracking 150 complaints about drywall causing metal corrosion in and odors in homes. The U.S. Consumer Product Safety Commission also is investigating the extent of the drywall problem.

Homeowners have filed lawsuits in recent months, claiming that the drywall has caused them to suffer health problems. It is also alleged to have cause corrosion of copper tubing used in air conditioners.