‘Volatile sulfur compounds’ in Chinese drywall

MANATEE — Limited laboratory testing of Chinese-made drywall found it contained higher levels of sulfuric and organic compounds than an American sample, a consultant said in a preliminary report released Friday.

But more testing is needed to determine whether that is responsible for foul odors and corroded metal as reported by hundreds of Florida homeowners, including several in Manatee, Unified Engineering Inc. said in a report submitted to the Florida Department of Health.

The health agency had hired the Illinois laboratory to test four drywall samples as part of its investigation into the tainted drywall issue, which first surfaced locally last year.

“In summary, the odor that has been described by investigators and homeowners in Florida residences originated from the emission of volatile sulfur compounds,” the lab report said. “There is a distinct difference in drywall that was manufactured in the United States and those that were manufactured in China.”

The three Chinese samples — including one made by Knauf, the company at the center of the controversy — all contained traces of strontium sulfide while the American sample did not, the lab said.

Strontium sulfide is a gray powder that emits a hydrogen sulfide, or “rotten eggs,” odor when exposed to moist air, according to a National Oceanographic and Atmospheric Administration chemical database.

The Chinese samples also contained three other sulfuric compounds:

n Hydrogen sulfide, called highly flammable and toxic by the NOAA.

n Carbonyl sulfide, which the NOAA database calls highly flammable and potentially fatal if ingested or absorbed through the skin.

n Carbon disulfide, described by NOAA as an extremely flammable liquid that can emit highly toxic fumes.

The American sample also contained those compounds, but it couldn’t be determined if it was contaminated by the other samples as all had been shipped together, the lab said.

The Chinese drywall also contained at least 5 percent organic material, higher than the American drywall, the lab said.

“It is not yet known if either contributed to the odor,” the lab report said of the sulfuric and organic material. “The Chinese samples give off a sulfur odor when exposed to extreme heat and moisture. It is clear that exposure to moisture accelerates the release of volatiles from the drywall.”

The lab said it could not tell whether the sulfuric compounds came from the gypsum used to make the drywall, the paper coating on the drywall, the adhesive used to attach the coating to the drywall or from insecticide or fungicide applied to the drywall when it entered the United States. The lab recommended further testing.

State health officials are reviewing the report and were unavailable for comment until a media briefing scheduled for Monday, said Susan Smith, an agency spokeswoman.

The state has received more than 150 drywall-related complaints from 19 counties, including 27 from Manatee, she said. The agency also has set up a Web site — www.doh.state.fl.us/ environment/community/indoor -air/drywall.html — devoted to the issue.