As hundreds of Floridians are complaining of putrid odors, corroded metal and respiratory/nasal problems in their recently built homes, theories are multiplying as to what’s happening and why.
And it’s not, they theorize, solely Chinese drywall’s fault.
Some say the culprit could be a sulfur-based fungicide that was applied to the drywall to prevent mold while it was shipped overseas. Others argue the gypsum used in the drywall contained higher-than-normal levels of sulfur, or were tainted with waste fly ash or decomposing bacteria. Yet others think the Chinese gypsum mines were contaminated by runoff from nearby farms.
Dewell Crews is among those who think they may have discovered the reason.
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Crews, a Bradenton man who has worked in the building and lumber supply industry for six years, thinks a 2004 change in chemical preservatives used in pressure-treated wood could be a culprit. The new preservative is much more corrosive to metal, and somehow could be interacting with Chinese drywall to emit sulfuric gases, he said.
“I’m not sure if that’s the case, but at least it’s something we should be looking at,” Crews said.
Others discount his theory and advocate their own. But none has conclusively answered a question that continues to vex a growing army of researchers, health officials and scientists:
What’s the cause?
Finding that answer is a complex process full of twists and turns that could take months or even years, say those looking at the issue.
“It’s like an onion: Every time you peel a layer, you find something else,” said Mike Foreman, of Foreman & Associates, a Sarasota construction consulting firm that has been working on the issue almost from the beginning.
Many studying drywall
This much is known: Something’s going on with certain brands of Chinese drywall, and it’s becoming more widespread.
What began with a few Florida homeowners’ complaints of “rotten eggs” odors, blackened metal and allergic reactions has mushroomed into an international political and media issue, sparked a flurry of lawsuits, prompted investigations from various state and federal agencies and created cottage industries.
Now, nearly 450 Florida homeowners have filed complaints with state health officials. The U.S. Consumer Product Safety Commission has received more than 460 reports from 19 states and the District of Columbia. The issue likely will be discussed when President Barack Obama travels to China later this year. Drywall-related lawsuits have been filed in at least eight states. And Congress is considering two drywall-related bills.
Amid that backdrop, several government agencies — the product-safety board, the U.S. Environmental Protection Agency and the Florida Department of Health, among them — are collaborating to investigate the issue. They’re looking at how the drywall was made, what’s in it and what health risks, if any, it could have for humans.
Joining them are scientists, environmental consultants, forensic experts and others, each conducting their own investigations.
Many differing theories
Each theory has generated a wide range of differing opinions.
Foreman, for example, doubts Crews’ theory because very little pressure-treated wood is used in Southwest Florida home construction. And Gary Rosen, a Davie environmental/construction consultant who also is investigating the drywall issue, agrees with Foreman.
“In South Florida it’s all metal framing, not wood,” he said. “The cause is not the wood framing. That one you can rule out.”
Rosen said fungicide is a more plausible explanation, saying no mold has grown on a piece of Chinese drywall that he’s left outdoors for more than a month.
“They either sprayed a ton of it (fungicide) or sprayed a highly concentrated form of it,” he said.
Another inconclusive theory is that there’s something in the adhesive used to bind the outer paper to the drywall.
Answer within drywall?
Still, the prevailing opinion within the scientific community is that the source is within the drywall itself — but there’s disagreement on what it is and where it came from.
The Alliance for American Manufacturing, citing research by a Fort Myers environmental consulting firm, says Chinese drywall manufacturers recycled gypsum previously used to filter smokestacks in coal-burning power plants. Chinese coal contains high levels of sulfur, which was absorbed by the gypsum later used in drywall, the group contends.
“When this drywall meets humidity, it emits sulfur dioxide, carbon disulfide and other ‘ides’ too numerous to mention,” said Kerri Houston Toloczko, a senior analyst for the nonprofit manufacturing group. “These particulates are acidic in nature and immediately start rotting everything in their path as well as making people ill.”
But others note laboratory testing has found no evidence of that and point to what has been found in Chinese drywall samples: high levels of sulfur, strontium (a naturally occurring metal) and organic material.
Mixing strontium and sulfur results in strontium sulfide, a corrosive gas that a Gainesville forensic construction expert believes is the primary culprit.
“The physical evidence is overwhelming,” said Scott “Spiderman” Mulholland, of U.S. Building and Consultants Inc.
But Foreman wonders whether chlorine, which also has been found in Chinese drywall, is playing a role.
“For chlorine to be in there, it’s highly unusual,” he said. “I don’t think the strontium is the main culprit. It’s probably a combination of things.”
And no one has conclusively determined yet what the organic contamination is and what role, if any, it’s playing.
Some say it is bacteria that is interacting with iron and sulfur compounds to produce sulfuric odors, but others say there likely is not enough bacteria to cause an odor.
Rosen theorizes that it is excrement that invertebrates left behind millions of years ago, becoming embedded in the gypsum ore now being mined. “This is crab poop,” he said.
Others suspect that the organic compounds came from farms surrounding the Chinese open-pit gypsum mines. Skeptics question whether that’s possible, as gypsum is found underground.
The various governmental agencies investigating Chinese drywall have declined to speculate on a potential cause, saying the answer can only be found through meticulous scientific testing.
As a result, many plan to continue their own search for the answer — and debate what that answer might be.
“It could be any number of things at this point,” Rosen said. “That’s what makes it so fun and interesting.”
Duane Marsteller, Herald reporter, can be reached at 745-7080, ext. 2630.