The nasty wallboard emitting H2S (hydrogen sulphide, a gas) is apparently spread around North America. The Canadians are now complaining about it. I blogged about this latest Chinese import to raise health questions. The stuff was apparently imported from 2001 to 2007. One estimate: 929,000 square metres were imported through Vancouver alone during that period. That's a lot of walls. Home Depot quickly announced it has never sold Chinese-made drywall. In Florida one lawsuit names German drywall maker Knauf Gips KG which has Chinese plasterboard factories.
One Canadian news report suggests the questionable wallboard contains gypsum that was previously used to remove sulphides from coal. And then cleverly recycled. Another suggestion, based on testing of the wallboard in Florida: it contains coal ash because there are significant amounts of organic material as well as sulphides.
Gypsum is used in wallboard globally. It's a naturally-occuring, very soft mineral composed of calcium sulfate dihydrate, CaSO4·2H2O. Note there's a sulphur ion there. Any impurities that cause the gypsum to decompose....
The U.S. has enormous gypsum deposits and it is found in numerous sedimentary rock layers across the globe though China is not a major producer so companies might be anxious to find ways to dilute the supply. Gypsum also breaks down over time in water. What's it look like? Ever see White Sands, New Mexico? Those are drifting dunes of gypsum.
Here's America's Watchdog complaint center. Who's investigating? Florida Health Department. The federal Consumer Product Safety Commission, also. Currently there are no standards for what can be put into imported wallboard so I wouldn't be buying any made around Chernobyl either.
And if the stuff causing wallboard worries turns out to be coal ash, our old friend from the Tennessee trauma, it's only the tip of the slurry of coal ash angst. We're using it all over the place, apparently with no thought of what it can do to the ground water. Or our health.