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An environmental group has called on product specifiers to seek out recycled drywall and new product made from natural gypsum rather than
material produced as a byproduct of burning coal. But gypsum industry officials say this could be a tough request to fulfill. Opting for lightweight drywall might be the best possible compromise.
The Healthy Building Network made its recommendation because it seeks to limit releases of mercury into the air when companies
manufacture drywall out of material produced in coal plants’ flue-gas desulfurization (FGD) process.
“Once the FGD residue is taken from the coal plant to the drywall manufacturing plant, it is mixed with water and other ingredients to make up
the core of a drywall board and heated in an oven to drive off the water and bake the ingredients into a homogenous board,” an HBN alert says.
“During this heating process, some of the mercury pollution that was captured in the flue of the power plant is released from the smokestacks of drywall factories.”
Between 2009 and 2018, America’s drywall plants released more than 3 tons of mercury into the air, HBN says. Mercury gets released when both
FGD and natural gypsum are created, but the amounts are higher when FGD is used. “Because mercury is persistent in the environment and bioaccumulative (it magnifies in the food chain), it doesn’t disappear, but instead becomes a global pollutant impacting people and the environment all over the world,” HBN says.
HBN suggests product specifiers avoid FGD gypsum whenever possible. Alternatively, they should specify drywall made out of post-consumer
recycled content, such as new drywall made out of old drywall that had been sold to dealers and contractors but never installed or at least not painted.
But Stephen Meima, executive director of the Gypsum Association, says drywall manufacturers don’t differentiate between FGD and natural gypsum because both meet the same standards. “We don’t believe there is any difference betwixt the two,” he says. A 2014 study by the Environmental Protection Agency did find more mercury emanating from the production of FGD than of mined gypsum, but nevertheless supported using FGD gypsum in wallboard, saying the likely presence of mercury in installed drywall was many times below federal benchmark levels of concern.
As for new drywall made from old, Meima says the effort to recycle board scraps “has been something that everyone has been trying,
including our members. But there are challenges. The clean cuttings off a job site or dunnage within a plant is recyclable. If a manufacturers’ plant is set up, they’ll take it back because they know the chemical constituents. That’s the low-hanging fruit and has been so. The holy grail is the recycling of panels that have been in place. But with that comes the risk and liability of contaminants where the board has been installed.”
If neither is available, then turn to lightweight drywall because it contains less material per square foot, HBN says.