Reduced water and energy consumption, landfill avoidance, and preservation of natural resources are just some of the advantages flue gas desulfurization (FGD) gypsum offers when used to manufacture gypsum panels. For more than 20 years, Gypsum Association members have successfully and safely developed and deployed technologies to use flue FGD gypsum as a primary ingredient in the manufacture of gypsum panels. The gypsum industry purchases FGD gypsum from electric utilities who employ a washing and purification process to make FGD materials into an FGD gypsum product. Natural gypsum and FGD gypsum have the same chemical composition; they are each calcium sulfate dihydrate (CaSO4·2H2O). Today, almost half of all gypsum used in the manufacture of gypsum board in the United States is FGD gypsum, also known as synthetic gypsum.
The Gypsum Association does not express a preference for FGD or natural gypsum. Those who are most concerned about global warming potential, energy conservation, water conservation and landfill avoidance, and preservation of natural resources may consider synthetic gypsum an environmentally preferable product because its life-cycle impacts are lower in those areas than natural gypsum. Also, EPA considers FGD gypsum as an important aspect of the Agency’s Sustainable Materials Management program, which it describes as “a systemic approach to using and reusing materials more productively over their entire life cycles.”
Importantly, studies have universally shown washed FGD to be safe. Risk evaluation information released by EPA regarding FGD affirms the safety of gypsum board manufactured with washed FGD gypsum. Specifically, in its February 2014 final report Coal Combustion Residual Beneficial Use Evaluation: Fly Ash Concrete and FGD Gypsum Wallboard, EPA states, “Based on the analysis set forth in this document, the evaluation concludes that environmental releases of constituents of potential concern (COPCs) from CCR fly ash concrete and FGD gypsum wallboard during use by the consumer are comparable to or lower than those from analogous non-CCR products, or are at or below relevant regulatory and health-based benchmarks for human and ecological receptors.” EPA’s evaluation further states, “The beneficial use of CCRs, when conducted in an environmentally sound manner, can contribute significant environmental and economic benefits. Environmental benefits include reduced greenhouse gas emissions, reduced need for disposing of CCRs in landfills, and reduced use of virgin resources.”
EPA’s review corroborates the safety of FGD gypsum and encourages its continued use. The report’s conclusion states “EPA supports the beneficial use of . . . FGD gypsum in wallboard. The Agency believes these beneficial uses provide significant opportunities to advance Sustainable Materials Management (SMM).” Read the report.
In March 2023, EPA and the U.S. Department of Agriculture’s Agricultural Research Service completed their Beneficial Use Evaluation: Flue Gas Desulfurization Gypsum as an Agricultural Amendment. EPA applied a specific analytical framework the culmination of which was “a national-scale probabilistic model of potential environmental fate and transport. No concerns were identified for the vast majority of modeled application scenarios. Some limited potential for risk was identified from release of selenium to surface water when FGD gypsum is applied on across every available field at the highest rates and frequencies. Yet even in this extreme and unlikely scenario, identified risks can be mitigated through minor limits on application practices. Based on these results, the beneficial use of FGD gypsum can provide meaningful benefits to agricultural fields while remaining protective of human health and the environment.” The Beneficial Use Evaluation can be found here.