For many years the phosphate fertilizer industry was releasing two incredibly hazardous wastes into the enviornment: Hydrogen Fluoride and Silicon Tetrafluoride. These highly reactive chemicals were causing harm to people, live stock, and vegetation near the factories. They were eventually required, by government to capture these gasses.
The solution was to use wet scrubbers to catch these chemicals. (Basically they force the emissions of the plant through a water vapor, thereby trapping the hazardous waste). The two chemicals combine to make Hydrofluorosilicic acid. This fluid, unpurified, is loaded directly into trucks and sold to cities and municipalities across the country, including Burlington.