One of the most important points is the fact that the fluoride destined for water treatement is an inconsequential portion of the mined fluoride. The mining companies incur no special cost in the normal disposal and avoid no costs whatsoever from water additive sales. Because the process requires energy and reagent inputs it saves no money. Recently almost all of the sodium fluoride comes from overseas sources because the phosphate rock based manufacture is too expensie to be price competitive.
At the 2014 National Oral Health Conference, CDC Fluoridation Engineer, Kip Duchon described some additional important manufacturing details. HFSA is accumulated at the phosphate rock processing plant in 20,000 gallon containers. When the container is full it is analyzedfor contaminants. If it passes the grade the entire container is used for both pharmaceutical and water additive grades without further processing.
—-Source: Kip Duchon, National Fluoridation Water Engineer, 2013 National Oral Health Conference presentation.
And the likely all understand that NSF-60 standard for water additives is more specific and demanding than is the USP standard for medication. The USP also does not provide for independent quality control oversight. The manufacturer is the only guarantor of USP purity.
That the water additive grade HFSA is of poor quality or that the pharmaceutical grade is better is just one of the many invalid arguments which sadly threaten America’s better oral health.