As proposed in January 2011, HHS in April 2015 finalized a recommendation to change the current optimal fluoride range of 0.7 – 1.2 mg/L to an optimum value of 0.7 mg/L.
Unlike water quality standards developed by EPA under the Safe Drinking Water Act, the HHS recommendation on fluoride in drinking water is advisory and only becomes a regulatory requirement when adopted by state regulatory agencies.
Past practice by CDC has been to provide engineering guidance for state fluoridation programs, community water systems and schools operating water treatment systems. Current USCDC guidance provides for an operational range around an individual water system’s fluoridation target.
CDC in collaboration with American University’s Washington School of Law constructed a useful tool - FLUID - for locating state statutes, regulations and relevant case law related to fluoridation. Water systems seeking to adapt their current fluoridation practice can locate state fluoride points of contact through CDC’s My Water’s Fluoride webpage.
The 2006 National Research Council report on Fluoride in Drinking Water was prepared in response to an EPA request in 2003. At the time, the NRC report was widely expected to be basis for a review of the federal drinking water standards for fluoride in drinking water.
EPA indicated in 2010 that it was considering changing the health basis for the fluoride Maximum Contaminant Level from skeletal fluorosis to severe dental fluorosis. The agency at the time was conducting a dose-response assessment of the noncancer impacts of fluoride on severe dental fluorosis and the skeletal system.
EPA completed and made that assessment available for review in January 2011. It was the foundation for its joint action with HHS to review the fluoride standard. EPA summarized the analysis as follows: “The estimated oral RfD for fluoride, based on the endpoint of enamel pitting as manifest in severe dental fluorosis, is 0.08 mg F/kg/day for children during the period from 6 months to 14 years of age.”
This RfD will be used to re-evaluate the MCL Goal against which MCL options will be evaluated, where available fluoride occurrence data and treatment options underlie a cost-benefit analysis to support the agency decision.
EPA's next Six-Year Review of current drinking water regulations is scheduled for 2016. Evaluation of occurrence and treatment options begins with the Six-Year Review process, but a much more detailed analysis underlies an actual proposed rule.
One might wonder why a Federal Insecticide, Fungicide and Rodenticide Act tolerance for a pesticide used as a termite and agricultural insecticide fumigant is relevant to drinking water.
At present, this tolerance appears to be the focal point for federal policy coordination. Actions on related issues, including the fluoride MCL, are queued behind this discussion. In this instance, the risk management framework for sulfuryl fluoride stretches from reduction of ozone-depleting substances under the Montreal Protocol, to the nuances of FIFRA legislative text on what is “de minimus” risk, to drinking water exposure.
The United States is a signatory to the Montreal Protocol, agreeing to specific steps that lead to the phase-out of production and import of ozone-depleting substances, including methyl bromide. Sulfuryl fluoride is an alternative to methyl bromide, which is a widely used pesticide. This international treaty creates an obligation with limited exceptions for reducing the production and use of methyl bromide and thus increasing the necessity of maintaining a practical tolerance for sulfuryl fluoride.
EPA manages pesticide tolerances under FIFRA, which provides latitude for agency decisions based on de-minimus risk associated with pesticide exposure. As EPA seeks to regulate pesticide application of sulfuryl fluoride, the HHS recommends the addition of fluoride to drinking water for oral health, and fluoride is routinely added to consumer products for this benefit as well.
The public review elements of the sulfuryl fluoride tolerance review began in 2009, and the most recent comment period ended after being extended to July 5, 2012. EPA staff are now reviewing the latest round of comments.
Given the multiple offices within the agency and number of other federal departments involved, reaching a final decision will require engagement of senior EPA officials. No schedule is available for a final decision, and there are no public statements regarding how this rulemaking will impact the optimal fluoridation level, MCL for fluoride or the secondary MCL for fluoride.