(Beyond Pesticides, May 14, 2012) The U.S. Environmental Protection Agency (EPA) is accepting public comment on several complex regulatory issues related to the agency’s commitment to phase out the toxic fumigant sulfuryl fluoride. At one time EPA had supported sulfuryl fluoride as a replacement for a second fumigant, methyl bromide, which the United States is obligated under international treaty to eliminate due to its contribution to ozone depletion. However, EPA reversed that support once further research and a refined risk assessment established that aggregate exposure to sulfuryl fluoride does not adequately protect the health of certain population subgroups. Although EPA decided unequivocally in 2011 to phase out all food-related uses for sulfuryl fluoride, the current public comment opportunity revisits key elements of that decision and could open the door for an unwarranted and unnecessary extension of this toxic fumigant’s allowance.
Initially registered in 1959 to kill termites and other wood-boring pests, sulfuryl fluoride gained attention as a potential alternative to methyl bromide as a broad spectrum insect fumigant in post-harvest commodity storage and food processing facilities. The need for such alternatives became more pressing as the U.S., a signatory of the Montreal Protocol, gradually reduced the amount of methyl bromide allowed for such purposes with an eventual goal of eliminating all such uses. EPA first allowed sulfuryl fluoride as a direct fumigant on various grains and dried fruits in 2004. Beyond Pesticides, in collaboration with the Fluoride Action Network (FAN), filed formal objections to those allowances as well as additional uses authorized by EPA the following year. In 2006, Beyond Pesticides and FAN joined by the Environmental Working Group (EWG) petitioned EPA to revoke all previously approved food-related used for sulfuryl fluoride. In the petition, the groups cited the findings of a major National Research Council report published that year, which concluded that the aggregate exposure to fluoride represented an unacceptable risk for certain susceptible subgroups.
The 2006 petition laid the foundation for EPA’s reassessment of aggregate exposure risk and led to its decision in 2011 to phase out all food-related uses for sulfuryl fluoride over a three year period. In that decision, the agency extended the three year allowance only to economically significant commodities, including walnuts, cocoa, and dried fruits other than raisins, for which there are no readily-available alternative treatments. However, EPA is using the current public comment opportunity specifically to invite comment on three legal issues which are critical for defending its 2011 phase out decision. EPA further states that it is soliciting this additional comment in response to the positions advanced by proponents of continued allowances for sulfuryl fluoride who have argued that EPA acted improperly when ordering the phase out. Significant revisions to EPA’s interpretations of these underlying legal issues in response to public comment could be used to justify a reversal or delay in its commitment to a phase out.
Specifically, EPA is inviting comment on whether the exposure reductions that would result from prohibiting sulfuryl fluoride as a fumigant are so small that they can be legitimately disregarded. Proponents for continuing sulfuryl fluoride’s fumigant-related uses argue that human exposure through food is negligible compared to other vectors, such as water that is either naturally fluoridated or to which fluoride is intentionally added, and can therefore be dismissed. Additionally, EPA is asking whether the food-related exposures to sulfuryl fluoride should be considered along with non-pesticidal exposures in the cumulative risk assessment and how other statutory obligations (in this case, the requirement to phase out methyl bromide, which was incorporated into the Clean Air Act) can be weighed alongside the criteria regulating pesticides. Citing the overarching importance of the Clean Air Act obligations, the Natural Resources Defense Council submitted a letter to EPA in 2011 opposing the disallowance of any sulfuryl fluoride uses that would lead to prolonged or increased methyl bromide use.
Beyond Pesticides has never considered sulfuryl fluoride necessary for the safe storage and handling of our food supply and does not support an extension of the currently mandated phase out. There are many viable alternatives to sulfuryl fluoride and methyl bromide fumigation, including temperature manipulation (heating and cooling), atmospheric controls (low oxygen and fumigation with carbon dioxide), biological controls (pheromones, viruses and nematodes), and less toxic chemical controls (diatomaceous earth). Neither fumigant is permitted in organic food production and handling. Beyond Pesticides, FAN, and EWG all agree that EPA should also reduce aggregate fluoride exposure by reducing or eliminating fluoride in drinking water. The NRDC letter points out that municipal drinking water is by far the greatest route of fluoride exposure. However, the Food Quality Protection Act (FQPA), which amends the Federal Insecticide, Fungicide and Rodenticide Act (FIFRA) and the Federal Food Drug and Cosmetic Act, requires EPA to limit overall aggregate risk from food and non-food use pesticide exposure to the agency’s allowed level, which is reached through exposure to fluoridated water alone. This calculation is not determined through a relative risk assessment, so the argument that the food use exposure is minimal compared with water exposure does not meet the statutory aggregate risk standard in FQPA. Because this has been characterized as a “health-based standard,” the agency is not permitted to ignore or dismiss an elevated risk because of a pesticide benefit claim. So, it cannot be an issue in this case. However, in the general case when aggregate risk is not as high as it is with sulfuryl fluoride, the agency typically ignores the availability of organic production methods that do not rely on the toxic pesticide under review, and assumes a benefit that is not justified because of available less toxic methods.
Sulfuryl fluoride is a hazardous chemical which has been linked to cancer as well as neurological, developmental, and reproductive damages. Sulfuryl fluoride is acutely moderately toxic by oral exposure (Toxicity Category II) and slightly toxic for acute inhalation (Toxicity Categories III and IV) and dermal vapor toxicity (Toxicity Category IV). Residents and workers are at risk for neurotoxic effects from acute exposure. Subchronic studies on rats have indicated effects on the nervous system, lungs, and brain. Developmental and reproductive effects have also been noted in relevant studies on rats. According to the National Research Council (NRC), fluorides might also increase the risk of developing Alzheimer’s disease, and boys exposed to fluoride in drinking water are five times more likely to develop osteosarcoma, a rare form of bone cancer. Further studies conducted since the publication of the NRC report have confirmed the dangerous effects associated with fluoride exposure. Additionally, fluoride has been placed by EPA on a list of “Chemicals with Substantial Evidence of Developmental Neurotoxicity.” Two dozen separate studies have linked fluoride exposure with a reduction in children’s IQ levels.
All unattributed positions and opinions in this piece are those of Beyond Pesticides.