(Beyond Pesticides, July 20, 2009) Public health and environmental advocates have asked the U.S. Environmental Protection Agency (EPA) to deny a request from Dow AgroSciences for a permit allowing it to release large amounts of sulfuryl fluoride, a toxic pesticide whose global warming effects are thousands of times stronger than carbon dioxide, onto farm fields in four states. Dow AgroSciences proposes using sulfuryl fluoride to sterilize soil in farm fields. The permit would allow the release of 32,435 pounds of sulfuryl fluoride on 65 acres of test plots in Florida, Georgia, Texas, and California. Yet, researchers have found that sulfuryl fluoride stays in the atmosphere at least 30-40 years and perhaps as long as 100 years and is about 4,000 times more efficient than carbon dioxide at trapping heat. Because of the aggregate effects of surfuryl fluoride, Beyond Pesticides jonined Fluroide Action Network and Envirornmental Working Group in petitioning the U.S. Environmental Protection Agency (EPA) to cancel the registration of the chemical due to dangerous levels in food and water.
“The hazards of using sulfuryl fluoride in agriculture have not been evaluated,” said Brian Hill, Ph.D., a staff scientist at the Pesticide Action Network. Releasing just 10 percent of the proposed amount into the air would be equivalent to releasing 15.5 million pounds of carbon dioxide. “A car that gets 30 miles per gallon would have to be driven 23 million miles — the distance of a trip circling the world over 930 times — to cause that much global warming,” said Dr. Hill.
“Other offices within EPA are currently working diligently to control climate change, which the EPA recognizes as the most pressing environmental challenge of our times,” said Justin Augustine of the Center for Biological Diversity. “It makes no sense for EPA’s Office of Pesticide Programs to work at cross purposes with the rest of the agency by allowing the use of such a harmful substance.”
Not only is sulfuryl fluoride a potent greenhouse gas, its high toxicity likewise poses significant human health and ecological risks. Thus far, EPA has not carefully reviewed the health risks for those exposed to the chemical or considered the impacts of the releases on endangered species and other wildlife. The groups’ letter asks EPA to take a hard look at these questions, including by consulting with the U.S. Fish and Wildlife Service.
“Dow would like to sell this toxic chemical to farmers across the country — and will apply to do so if this test goes well,” said Craig Segall of the Sierra Club. “We don’t need more global warming pollution, so we’re asking EPA to nip this problem in the bud.”
Sulfuryl fluoride has typically been used for structural pest control of termites. The insecticide is pumped into a tent that covers a termite-infested structure. When the tent is removed, the compound escapes into the atmosphere. Sulfuryl fluoride blocks a wavelength of heat that otherwise could easily escape the Earth, according to University of California at Irvine scientist. Carbon dioxide blocks a different wavelength, trapping heat near the surface.
“The only place where the planet is able to emit heat that escapes the atmosphere is in the region that sulfuryl fluoride blocks,” said Donald Blake, chemistry professor University of California at Irvine. “If we put something with this blocking effect in that area, then we’re in trouble ”” and we are putting something in there.”
According to Beyond Pesticide research, 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, 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. Since sulfuryl fluoride was only registered for use as a fumigant for existing infestations, EPA waived the environmental fate data requirements for reregistration in 1993 and did not consider ecological risks. The agency expects that non-target organisms would not likely be exposed to sulfuryl fluoride and that the pesticide would not leach to groundwater or persist in the environment for any significant amount of time.
According to the most recent data (2007) by the California Department of Pesticide Regulations, sulfuryl fluoride is the top pesticide used in the state for structural pest control and 14th for all pesticide application sites, with over 2.1 million pounds used in 2007 for structural pest control, over 3,200 pounds for landscape and rights-of-way applications, and about 42,000 on agricultural products such as almonds, broccoli, dried fruits, prunes, rice and other agricultural commodities.
Non- and least-toxic alternatives to using sulfuryl fluoride for structural pest management are viable and protect public health and the environment from hazardous chemical exposure. Ecologically-based land management systems and practices such as organic agriculture and organic lawns and landscapes also hold the key to freeing our country of its chemical dependency.