02
May
Unregulated Greenhouse Gas Emissions from Potent Pesticide Impact Climate Crisis and Public Health
(Beyond Pesticides, May 2, 2024) In the midst of a climate crisis and a lack of government recording of atmospheric measurements of sulfuryl fluoride (SO2F2), a study of the estimated emissions of sulfuryl fluoride throughout the U.S. shows elevated levels being released in California. The study, performed by researchers from Johns Hopkins University’s Department of Environmental Health and Engineering, University of California’s Scripps Institute of Oceanography, and National Oceanic and Atmospheric Administration’s (NOAA) Global Monitoring Laboratory, uses measurements from the NOAA Global Greenhouse Gas Reference Network and a geostatistical inverse model. Sulfuryl fluoride is a fluoride compound and pesticide used primarily for the extermination of drywood termites and beetles—linked to increased greenhouse gas emissions and having acute exposure consequences—with little data collected or reported on the amount of sulfuryl fluoride being used and released into the atmosphere. There is a long history of limited protections for the public centered around sulfuryl fluoride, with regulations from the U.S. Environmental Protection Agency (EPA) not addressing both dietary and nondietary exposure to fluoride compounds and the body burden this creates. With the dismissal of aggregate risk exposure, public health and safety and environmental sustainability are not prioritized. Organic alternatives have been left out of the conversation, but advocates are urging a shift in that direction.Â
The measurements utilized in the study are from across North America between 2015-2019 and were also compared to global emission rates, as has been done in previous studies related to this compound. The findings of this study show “California has the largest SO2F2 emissions among all U.S. states, with the highest emissions from southern coastal California,†conclusions consistent with prior analysis of the data. The study goes on to say that there were “zero to low emissions across most of the rest of the U.S,†which signifies California as an outlier. Â
In comparison to overall emissions, the authors found that “California emits 60-85% of U.S. SO2F2 emissions … equal to 5.5-12% of global SO2F2 emissions”. While analyzing this data, it was also found that when large spikes of emissions occurred, 98% of them were at sites in California. Total emission rates from California were found to be 0.26 Gg/year while the entire U.S. is 0.30 Gg/year, an alarming amount that calls for emissions in California to be regulated. Usage of sulfuryl fluoride in warmer states is expected since many of the targeted pests do not threaten areas with a colder climate. California, however, stands apart from other warm coastal regions that have low emissions. As a greenhouse gas (GHG), this is a concern since sulfuryl fluoride has a long atmospheric lifetime, high global warming potential, and strong infrared absorption properties.Â
After the Montreal Protocol was finalized in 1987, a shift away from methyl bromide, which is known as an ozone depleting substance, occurred and the ozone layer started to show signs of recovery. This shift, however, led to an alternative being used in its place–which is when global use of sulfuryl fluoride significantly increased. Both compounds, however, are still used under critical use exemptions from the Clean Air Act despite pushback. The 2014 Farm Bill also contains language that allows for EPA to disregard safety thresholds for fluoride compounds. In addition to structural fumigation, EPA began allowing sulfuryl fluoride in the production of raw foods in 2004 and processed foods in 2005. Multiple points of exposure to these compounds occur through drinking water, food, and in the air, which begs the question of why total exposure, including the effects of climate change, is not considered when accessing potent pesticides such as sulfuryl fluoride. When calculating aggregate risk under the Food Quality Protection Act, EPA is required to consider exposure to fluoride used for water treatment when evaluating the hazards of sulfuryl fluoride.Â
In 2008, a study determined that this pesticide was also a GHG after calculating its global warming potential. The Intergovernmental Panel on Climate Change officially recognized this and characterized sulfuryl fluoride as a GHG in 2013, and yet to date its atmospheric measurements are not recorded in the U.S., there is not a national inventory of its use, and EPA does not include it in any reporting programs. With global emissions of sulfuryl fluoride reaching a historic high, requirements for reporting and reducing these levels are needed, according to advocates.Â
The initial research on sulfuryl fluoride that led to it being approved in 1959 did not show that it was long-lasting in the atmosphere, nor did it show a high global warming potential. Since then, additional studies have shed light on sulfuryl fluoride as a GHG with detrimental effects. A study in 2009 found that this pesticide is as much as 4,000 times more effective at trapping heat than carbon dioxide. Despite this, legislation such as from the 2015 Paris Climate Agreement, Nations Framework Convention on Climate Change, or EPA have failed to include this potent pesticide.Â
Moreover, this study highlights other important consequences of sulfuryl fluoride use: “Apart from the climate-warming effect, there are public health and safety concerns surrounding the use of SO2F2 for fumigation. Most notably, there have been several documented cases of inadvertent human deaths caused by acute exposure.†Additional health effects include cancer, endocrine disruption, neurotoxicity, and impacts on reproduction and development. The authors also state that EPA considers sulfuryl fluoride as a “restricted-use pesticide (RUP) due to its inhalation toxicity†and yet does not require any reporting or regulate its usage.Â
In researching California’s utilization of sulfuryl fluoride, records from the California Department of Pesticide Regulation were reviewed. These records “indicate that ~85% of SO2F2 use (by mass) in California is for structural fumigation, while ~15% is for agricultural and commodity fumigation.†As a GHG, portions of sulfuryl fluoride that escape into the atmosphere after fumigation remain in the atmosphere for decades, contributing to the climate crisis. The authors of this study also reviewed aerial imagery over the Los Angeles Basin that shows plumes of sulfuryl fluoride emissions from fumigation sites within residential neighborhoods, a concerning fact since “aeration of fumigated structures has been demonstrated to occur rapidly, with over 90% of indoor SO2F2 lost to the atmosphere within the first 2 hours of ventilation.†California heavily relies on sulfuryl fluoride to combat the western drywood termite, which is difficult to eradicate since they establish colonies without having contact with the soil, do not forage for their food, and tend to make aerial colonies that are inaccessible. In addition, the fumigation of structures with sulfuryl fluoride helps to target current infestations but does not prevent further ones. This causes the need for reoccurring treatments and increased emissions.Â
California is the only state that currently keeps a public record of statewide application, even though this is not a requirement of EPA’s Greenhouse Gas Reporting Program or the National Greenhouse Gas Inventory. “The lack of inventory data on SO2F2 use complicates attempts to constrain U.S.-wide emissions,†this study states, which brings to light the inadequacies of EPA’s requirements around GHG. The authors go on to state that “under the Clean Air Act, the EPA is required to regulate emissions of hazardous air pollutants (HAPs), but SO2F2 has not been included in the list of HAPs to dateâ€. Despite multiple studies and petitions, the inaction of EPA and other agencies is apparent.Â
While many states have made goals around reducing GHG emissions, such as California has, this study raises a concern over the discrepancies affecting these goals: “California’s SO2F2 emissions provide a case study on how greenhouse gas emissions that are unaccounted for in emissions inventories can potentially offset progress made towards emissions reductionsâ€. The authors of this study call for action in stating: “The pervasive threat of termite infestations in warm-climate regions highlights the need for the development and practice of sustainable, entomology-guided techniques for controlling urban pest populations without the release of harmful atmospheric pollutants or climate-warming gases,†which aligns with Beyond Pesticides’ mission. Alternatives are available, and advocates are urging for these non-toxic options to be used in the place of potent pesticides. Non-chemical and mechanical controls, biological controls, and least-toxic chemicals have all been effective against drywood termites and can be used in place of sulfuryl fluoride.Â
For alternatives to other pests, Beyond Pesticides offers ManageSafe™ where you can search by pest type and see different options. There are also resources regarding products compatible with organic landscape management to help make a change and incorporate safer practices in homes and communities. Â
All unattributed positions and opinions in this piece are those of Beyond Pesticides. Â
Source:Â
Gaeta, D.C. et al. (2024) California dominates U.S. emissions of the pesticide and potent greenhouse gas sulfuryl fluoride, Communications Earth & Environment. Available at: https://www.nature.com/articles/s43247-024-01294-x Â
