Safe Drinking Water Exemptions for Carbon Dioxide Class VI Wells Threaten Rural Water Supplies
by Carolyn Raffensperger and Dr. Ted Schettler on behalf of the Stop Carbon Capture Alliance
Background
The carbon capture industry is pushing to weaken protections under the Safe Drinking Water Act (SDWA) to expand areas where they can site Class VI injection wells for carbon dioxide (CO2). Documented failures at injection wells in Illinois and Texas have shown that carbon capture injection wells need more stringent protections for drinking water, not less.
Disproportionate Impacts on Rural Communities
The industry wants to create exemptions to Federal rules under the SDWA that protect potential sources of drinking water, including water supplies that are not currently used for drinking water, provided an aquifer has enough water to supply a public system and contains less than 10,000 mg/L of total dissolved solids. Weakening these standards would discriminate against small rural communities where people rely on well water for drinking, as well as ranchers and farmers who use underground aquifers for irrigation and livestock watering operations.
If a CO2 injection well were to leak into an aquifer used for well water, irrigation, or livestock, it would acidify the water—mobilizing heavy metals and potentially other toxic materials—rendering it unusable in agriculture, for livestock, or for any drinking water purposes now or in the future. Weakening protections under the SDWA is even more concerning when we consider droughts and water scarcity could necessitate using these aquifers for drinking water sources, as crises mount and treatment technology improves.
Snowy River Project Shows Protections Matter
Exempting certain aquifers from review when EPA considers Class VI well permits would clearly have a significant impact on injection wells the industry is proposing across the country. The Snowy River Carbon Sequestration Project proposed by ExxonMobil (via Denbury Carbon Solutions) shows how weakening the SDWA could impact real-world protections for communities.
The Snowy River project proposed injecting 150 million tons of CO₂ underground over 20 years, sourced from natural gas processing plants in Wyoming and injected into up to 15 wells in southeastern Montana’s Carter County. The Bureau of Land Management (BLM) originally determined the project would have no significant impact, prompting landowners, farmers, and ranchers to raise concerns about the risks posed to groundwater used for watering livestock and crops. Facing heavy scrutiny ranging from agricultural disruption and groundwater threats to pipeline safety, the BLM narrowed the entire project footprint, authorizing only a single stratigraphic test well on state land to collect geologic and hydrologic data.
Exxon later withdrew its application for the project. While they have not stated the reason for abandoning the project publicly, this project underscores the risks of moving forward with a project of this scale without a deeper understanding of impacts on groundwater resources. Removing aquifers from federal protections could narrow analysis for future projects before the public understands the impacts. If the industry has its way, many aquifers across the county could lose protections under the SDWA and would move forward without analysis on impacts for many underground sources of water.
We Need Stronger, NOT Weaker, Protections
Weakening the SDWA would shift more risks from injection wells onto rural communities, farmers, ranchers, and future generations. To protect drinking water supplies and underground aquifers, we need to halt CO2 injection wells until we close regulatory gaps and increase oversight of injection wells, a demand coming from groups around the country.
This fact sheet can also be found on Carbon Capture and Storage (CCS) Facts, a website sponsored by SEHN on behalf of a large number of individuals, local grassroots and community groups, and larger organizations working to advance public policies based on science and justice. The Stop Carbon Capture Alliance brings together communities across the country fighting dangerous CO2 pipelines, opposing efforts to fast-track permitting for inherently unsafe injection wells, and stopping the flow of billions in public subsidies driving this industry forward.