Photo: Shortnose sturgeon in the Connecticut River, CT. Copyright: Robert S. Michelson/Photography by Michelson, Inc. Collected from NOAA Fisheries Directory.

Introduction

In August of 2025, the gas and electric utility company Eversource filed a scoping notice to build a new 6,700 hundred feet segment of methane gas pipeline under the Connecticut River. The pipeline would potentially impact state parks in the towns of Middletown, East Hampton, and Higganum. This project expands the capacity of fossil fuels while also causing significant threat to the local ecosystems and communities. 

The so-called “Southeast Resiliency Project” is a new pipeline that stretches roughly 34.5 miles from Middletown to Montville, CT. The vast majority of the project is built, leaving this section, crossing under the Connecticut River, remaining. The pipeline is being constructed alongside existing electrical easements owned by the company. After significant public pressure, the project is currently undergoing an Environmental Impact Evaluation by the Department of Energy and Environmental Protection (DEEP). 

Eversource proposes to build the pipeline under the Connecticut River using the process of Horizontal Directional Drilling (HDD). HDD entails drilling a curved horizontal hole under the earth and pumping drilling fluid or mud inside to form a hole for a pipe segment to go through. The exact chemical components of Eversource's drilling fluid are unknown to the public, but may be damaging to marine organisms and water quality.  While less risky than traditional trenching methods, HDD has the risk of unintentional release of drilling fluids into the water. Drilling fluid may release toxins into the Connecticut river which can flow downstream. This high-density fluid can also coat the riverbed and block photosynthesis of fragile ecosystems (Reid, Sierra Club).

Methane and Its Consequences

Methane-based fuel is described as “natural gas,” an ironic and misleading title, given that it is mostly composed of methane, a greenhouse gas which is produced through a process called hydraulic fracturing or “fracking.” Methane is an extremely potent greenhouse gas which traps heat in the atmosphere at a rate 80 times more powerful  than carbon dioxide over the span of 20 years (Rocky Mountain Institute 2023).  4.8% of all methane in pipeline systems leaks and goes unburned between the process of fracking and its eventual use in homes and buildings, directly contributing to climate change (Robert Howarth, EPA Data 2022). Furthermore, burning methane emits fine particulate matter (PM2.5), which can cause significant respiratory and cardiovascular impacts. Despite its significant health and environmental harms, methane gas use continues to rise at alarming rates  across the country and world along with the expansion of the fossil fuel industry (National Oceanic and Atmospheric Administration).

Pipelines in the Northeast

About 60%  of energy generated in Connecticut is supplied by natural gas (U.S. Energy Information Administration). There are three major interstate natural gas pipelines that run through the state of Connecticut: the Enbridge owned Algonquin, TC Energy owned Iroquois, and Kinder Morgan owned Tennessee. It is not uncommon for major industries to appropriate the names of indigenous communities for their pipelines. Since the early 2000s when major advancements were made in hydraulic fracking and horizontal directional drilling, methane has been much cheaper to obtain and therefore has been increasingly relied upon. With 591 miles of intrastate pipelines per 330 million people in the state, Connecticut has among the highest number of gas pipelines per capita in the Northeast U.S. 

Pipeline Expansion and Local Environmental Justice

The census block adjacent to the pipeline located in Middletown, CT, is designated an Environmental Justice Community and Environmental Justice Distressed Group by the state of Connecticut (DEEP State Policy). This portion of Middletown is a region where almost exactly 50% of community members are low income. Not only are wealthy communities less likely to have pipelines constructed within or near them, but also census tracts with higher proportions of Black residents are significantly more likely to be associated with proposed pipeline projects (Davis et al. 2025). 

Pipeline placement is also often related to an area's level of educational attainment. Researchers found that pipelines are more likely to be built in places where people have lower levels of educational attainment (Davis et al. 2025). Moreover, protests against the construction of pipelines are affected by a community's socioeconomic status. The placement of future pipelines will likely be influenced by local voices, meaning that unequal distribution of pipeline locations could potentially worsen for some marginalized communities, who typically have lower bargaining power (Davis et al. 2025). 

Endangered Species of the Connecticut Rivershed May be Impacted

Several endangered species that populate the Connecticut River may be affected by pipeline construction and contamination. These include two species of highly vulnerable sturgeons and mussels. The last remaining spawning population of the federally-endangered Shortnose Sturgeon resides in this portion of the Connecticut River. Furthermore, there is recent evidence that populations of another federally endangered species, the Atlantic Sturgeon, may be recovering in the Connecticut River (DEEP, “Migratory Fish Runs of Connecticut”). These already vulnerable species are at risk from pollution caused by pipeline construction or leaks which cut through their essential migration routes.

The pipeline construction may be especially dangerous for mussels which remain attached to growing surfaces, including the river bottom, for most of their lifecycle. The dwarf wedgemussel only lives in a few places across the Connecticut River and its tributaries, but in the past, it populated much of the Connecticut and Quinnipiac Rivers (CT DEEP “Dwarf Wedgemussel”). It is considered federally endangered, with population sizes decreasing dramatically in the past century (CT DEEP “Dwarf Wedgemussel”). The yellow lampmussel was rediscovered in the Connecticut River in 2006 and is also considered endangered in states across New England (CT DEEP “Yellow Lampmussel”).

Photo: Dwarf Wedgemussel by Michael Perkins from North Carolina Wildlife Resources Commission

Important Environmental Designations within Pipeline Impact Areas

Natural Diversity Database Areas were also measured and identified using data obtained from CT DEEP’s GIS Open Data Website. Natural Diversity Database Areas are regions where state and federally listed endangered species are known to reside (CT DEEP Open Data GIS).

One hundred percent of the primary work areas for this segment of the pipeline expansion are located within National Diversity Database Areas, reflecting the potential but still obscured damage to habitats this pipeline construction could produce.

Many portions of pipeline work areas are also designated as 2025 Connecticut State Wildlife Action Plan conservation opportunity areas (COA). CT DEEP identifies these regions as recommended places for local institutional and private partners to collaborate to achieve State Wildlife Action Plan Goals. This map specifically highlights regions designated as opportunities for protecting existing wildlife and restoring damaged habitat (Data.ct.gov,  DEEP 2025 Wildlife Action Plan). The proposed location of the pipeline expansion overlaps with both of these regions. While primarily occurring on already disrupted electrical easement may be an argument used to advance the pipeline’s construction, these DEEP data highlight how these regions should be protected, not further degraded. 

Implications: Eversource Profits, Connecticut Residents Pay 

Beyond any ecological impacts, this expansion will cost ratepayers and increase energy unaffordability in the state. Connecticut residents already have the third most expensive electricity bills of any state (Energy Information Administration from John Moritz for CT Mirror). Statewide, total residential gas prices are rising while gas use per residential customer has declined since 1988 due to efficiency improvements (Energy Information Administration). The reason for this increase in cost is apparent through understanding how costs of infrastructure expansion and gas delivery have overtaken the cost of the fuel itself. Statewide, utility companies like Eversource profit from investing in infrastructure due to designated rates of return which incentivize such projects (Future of Heat Initiative). Altogether, this infrastructure expansion is just one small component of Eversource’s strategy to maximize their own profit through infrastructure expansions while placing the burden of rising costs on residents.

Conclusion

The proposed pipeline in Connecticut is just one part of a profit-minded expansion of fossil fuel use conducted by utilities throughout the northeast. This pipeline could create significant harms based on ecological risks from construction, methane leaks, as well as the dangers of gas explosions. This pipeline is a step in the wrong direction for a healthy future, and the people of Middletown and surrounding regions must rally to oppose it. 

This article is an edited version of the report, Pipeline Expansion Under The Connecticut River, by Wesleyan students Aviva Branoff, Lara Barzenji, and Sasha Lovell.

To get more involved in the campaign against pipelines visit No Pipeline Expansion (NOPE) Northeast.