The noise was so loud, ShawnaLee Kwashnak thought a jet engine had landed in her driveway.
“I remember being woken up from a sound sleep that, in that moment, I could only describe as a tornado or freight train smashing into my house, except there was no storm,” Kwashnak said.
“Then the next thought is, ‘What the heck is a jet engine doing in my driveway?’ It was that loud. It vibrated the house,” she said.
The sound started after midnight on July 12. It woke up residents in Oxford, Middlebury and Naugatuck and lasted for approximately 45 minutes.
“By the time it stops, it's such a relief. But then you’re lying there wondering, ‘What happened and is it going to happen again?’” she said. “Nothing you could think of made any sense.”
Kwashnak lives in Middlebury, about two miles away from a compressor station in Oxford. The facility increases the pressure of natural gas, helping it move long distances along the Algonquin Gas Transmission pipeline – a 1,131-mile system that transports natural gas through New England, New York and New Jersey.
On the night of July 12, the Oxford compressor station had two equipment failures, according to incident data collected by the U.S. Department of Transportation, Pipeline and Hazardous Materials Safety Administration.
The data shows malfunctions caused the release of more than 35 million cubic feet of natural gas in less than an hour. That's roughly the same amount of natural gas used by 450 Connecticut homes in an entire year, according to 2024 data from the U.S. Energy Information Administration.
“That's a huge amount of a gas that we ought not to be breathing in,” said Kirsten Ek, a hospitalist physician with Connecticut Health Professionals for Climate Action.
The incident is the largest release of natural gas in Connecticut reported to the federal government in the last 10 years and in the top 10 percent of all nationwide releases reported since 2010.
Residents near the Oxford plant are raising concerns about a lack of communication after the incident.
The Oxford release happened as another compressor station in Connecticut, located in Brookfield and operated by Iroquois Pipeline Operating Company, has been making headlines as local residents fight a proposal to expand that facility.
Oxford station experienced two equipment failures on July 12
Both equipment failures involved the Oxford station’s emergency shutdown system, according to the federal government's incident data. The system is designed to respond to abnormalities like unintentional pressure drops or natural gas leaks.
The first malfunction was a loose connection on a newly installed emergency pull switch that triggered the station to go into emergency shutdown mode at approximately 12:47am.
When an emergency shutdown system works properly, it automatically stops the compressor units, isolates the station away from the pipeline, and vents the remaining natural gas through the station’s discharge pipes.
But a valve meant to seal the station off from the pipeline failed to close completely, causing natural gas to flow from the pipeline, through the station’s discharge pipes, and out into the atmosphere for approximately 53 minutes.
The loud jet engine-like sound that woke up residents was likely caused by the rapid release of natural gas moving from high to low pressure as it left the pipeline and entered the atmosphere, according to Talor Musil, field manager at the Environmental Health Project, a nonprofit organization that helps residents whose health has been impacted by oil and gas development.
The valve remained open until approximately 1:40am, when personnel were able to manually close it.
Enbridge, the company that owns the natural gas pipeline, told Connecticut Public in an email that the station “experienced an unplanned outage” and that “at no time was there a threat to public safety.”
Residents and activists say they were never told how much natural gas was released or what steps have been taken to ensure this doesn’t happen again.
“It should be transparent and there should actually be an apology,” Kwashnak said.
“You’re in your home, in your yard, and you’re supposed to feel safe. Something like that goes on, it changes things,” she said.
How natural gas affects the environment and your body
Natural gas is a fossil fuel that’s mostly made up of methane, a powerful greenhouse gas that contributes to global warming by trapping heat in the earth’s atmosphere.
It’s also highly combustible.
“It is known to cause violent explosions when it's in high concentration and catches fire,” said hospitalist physician, Kirsten Ek.
When it comes to health impacts, methane is known to displace oxygen in the body. Low or moderate concentrations of methane can cause dizziness and nausea. High concentrations can worsen headaches, cause confusion, loss of coordination, faster breathing, heart stress and eventually a loss of consciousness, according to Ek.
“The people around that release may have experienced a lot of those early symptoms, and if they were close enough into the high concentration, they may have experienced more intense headaches, nausea, confusion, things like that,” Ek said.
Methane can also cause reactions that create ground-level ozone, another greenhouse gas that causes respiratory issues.
“When you breathe it in, [it's] toxic to the lungs. It’s like getting a sunburn inside your lungs,” Ek said.
Connecticut already has some of the highest levels of ozone pollution in the United States, with over half a million children breathing in unhealthy air, according to a new report by the American Lung Association.
Middlebury resident Kwashnawk said her throat was burning the day after the release, a possible symptom of being exposed to another pollutant in natural gas – volatile organic compounds, also known as VOCs.
“Short-term effects that could occur include, eye, nose, throat irritation, headaches or nausea, even loss of coordination or dizziness,” said Musil at the Environmental Health Project.
“There absolutely is risk involved,” she said.
Who’s accountable and what happens next?
When natural gas is released from a compressor station during an emergency shutdown, it’s referred to as a ‘blowdown’ rather than a ‘leak’ or ‘spill’.
That’s because the natural gas is intentionally released as part of the emergency shutdown process.
Blowdowns are not directly regulated by Connecticut’s Department of Energy and Environmental Protection, according to an agency spokesperson, who stated that blowdowns fall under the jurisdiction of the U.S. Department of Transportation.
A federal agency under that department, PHMSA, is responsible for setting and enforcing standards related to the safe transportation of energy. It also collects data on unintentional gas releases that exceed 3 million cubic feet.
But the agency declined to comment for this story, referring Connecticut Public to the Public Utility Regulatory Authority (PURA).
PURA also declined to comment, stating the issue might come before them for adjudication.
Although PURA is known for regulating utilities in Connecticut, it’s also responsible for pipeline safety in the state.
It’s not immediately clear if the blowdown violated the Clean Air Act, which regulates air emissions and allows the Environmental Protection Agency to establish air quality standards.
Any deviation from the act is required to be reported to DEEP within 24 hours or 10 days.
“At this time, the operator has not submitted a Clean Air Act deviation report to DEEP in relation to this matter,” a DEEP spokesperson said.
Environmental activists from the the Sierra Club's Connecticut chapter say they’d like to see more transparency around blowdowns, including publicly available information on how much methane gas is released and notifying nearby residents.
“These events can be frightening to those who live nearby,” said Samantha Dynowski, state director of Sierra Club Connecticut, in a statement.
“They can also have dangerous impacts on those with pre-existing conditions who are especially vulnerable to poor air quality,” she said.
Áine Pennello is a Report for America corps member, covering the environment and climate change for Connecticut Public. Isabelle Marceles contributed to this report.
