Craig Galanti was standing in a Costco aisle earlier this month when his phone buzzed with an alert: unusually high levels of methane gas had been detected near his Porter Ranch neighborhood overlooking the San Fernando Valley. The level recorded was 249 parts per million, more than 100 times what’s normally found in the air.
The message, sent Oct. 3, just a few weeks shy of the 10-year anniversary of the Aliso Canyon gas leak on October 23, 2015, came from the Porter Ranch Community Air Monitoring Project — an independent system set up after the 2015 Aliso Canyon blowout to give residents real-time data.
Galanti immediately texted his wife: “Do not go home yet.”
“Your anxiety level goes up significantly,” he said. “ You want to understand immediately as much as you possibly can, so you can make an informed decision.”
About 40 minutes later, he said, another text arrived, this time stating the reading of 249 parts per million had been sent in error.
But by then, Galanti was already scanning air quality websites, checking gas monitors, and slipping back into the fear and vigilance that had never fully gone away.
That flash of fear — and the uncertainty behind it — still haunts many in the northwest San Fernando Valley, where the 2015 Aliso Canyon gas blowout forced the relocation of 8,000 families and spewed more than 109,000 metric tons of methane into the air for nearly four months.
As the Porter Ranch community marks the 10th anniversary of the largest methane leak in U.S. history, a long-awaited health study is still in progress. Researchers and regulators have begun to track potential long-term effects. But residents say the answers are coming too slowly — and the emotional, physical, and institutional fallout of the disaster still shapes their lives today.
What happened in 2015
On October 23, 2015, a leak erupted from Well SS-25 at the underground Aliso Canyon gas storage facility near the Porter Ranch neighborhood. State regulators later found that the blowout was caused by external corrosion that led to a rupture in the underground well casing, likely due to contact with groundwater.
Over the next four months, natural gas spewed into the air, releasing not just methane — the primary component of natural gas — but also other potentially hazardous chemicals. Thousands of residents began reporting headaches, dizziness, nosebleeds and nausea. Many feared exposure to cancer-causing substances like benzene and voiced frustration at the lack of clear information.
Southern California Gas Company (SoCalGas), the gas storage facility’s operator, would later face multiple lawsuits, with nearly 36,000 plaintiffs seeking damages for personal injuries, wrongful deaths and property losses.
In the days after the Aliso Canyon blowout, many Porter Ranch residents said they felt abandoned — confused by the silence from officials and overwhelmed by worsening health problems.
The community’s first alerts about the gas leak at Well SS-25 came not from SoCalGas or public agencies, but from neighbors exchanging Facebook posts about a pungent smell that crept through the neighborhood.
That day, SoCalGas employees discovered a methane leak rising from a deep well drilled in 1953 and repurposed decades later for underground storage. But residents were initially told the smell was due to routine monthly natural gas releases, according to Matt Pakucko, co-founder of the community group Save Porter Ranch, who spoke with a SoCalGas operator a few days after the leak. He recorded the call and later posted it on the group’s Facebook page. It wasn’t until an Oct. 26 community meeting that the company acknowledged the leak. A formal letter didn’t reach most households until Oct. 31.
“The chaos just really ensued because we couldn’t get clear answers to anything. The community was relying upon itself for tidbits,” Galanti said. “The regulators were very late to the area to advise us of what was going on and what the impacts might be. And we learned later the impacts were very significant.”
Though agencies mobilized in the weeks that followed, with air quality monitors, fact sheets, and evacuation guidance, residents said the early messaging was vague, sometimes dismissive, and often contradicted their lived experience.
Officials at Los Angeles County Department of Public Health initially linked symptoms to odorants used in natural gas and noted in a November 2015 factsheet that “exposures to these chemicals are generally not expected to lead to permanent or long-term health problems.” But the list of complaints kept growing: headaches, rashes, nausea, dizziness and fatigue.
“Officials always say, ‘there’s no immediate risk to the nearby communities.’ That’s it,” said Kyoko Hibino, co-founder of Save Porter Ranch. She said public agencies often compared local air readings to Los Angeles’ already polluted air quality, a standard she believes downplayed the true risks facing Porter Ranch residents.
Pakucko said he began experiencing recurring skin rashes on his arms and legs after the blowout, which he attributes to heightened sensitivity from chemical exposure during the leak.
“When you get an overload like that, the body develops a sensitivity to exposures,” he said.
Jeffrey Nordella, a physician who practiced in Porter Ranch at the time, began seeing a surge of patients with unusual symptom combinations that didn’t match common diagnoses.
“A lot of the symptoms really were not what I was used to seeing after years and years of practice for standard diagnosis,” Nordella said Oct. 7. “So all of that said, it just kind of led me to say ‘something else is going on.’”
Nordella accused Los Angeles County Public Health of issuing guidance that discouraged physicians from investigating possible chemical causes — including a March 2016 directive instructing doctors to avoid toxicology screening and instead consider other possible explanations related to air contamination.
A spokesperson from Public Health did not provide a statement in response to Nordella, but the department shared a fact sheet from January 2016 that stated in part, “there are no recommended toxicological tests of blood, urine, or other tissues” for evaluating patients exposed to the gas leak, and that “the only treatment for persistent or unbearable symptoms is removal from the odor. “
The department also pointed to the Aliso Canyon Disaster Health Research Study, conducted by UCLA, which it said is meant to help guide future actions by public agencies, health providers and community groups.
Many families said the lack of timely and transparent communication from SoCalGas and public health agencies in the early days of the Aliso Canyon crisis eroded their confidence.
“You’re jumping into a situation and there’s so much to understand,” Galanti said. “And there’s no solid source of truth for you to make good decisions for the care of your family.”
Officials at Los Angeles County Public Health said the 2015 blowout underscored the importance of policies and response efforts “grounded in both scientific evidence and the lived experiences of those most affected.”
Changes followed the disaster
“Community members in Porter Ranch brought forward firsthand knowledge of health impacts and environmental concerns, which informed the overall response,” the department said in a statement. “Their input not only improved how agencies assessed and managed risks, but also led to meaningful changes in public health policy related to underground gas state regulations.”
Among those changes were stronger regulations from the California Geologic Energy Management Division (CalGEM) — the state’s oil and gas agency — including Senate Bill 1137, a 2022 law requiring buffer zones between oil and gas operations and homes, schools, and other community spaces. County Public Health called these protections “essential in reducing potential health impacts to communities.”
The department also stressed its role in launching and overseeing the ongoing Aliso Canyon Disaster Health Research Study, a $21 million study led by UCLA researchers to investigate the short- and long-term health effects of the blowout and the site’s ongoing emissions.
Public Health said a robust community engagement process was baked into the study’s design from the beginning — shaping the research goals, public meetings, and inclusion of scientific experts not affiliated with regulatory agencies.
“Findings from the Health Study, expected in October 2027,” the department said, “will help inform evidence-based policies that can help reduce the risk to communities from environmental hazards.”
Other state regulators also pointed to post-blowout reforms. The California Public Utilities Commission (CPUC), which shares safety oversight of underground natural gas storage facilities with CalGEM, said in a statement that Aliso Canyon has operated under more stringent rules since gas injections resumed in 2017.
That includes new safety protocols implemented by the CPUC and CalGEM starting in 2017, a comprehensive safety review of all 114 wells at the facility, and updated natural gas storage regulations adopted by CalGEM in 2017 and 2018.
CPUC said it continues to assess the facility’s role in energy reliability and determine whether the Aliso Canyon site is still needed. In its first biennial report released on Oct. 1, 2025, the commission concluded that conditions may allow for a reduction in the facility’s storage capacity — though not full closure.
SoCalGas said it has implemented “multiple safety layers” at the Aliso Canyon facility since the blowout — including new steel tubing in all active wells, real-time pressure monitoring, and daily visual inspections. The utility also said it now operates the site at reduced pressure and conducts continuous methane monitoring in the area.
A SoCalGas spokesperson said the company also created a Community Advisory Council to keep local residents informed, and established an internal safety committee — part of a 2019 legal settlement with state and local agencies— to regularly review well operations.
“Independent regulatory agencies concluded that the Aliso Canyon gas leak did not pose long-term health risks to the public,” the spokesperson said in a statement. “This determination was based on extensive data collected during and after the 2015–2016 incident. Some of the agencies that reviewed this data were Los Angeles County Department of Public Health, California Office of Environmental Health Hazard Assessment, California Air Resources Board, and South Coast Air Quality Management District, among others.”
But many residents and health experts say their view is premature, and that key questions remain unanswered, nearly a decade later.
What we know and what we don’t
A decade later, the full health impact of the Aliso Canyon blowout remains unclear. The most comprehensive effort to answer that question — the public health study led by UCLA researchers — is still underway, with final results expected in 2027.
Researchers published their first peer‑reviewed findings, showing that pregnant women living near Aliso Canyon during the blowout were more likely to deliver low‑weight babies. The study reviewed more than 1 million county birth records from 2010-2019 and identified 666 cases in which pregnant women living within a 6.2-mile-radius impact zone downwind of the facility were exposed to higher levels of harmful pollutants, including heavy metals and chemicals like benzene, which are known to affect fetal development.
In a recent interview, UCLA professor and principal investigator Michael Jerrett said the team is midway through the larger study, which includes monitoring fine particulate matter in homes, analyzing emergency room data, tracking methane via aircraft and satellite, conducting a community health survey, and performing clinical exams such as lung tests, neurological assessments, and urine and blood analyses for chemical exposure.
“The community’s really interested in the health outcomes and the clinical assessments, which is understandable, but we also want to be able to make a reasonable argument that the exposures from the facility are what could be contributing to differences in observed health outcomes,” Jerrett said.
The researchers are also studying whether ongoing emissions from the Aliso Canyon gas storage site pose health risks today.
That’s a question some community advocates say hasn’t received enough attention — especially given residents’ longstanding concerns about persistent odors, off-gassing, and potential toxic exposure even after the well was sealed.
Nordella said the early UCLA findings align with what he observed in his own testing of residents’ blood, urine, and hair samples — including elevated levels of benzene, lithium, and uranium. But he criticizes the UCLA study for researching birth outcomes only to the end of 2019, and for what he views as not going far enough in studying “biomarkers” — substances in the body that indicate the presence of a disease or condition.
“But what about post-blow up?” Nordella said. “What about 2016 to present? What is happening in the community? That’s what we really need to know.”
Jerrett acknowledged that some in the community feel the study is overly focused on exposure levels. But he said understanding how much natural gas people actually inhaled is crucial, because without that scientists can’t prove whether the natural gas leak caused the health effects now being reported.
Nordella, meanwhile, said he has reactivated his medical practice and will begin offering residents the option to undergo biomarker testing. He plans to share more details at an upcoming event marking the 10-year anniversary of the Aliso Canyon disaster, hosted by Save Porter Ranch and Food & Water Watch.
Community trust and skepticism
That desire to know, and the lingering fear of what’s still unknown, continues to define life for many in the northwest San Fernando Valley.
In the years after the blowout, residents pushed for stronger oversight and real-time access to air quality data. In response, the Porter Ranch Community Air Monitoring Project was launched in 2017 as a collaboration between the South Coast Air Quality Management District (AQMD), UCLA, and Argos Scientific, a private firm. The system provides publicly available methane readings and allows residents to sign up for email and text alerts when levels spike.
Funding for the project comes from the South Coast AQMD and the Aliso Canyon Fund Committee — a body formed to oversee the distribution of settlement funds from the 2015 blowout to support community health, environmental monitoring and mitigation efforts.
But that hasn’t erased the doubts of some residents.
“Stuff still comes out of that facility,” said Matt Pakucko, co-founder of Save Porter Ranch. Kyoko Hibino, another co-founder, said years of unanswered questions have left many residents feeling abandoned. “ People are pretty much hopeless, helpless,” she said. “ No one actually helps us in terms of what to do with the chemical in the body.”
Galanti remains wary, especially after he received an automated text alert on Oct. 3 showing a spike of 249 parts per million of methane, which officials at AQMD said was an error due to maintenance and was corrected the same day. According to the agency, the alert went out at 1:20 p.m., and Argos Scientific sent a retraction at 3:40 p.m. after reviewing the data.
Don Gamiles, CEO of Argos Scientific, contracted to provide real-time air quality monitoring after the natural gas leak, said, “This was the first time this has occurred in the about the two and a half years we’ve been running the stations” — technology that measures airborne gases like methane. “So it’s extremely, extremely rare and it was only due to the maintenance of them.”
But for Galanti, the trust is gone.
“As you’re driving up the hill, you put your windows down and you’re like, ‘Do I smell gas? Is it like last time? Is there something going on? Let me check all the monitors that I can access. ’”
He later added: “Before all this … I just trusted the government. I have no trust in the government anymore. I have no trust in these regulators.”