Aliso Canyon Gas Leak: A Decade of Lingering Concerns

On October 23, 2015, a significant gas leak at the Aliso Canyon underground storage facility near Porter Ranch, California, erupted, marking the largest methane leak in U.S. history. Over the course of nearly four months, the leak released more than 109,000 metric tons of methane into the atmosphere, displacing approximately 8,000 families in the surrounding area. As the tenth anniversary of this disaster approaches, residents continue to grapple with the lasting effects of the blowout, compounded by ongoing health concerns and a slow-moving response from health authorities and researchers.

Recently, Craig Galanti, a long-time resident of Porter Ranch, received an alarming text alert indicating elevated levels of methane gas—recorded at 249 parts per million, significantly higher than typical levels. This notification, sent on October 3, 2025, came from the Porter Ranch Community Air Monitoring Project, established to provide real-time data following the 2015 incident. Galanti, who is also part of the Community Advisory Group for the UCLA-led Aliso Canyon Disaster Health Research Study, quickly informed his wife to avoid returning home until more information was available.

While the initial alert was later deemed erroneous, the incident reignited fears in a community that has lived with the consequences of the gas leak for nearly a decade. Many residents still report persistent health issues, including headaches, dizziness, and respiratory problems, leading to frustration over the lack of definitive answers and timely communication from health officials.

What Happened During the 2015 Blowout?

The leak originated from Well SS-25 at the Aliso Canyon facility, which was found to have suffered from external corrosion that compromised the well casing. This technical failure allowed natural gas to escape into the environment, prompting widespread reports of health complaints among residents. The Southern California Gas Company (SoCalGas), which operates the facility, faced numerous lawsuits from nearly 36,000 plaintiffs seeking damages for personal injuries and property losses.

In the aftermath, many residents reported feeling abandoned as they struggled to obtain clear information about the risks posed by the gas leak. Initial alerts about the leak came not from SoCalGas or local health officials but through community discussions on social media. Residents reported a strong odor and various health symptoms, only to be met with vague reassurances from authorities regarding the safety of the air quality.

Despite mobilization efforts to monitor air quality and provide evacuation guidance, many residents experienced confusion and a deepening mistrust of the messages being communicated. The Los Angeles County Department of Public Health initially linked health complaints to odorants used in natural gas, stating that exposures were not expected to result in long-term health problems. However, the growing list of symptoms contradicted these claims, leaving residents feeling unheard and frustrated.

Current Health Studies and Ongoing Concerns

As the community marks a decade since the blowout, a comprehensive health study led by UCLA researchers is still underway, with results expected in October 2027. Preliminary findings suggest that pregnant women living near Aliso Canyon during the incident were more likely to deliver low-weight babies. Researchers analyzed over 1 million birth records from 2010 to 2019, identifying significant correlations between exposure to harmful pollutants and adverse fetal outcomes.

UCLA professor and principal investigator Michael Jerrett highlighted the complexity of proving direct health impacts from the leak, stating that understanding exposure levels is essential for establishing causality. As researchers continue to assess health outcomes through various methodologies, including community health surveys and clinical exams, advocates within the community express concern that the focus has not sufficiently addressed ongoing emissions from the site.

Dr. Jeffrey Nordella, a physician who treated residents during the leak, noted a rise in patients with unusual symptom combinations that did not align with typical diagnoses. He criticized public health guidance that discouraged further investigation of potential chemical causes related to the leak. The impacts of the blowout remain a point of contention, with many residents feeling that their health concerns are yet to be fully acknowledged or addressed.

In response to community advocacy, public health agencies have implemented changes aimed at improving oversight and safety protocols. Legislation such as Senate Bill 1137, enacted in 2022, mandates buffer zones between oil and gas operations and residential areas. Furthermore, the California Geologic Energy Management Division (CalGEM) has enacted stricter regulations for underground gas storage facilities in the wake of the disaster.

Despite these efforts, skepticism lingers among residents. Many feel that the information provided by SoCalGas and health authorities has been inadequate, leading to a persistent sense of unease about their safety. The recent erroneous alert regarding methane levels further exacerbated these fears, highlighting the fragile trust between the community and regulatory agencies.

As the tenth anniversary approaches, residents like Galanti remain vigilant, navigating their lives with a heightened awareness of potential health risks. “Before all this, I just trusted the government. I have no trust in the government anymore,” he stated, reflecting the sentiments of many in the community who continue to seek clarity and accountability in the aftermath of the Aliso Canyon gas leak.