PUBLICATION OF RESULTS

On September 12, 2025, our study of birth outcomes was published in a leading journal, Science Advances. This is the first study published by the Aliso Canyon Disaster Health Research Study. The study found that pregnant women living near the Aliso Canyon gas blowout were more likely to have babies with low birth weight, and it suggests the increase could be attributed to the disaster.

The publication is available in full on the Science Advances website and a summary can be found in the press release on our study website. The UCLA research team presented preliminary findings for this analysis at Community Meeting #3, which was held February 20, 2024.

In addition, we have submitted two manuscripts to scientific journals for peer review and publication:

• Focus groups on mental health effects of the disaster is in consideration for publication and includes a summary of mental health symptoms experienced at the time of the disaster as well as long-term impacts identified by focus group participants, which informed the resident health survey.
• Characterizing the gas blowout using satellite images has been accepted for publication in Environmental Research Communications and includes findings from analysis of satellite and aircraft images taken during the disaster, used to measure the extent of the methane plume emitted during the blowout.

Preliminary results for these analyses were presented at Community Meeting #4, which was held November 14, 2024.

We are now preparing two additional manuscripts for journal submission:

• Study of emergency department visits as a method of measuring the impact of the disaster on residents’ health (preliminary results were presented at Community Meeting #5, which was held May 13, 2025).
• Risk assessment methodology (analysis methods were presented at Community Meeting #4).

MAJOR STUDY MILESTONES MET

Activities, accomplishments, and status updates for the first half of this year include:

• Finalized the framework for analysis of California Cancer Registry which was presented to the Scientific Oversight Committee (SOC) this fall and requested additional recently released years of data from the state.
• For the upcoming Resident Health Survey (RHS) and Clinical Assessments, we are finalizing the following tasks:
  • Preparing recruitment materials (letters, fliers) for mailing
  • Organizing Clinical Assessment data collection logistics
  • Selecting a representative group of individuals who will receive an invitation to participate in the survey
• Updating the California Health Interview Survey (CHIS) with recently released data and analysis of several key health outcomes, such as asthma and heart disease, for the affected and comparison communities.
• Received Institutional Review Board (IRB) human subjects research approval to begin the RHS and Clinical Assessments.
• Following repeated requests, obtained confirmation from the State of California to provide blood spots for the metabolomics and epidemiological analyses analysis, anticipated in early 2026.
• Completed 2 rounds of field measurements of air pollutants at 40 homes divided between affected and control communities and currently analyzing data from environmental field sampling.
• Finished 6 rounds of natural gas sampling at 22 homes in the affected and comparison communities to be used to analyze the natural gas composition and potential health impacts of indoor exposures to unburned natural gas from appliances.
• Cataloged more than 1,000 data sources acquired for the risk assessment study into an inventory that was posted on the study website.
• Finalized a risk assessment methodology, developed uniquely for estimating the health risks of exposure to the Aliso Canyon Disaster, using data sources from the disaster and other analyses conducted by the study team. We will conduct the risk assessment component of the overall study using this carefully developed methodology.

COMMUNITY ENGAGEMENT

• Study of emergency department visits as a method of measuring impact on resident health.
• Estimates of how pollutants traveled through the air during the blowout.

The recording, presentation, and summary are available on the study website. We appreciate the community’s questions and feedback, which continue to inform and improve the study.

Website Updates and Additional Information
We updated and expanded the website to provide additional information requested by the community. The Study Approach page now includes more detailed information on clinical and metabolomics methods. We also updated the Study Timeline and added an inventory of data sources used in the study. If you have any questions about these updates, please reach out to us through the Contact Us page.

Community Engagement Support and Advice Network (CESAN)
We continue to seek and appreciate feedback about our community engagement efforts from the community and the CESAN. We are in the process of consulting CESAN participants about promotional items and outreach activities for the near-final Health Survey clinical assessments, Community Meeting #5 feedback, and general community awareness and engagement.

We are also looking to expand the network of CESAN participants. Please contact us at alisostudy@ucla.edu if you are interested in helping us increase community awareness about and participation in the study. We welcome community members of all age groups, including high school students seeking volunteer opportunities. See pages 2–5 in our Community Stakeholder Communications Plan (CSCP) for further information about the CESAN.