Study Links Aliso Canyon Gas Leak to Increased Risk of Low Birth Weight Babies

In a recent study conducted by UCLA researchers, women residing within a 6.2-mile radius of the Aliso Canyon Natural Gas Storage Field faced a significantly higher risk of delivering low-birth-weight babies following the catastrophic gas leak that occurred in late 2015. The Aliso Canyon disaster, which lasted from October 23, 2015, to February 11, 2016, released approximately 109,000 metric tons of methane along with toxic substances like benzene and heavy metals into the atmosphere near the Porter Ranch neighborhood in Los Angeles County. Residents reported foul odors, oily mists, and various health issues during and after the event.

The study analyzed birth records in Los Angeles County from October 2010 to October 2019, totaling over one million births. It specifically focused on 666 births among women living within the impact zone who were exposed to the gas leak during their third trimester. Findings showed that 9.6% of these babies were born with low birth weight (less than 5.5 pounds), compared to 6.6% in the same area before the blowout. During the leak, the rate increased by approximately 45.5%. Outside the impact zone, the rate was slightly lower at 6.8%, but still showed a 41.2% increase during the leak period.

Moreover, when considering only term low birth weight cases—babies born at full term but under 5.5 pounds—the prevalence was 66% higher during the blowout. The highest risk was observed in the sections of the impact zone where gas concentration was most intense, with 11.1% of women experiencing low-birth-weight deliveries—more than 70% higher than previous years.

Environmental sampling confirmed elevated levels of pollutants like heavy metals and benzene during the crisis, with peak methane emissions comparable to the daily output of 4.5 million vehicles. Low birth weight is associated with adverse developmental outcomes, health issues later in life, and increased susceptibility to conditions such as hypertension, diabetes, and heart disease.

Lead researcher Kimberly Paul emphasized that the precise nature of the gas leak allowed for an accurate assessment of its health impacts. She indicated that the findings strongly suggest that the environmental pollution from the blowout directly contributed to the increased incidence of low birth-weight babies. The study highlights the importance of understanding how environmental disasters impact fetal development and long-term health, urging further research into both immediate and lasting health effects.

Following the event, the prevalence of low-birth-weight babies in the impacted area returned to normal levels, indicating potential for recovery. Experts believe that environmental and prenatal health are closely linked, and this incident underlines the need for stricter regulations to prevent future toxic exposures during pregnancy. The UCLA team continues to investigate the short- and long-term health consequences of the Aliso Canyon gas leak.

This research contributes valuable evidence to the ongoing discussion about environmental safety, public health, and regulatory policies surrounding natural gas facilities. Community members and health professionals are encouraged to consider the impacts of such disasters when planning health interventions and regulatory reforms.

Source: https://medicalxpress.com/news/2025-09-large-birth-weight-babies-born.html