SANTA BARBARA, Calif., June 9, 2025 /3BL/ - A new study reveals how wildfires are particularly dangerous for Californians with significant health conditions, with one in five respondents reporting harm to their health from delays in medical care after the Oak Fire.

Led by researchers from Harvard Medical School-affiliated Beth Israel Deaconess Medical Center, Direct Relief, and Mariposa County Health and Human Services Agency, the study focuses on the 2022 Oak Fire in rural Mariposa County—but its findings resonate statewide, as wildfires, evacuations, and public safety power shutoffs increase in frequency.

“Interruptions to health care access during and in the aftermath of disasters impact health long after the initial insult,” the authors write. The study appears in the journal Disaster Medicine and Public Health Preparedness (Cambridge University Press) and is available at https://doi.org/10.1017/dmp.2025.10063.

The study “underscores the worrisome disruptions in health care access faced by medically vulnerable populations across the US during disaster,” the paper says. “That 1/5 missed routine appointments, and that the vast majority could not re-establish care for weeks or months deserves urgent attention.”

Researchers surveyed Mariposa County residents who were enrolled in the Support and Aid For Everyone (SAFE) program - a county program that assists those with self-identified special needs during

emergencies, and comprises largely older adults and those with chronic medical conditions and mobility needs.

Among the respondents – with a median age of 78 years old, nearly ¾ of whom had mobility issues, and nearly half of whom needed help with activities of daily living – the study found major gaps in emergency readiness, access to information, and continued medical care:

• 53% of people using life-sustaining electricity-powered medical devices (like oxygen concentrators) weren’t enrolled in Pacific Gas and Electric’s Medical Baseline Program, which prioritizes them for power shutoff alerts and offers financial relief.
• 1 in 5 (21%) missed or delayed medical appointments due to the fire, and 45% of those people reported months-long delays in receiving care.
• 21% reported harm to their health from delays in medical care related to the fire.
• The people who experienced the most delays had more medical conditions (mean 4.1 vs. 2.4) and used more medical devices (median 4 vs. 2), making them more vulnerable to loss of care.
• 75% reported having evacuated from a previous fire, and 33% reported multiple prior evacuations.

With over 230,000 Medicare beneficiaries in California relying on powered medical devices, the study raises red flags far beyond Mariposa County—from seniors in Fresno to immunocompromised residents in Los Angeles.

Asked to identify the most trusted sources of reliable information about evacuations and fires, 77% pointed to county officials, compared to 57% for state officials and 23% for TV news. The Oak Fire information they found most useful was fire location and progress, road closures, risks to the household, shelter locations, and evacuation routes.

As California enters another active fire season, the authors make the case that wildfire response must include protecting access to care for those who can’t go without it. “Preparedness must focus not only on response to disasters, but on preempting health care disruptions at home—through improved outreach and communication, access to back-up power and supplies, and pathways to efficiently reinstate health services,” they write.

Media Contacts:

Beth Israel Deaconess Medical Center: Katie Brace, [email protected]

Direct Relief: Paul Sherer, [email protected]

Mariposa County Health and Human Services Agency: Kazzy Cunningham, [email protected]