A Cedars-Sinai analysis of its emergency department data found that visits for general illness, heart attacks and pulmonary illness rose sharply in the 90 days after the Eaton and Pacific Palisades fires began in January 2025, even as overall ER volume stayed roughly in line with prior years. Researchers said fine particles in wildfire smoke and stress could be contributing factors, and reported that abnormal blood test results linked to general illness more than doubled during the same period.
A new study from Cedars-Sinai reports a sharp rise in certain emergency department presentations in the months following the January 2025 wildfires in Los Angeles, including the Eaton and Pacific Palisades fires.
According to Cedars-Sinai’s report on the study, investigators analyzed visits to the Cedars-Sinai Emergency Department on the medical center’s main campus, which the institution says is located about 10 miles from Pacific Palisades and about 20 miles from Altadena—areas tied to the largest fires that ignited in January 2025.
Researchers examined emergency department visits during the 90 days after the fires began—from Jan. 7 to April 7, 2025—and compared them with visits from the same calendar period in each year from 2018 through 2024. Cedars-Sinai said total ER visits during that 2025 window did not differ significantly from previous years, but several categories rose markedly.
Compared with the prior seven-year average for the same dates, Cedars-Sinai reported a 118% increase in emergency visits coded as general illness, a 46% increase in visits related to heart attacks, and a 24% increase in visits tied to pulmonary illness.
“Wildfires that spread into urban areas have proven to be extremely dangerous because of how quickly they move and what they burn and release into the environment,” Susan Cheng, MD, MPH, the study’s senior author, said in the Cedars-Sinai release. Cheng added that “fine particles released by wildfires can enter the body and cause injury, particularly to the heart and lungs,” and that stress related to the fires “may also contribute to a broad range of health issues.”
The analysis also found that abnormal blood test results associated with general illness “more than doubled” during the 90-day period in 2025 compared with the same timeframe in earlier years. Joseph Ebinger, MD, MS, the study’s first author, said in the release that such abnormalities “could indicate that the body is responding to an external stressor such as toxins in the air,” while emphasizing that further research is needed.
Cedars-Sinai said the work is part of the broader LA Fire HEALTH Study, a collaboration that it said will track health impacts over the next 10 years and includes researchers from Cedars-Sinai, the Harvard T.H. Chan School of Public Health, USC’s Keck School of Medicine, Stanford University, UCLA, UC Davis, UC Irvine, the University of Texas at Austin, and Yale University.
