Nearly Half of On-Duty Firefighter Deaths Are Heart-Related
More on-duty firefighters are dying from heart problems than previously known. A new study from Cedars-Sinai's Smidt Heart Institute, published October 21, 2026 in the medical journal JACC: Advances, found that 43% of on-duty firefighter deaths in the United States were cardiac-related.
According to the researchers, one of the most common warning signs can slip past a standard annual physical. California lawmakers saw the risk long ago. Under Labor Code section 3212, a firefighter's heart trouble is presumed to be caused by the job. This study gives that law new medical support.
What the Study Found
The researchers reviewed U.S. Fire Administration records covering 3,401 on-duty firefighter deaths from 1990 through 2025. Their main findings:
- 43% of on-duty deaths were cardiac. Nearly half of all firefighter deaths in the line of duty were cardiac in origin.
- The share keeps rising. From 1990 to 2019, total on-duty deaths fell, but the odds that any given death was heart-related rose about 2.2% a year. In the general U.S. population, the trend ran the other way: cardiac deaths fell about 1.3% a year as a share of all deaths.
- Enlarged heart muscle was more common than blocked arteries. In the deaths where autopsy findings were available, 79% showed left ventricular hypertrophy (LVH), a thickening of the heart's main pumping chamber. Obstructive coronary artery disease appeared in 57%.
The autopsy figures come from a smaller group: about a third of 803 deaths investigated by the federal Fire Fighter Fatality Investigation and Prevention Program between 1997 and 2022.
As the study's senior author, cardiologist Alan Kwan, MD, put it, prevention of on-duty cardiac death has not kept pace with other areas of firefighter safety.
The Screening Gap: Why Annual Physicals May Miss It
Most fire departments rely on exercise stress tests to check firefighters' hearts. A stress test is good at finding blocked arteries. It is not designed to find an enlarged or thickened heart muscle, which was the most common finding in this study.
Firefighting makes this harder. Firefighters train hard, and athletic training naturally builds heart muscle. That healthy adaptation can mask thickening caused by a dangerous underlying condition.
The researchers suggest national firefighter health guidelines may need to add screening for excess heart muscle mass. They also say it is not yet clear why firefighters appear to be at higher risk for this condition, and more research is needed.
California's Heart Trouble Presumption
California law already treats heart disease in firefighters as a job injury. Under Labor Code section 3212, heart trouble that develops or shows itself while a firefighter is in service is presumed to have arisen out of the job. The firefighter does not have to prove that a specific fire, call or exposure caused it.
Key points of the presumption:
- It covers "heart trouble" broadly. That includes coronary artery disease, heart attacks, arrhythmias and structural conditions such as an enlarged heart.
- It continues after you leave the job. The presumption extends for three months for each full year of service, up to five years after retirement or separation.
- Your heart condition cannot be blamed on something before the job. The law bars attributing the heart trouble to a disease that existed before employment.
- No apportionment. Once the presumption applies, permanent disability cannot be reduced by blaming part of it on non-work factors such as age, genetics or lifestyle.
- It can be challenged. The employer may try to rebut the presumption with other evidence, which is why strong medical evidence still matters.
The Cedars-Sinai study gives that medical evidence new support. It shows that heart muscle thickening and coronary disease are common among firefighters who die on duty, and that the share of cardiac deaths is rising even as firefighting becomes safer in other ways. For more on how presumptions work, see Special Labor Code Sections: Presumptive Industrial Injuries.
What Firefighters Should Do
- Ask your doctor about more than a stress test. If you have high blood pressure, chest symptoms or a family history of heart disease, ask whether an echocardiogram or other imaging makes sense.
- Keep copies of your medical records. Annual physicals, test results and any cardiology findings can matter later in a claim.
- Report heart symptoms and diagnoses. If you are diagnosed with heart trouble while working, or within the post-service window, report it to your employer and file a claim.
- Don't assume a denial is final. Employers and insurers sometimes argue a heart condition is genetic or lifestyle-related. The presumption puts the burden on them to prove it.
- Talk to a workers' compensation attorney. Presumption cases have specific rules on eligibility, timing and evidence.
What the Study Does Not Show
The study tracks patterns across thousands of deaths. It does not prove that firefighting caused heart disease in any one person, and it does not measure how much smoke, heat, exertion or stress each contributed.
That is exactly why California's presumption matters. The law does not require a firefighter to prove those links one case at a time.
Talk to GEKLAW
GEKLAW has represented California firefighters and public safety workers for decades. If you have been diagnosed with a heart condition, call 213.739.7000 or request a free case evaluation online.
Sources
- Joung SY, Kwan AC, et al. Temporal Trends and Autopsy Correlates of Duty-Related Cardiac Death in Firefighters. JACC: Advances, October 21, 2026.
- Cedars-Sinai: Nearly Half of On-Duty Firefighter Deaths Are Heart Related
- American College of Cardiology: On-Duty Firefighter Cardiac Deaths Highlight Potential Screening Gaps
- California Labor Code section 3212
