On August 25, 2025, the U.S. Food and Drug Administration sent an urgent communication to health care providers and facilities across the country. The subject: hyperbaric oxygen therapy devices were causing serious injuries and deaths, and the root cause remained unknown. The letter, posted publicly on the FDA’s medical device safety portal, marked one of the most forceful safety communications about HBOT equipment in recent years—a stark reminder that even established medical technologies carry risks when protocols slip.
What Triggered the Warning
The FDA’s letter came after the agency received reports of fires involving hyperbaric oxygen therapy devices that resulted in serious harm to patients and, in some cases, fatalities. Hyperbaric chambers operate by delivering 100% oxygen at pressures higher than normal atmospheric levels—typically between 2.0 and 2.4 atmospheres absolute (ATA) for clinical treatments. This combination of high-pressure oxygen creates an inherently hazardous environment where ignition sources that would be benign under normal conditions can trigger catastrophic fires.
“The FDA is aware of recent reports of fires that occurred with HBOT devices that resulted in serious injuries and deaths,” the agency stated. “Currently, the root cause of these events is not known.” This uncertainty—rare for an FDA safety communication—underscores the complexity of investigating incidents in specialized medical equipment where multiple factors, from electrical grounding to material compatibility, could contribute to failure.
The Heightened Fire Risk in Oxygen-Rich Environments
Hyperbaric oxygen therapy creates conditions that fundamentally alter fire behavior. At elevated pressures, oxygen concentration in the chamber atmosphere increases dramatically. Materials that resist ignition in normal air—cotton fabrics, certain plastics, even human hair—can become flammable. The energy required to ignite a fire drops significantly, and once ignited, flames spread with terrifying speed.
The FDA’s letter explicitly warns providers about this physics: “Be aware that there is a heightened risk of fire with use of oxygen at a high concentration.” This is not theoretical. Historical incidents in hyperbaric medicine, including a 2009 chamber fire in Florida that killed a patient and a firefighter, have demonstrated how quickly situations escalate when ignition occurs in pressurized oxygen environments.
Specific Recommendations for Providers
The FDA outlined eight specific recommendations for health care providers and facilities operating hyperbaric equipment. These directives go beyond general safety advice—they represent minimum standards for safe operation:
Review manufacturer instructions for every device. Each hyperbaric chamber model has specific operational parameters, contraindications, and safety protocols. The FDA emphasizes that providers must not assume familiarity with one device translates to another.
Implement rigorous fire prevention measures. This includes ensuring proper grounding equipment, maintaining strict protocols for prohibited items, and controlling static electricity through appropriate clothing requirements. The FDA specifically notes that patients must wear clothing made of hyperbaric-compatible materials—typically 100% cotton—while wool and synthetic fabrics that generate static should be avoided.
Maintain comprehensive staff training. Operators must receive proper training not just in routine chamber operation but in emergency procedures. The FDA stresses that training must be ongoing, not a one-time certification event.
Ensure continuous patient monitoring. Patients cannot be left unattended during HBOT sessions. The FDA requires proper supervision for the entire treatment duration, with staff trained to recognize and respond to emergencies.
Follow manufacturer-recommended maintenance. Cleaning procedures, maintenance intervals, and safety checks must adhere strictly to manufacturer specifications. Deferred maintenance in hyperbaric medicine is not a cost-saving measure—it is a safety hazard.
Control prohibited items. Electronic devices, static-generating materials, and other potentially dangerous items must be excluded from the chamber environment. The FDA notes that some items may require additional grounding measures even if permitted.
The Regulatory Context: Class II Medical Devices
The FDA classifies hyperbaric oxygen therapy devices as Class II medical devices, cleared through the 510(k) premarket notification process. This classification recognizes that HBOT equipment carries moderate risk requiring special controls to ensure safety and effectiveness. Providers can verify FDA-cleared devices by searching Product Code CBF in the FDA’s 510(k) database.
This regulatory framework places significant responsibility on device manufacturers to design safe equipment and on health care facilities to operate that equipment correctly. The August 2025 letter signals that the FDA believes some facilities may be falling short on the operational side—whether through inadequate training, poor maintenance practices, or failure to follow established protocols.
Reporting and Ongoing Surveillance
The FDA’s communication includes a strong call for adverse event reporting through its MedWatch program. Health care providers who experience or suspect device-related injuries are urged to file voluntary reports. Device manufacturers and user facilities face mandatory reporting requirements under Medical Device Reporting regulations. This surveillance data will prove crucial for identifying patterns that could explain the unknown root causes behind recent incidents.
The agency committed to continued collaboration with manufacturers and professional societies—including the Undersea and Hyperbaric Medical Society—to encourage training and safe device use. Additional safety communications may follow as investigations progress.
What Patients Should Know
For patients considering or currently receiving hyperbaric oxygen therapy, the FDA’s letter does not suggest abandoning treatment for legitimate medical indications. HBOT remains FDA-cleared for specific conditions including decompression sickness, carbon monoxide poisoning, certain non-healing diabetic wounds, late radiation tissue injury, gas gangrene, and others. When administered properly in accredited facilities, the therapy has a strong safety record built over decades of clinical use.
However, patients should feel empowered to ask questions about safety protocols. Is the facility accredited? What training do operators receive? What fire suppression systems are in place? Are patients required to wear cotton clothing, and are electronic devices strictly prohibited in the chamber? Reputable providers welcome these questions and maintain transparent safety practices.
Patients should also be wary of facilities making claims beyond FDA-cleared indications. The same letter that warns about device safety follows years of FDA communications cautioning against using HBOT for unproven conditions—autism, Alzheimer’s disease, cancer, Lyme disease, cerebral palsy, multiple sclerosis, and general wellness or anti-aging applications. Facilities promoting these uses may be less likely to adhere to rigorous safety standards for cleared indications.
Industry Standards and Professional Guidance
The FDA’s recommendations align with established industry standards, particularly the National Fire Protection Association’s NFPA-99-2024 Health Care Facilities Code and the American Society of Mechanical Engineers’ ASME PVHO-1-2023 Safety Standard for Pressure Vessels for Human Occupancy. These documents, developed by technical experts and regularly updated, provide detailed guidance on hyperbaric facility design, operation, and safety that goes beyond FDA regulatory requirements.
Professional societies including the Undersea and Hyperbaric Medical Society have long emphasized safety training and facility accreditation. The FDA’s letter reinforces this existing professional consensus while adding the weight of federal regulatory authority to calls for stricter adherence to safety protocols.
Looking Forward
The FDA’s August 2025 safety communication serves as both warning and roadmap. For an industry that has seen expanding interest—driven partly by wellness marketing and celebrity endorsements—the letter is a reminder that hyperbaric oxygen therapy is fundamentally a medical intervention requiring medical-level safety standards. The fires, injuries, and deaths reported to the FDA represent failures somewhere in the chain of manufacturer design, facility protocols, or individual practice.
As investigations continue and more data becomes available, the FDA has committed to keeping providers and the public informed. For now, the message is clear: hyperbaric oxygen therapy saves lives and limbs when used appropriately for cleared indications, but only when the devices delivering that therapy are operated with the respect their power demands. The margin for error in a pressurized oxygen environment is zero.