Hyperbaric oxygen therapy can be safe and useful when run at the right clinic for the right use. It can also cause real harm — barotrauma, oxygen toxicity, fire injury — when run at clinics that skip protocols or oversell off-label use.
This checklist walks through what to verify before booking your first session:
- Accreditation
- Medical director credentials
- Chamber FDA clearance
- Technician certification
- Safety protocols
- The right questions to ask
- The red flags that should make you walk out
The checklist is built on the standards used by the Undersea and Hyperbaric Medical Society and the NFPA 99 fire safety code. These are the references that distinguish credible clinics from the rest.
What to verify before booking
The verification list breaks into five categories. Run through each before paying any deposit.
1. UHMS accreditation status
UHMS accreditation is the most reliable signal of a credible HBOT facility. Roughly 180 of the 1,588 US HBOT centers tracked in 2026 carry UHMS accreditation — about 11%.
UHMS-accredited clinics meet four hard standards:
- A medical director trained in hyperbaric medicine
- CHT or CHRN-certified technicians on staff
- Documented emergency and fire response protocols
- Annual chamber inspections by qualified third-party inspectors
The accreditation is voluntary. The other 89% of US HBOT centers may still run to high standards.
Many do not. Ask the clinic directly: "Are you UHMS-accredited?" Honest answers are simple yes or no, plus the year accredited.
2. Medical director credentials
Every legit clinical HBOT program has a medical director on staff. For FDA-approved uses, billing needs physician supervision per Medicare NCD 20.29.
Check the following:
- The medical director's name and active medical license
- Training in hyperbaric medicine (UHMS, ACHM, or equivalent)
- Whether the director is physically present during your sessions or on call
- Whether the director can be reached if you have an adverse event
Wellness clinics offering soft-chamber mild HBOT often do not have a hyperbaric-trained medical director on site. This is legal because soft chambers are Class C consumer devices. But it means the medical oversight layer is thinner than at a hospital-grade clinical facility.
3. Chamber FDA 510(k) clearance
Every legal HBOT chamber sold in the US has an FDA 510(k) clearance number. Use the FDA 510(k) database (2026) to verify before treatment. See complete FDA-cleared chambers list for the complete chamber-by-chamber list.
Confirm:
- The chamber make and model match what the seller claims
- The clearance is active, not withdrawn or recalled
- The indications for use match what the clinic is treating
- The chamber pressure rating is appropriate for the indication
Hard-shell hospital chambers operate at 2.0 to 3.0 ATA under FDA Class A clearance. Major builders include Sechrist Industries, Perry Baromedical, ETC Biomedical, and Healing Chambers International.
These are the chambers used in the trials that produced the 14 FDA-approved uses.
Soft-shell consumer chambers from OxyHealth, Newtowne Hyperbarics, and Summit to Sea operate at 1.3 ATA under FDA Class C clearance for one indication only — acute mountain sickness. Other uses are off-label.
4. Technician certification
HBOT techs should hold a CHT (Certified Hyperbaric Technologist) or CHRN (Certified Hyperbaric Registered Nurse) credential. Both are run by the National Board of Diving and Hyperbaric Medical Technology.
Ask:
- Are your operating technicians CHT or CHRN certified?
- How many sessions has the assigned tech run?
- Is there a tech on site for every dive, or do they monitor remotely?
- What is the tech's response time for in-chamber emergencies?
For hospital programs, certified techs are the norm. For wellness clinics with soft-chamber mild HBOT, cert rates vary widely. Many run sessions without certified techs at all.
5. Safety protocols
Real HBOT clinics follow NFPA 99 standards (2024 edition). These rules cover fire prevention, oxygen handling, and emergency response.
The clinic should be able to walk you through:
- Pre-dive screening (synthetic clothing, electronics, jewelry, lotions)
- Fire suppression systems and last drill date
- Emergency evacuation procedures
- Oxygen toxicity seizure response protocol
- Documented adverse event reporting to the FDA
Vague answers or visible shortcuts are reasons to leave.
Red flags that should make you walk out
These are signals that a clinic prioritizes selling over safety. Spot any of these, and pick a different provider.
Claims that HBOT is a proven fix for off-label conditions. No clinical body endorses HBOT as established care for autism, TBI, or anti-aging. The 2016 systematic review on autism concluded HBOT evidence does not support clinical use.
Anti-aging marketing often cites the Hachmo 2020 telomere study at Tel Aviv University. That study had 35 people and has not been replicated.
"Our soft chambers produce the same effects as hospital HBOT." They do not. The pressure gap between 1.3 ATA (soft) and 2.4 ATA (hospital) is a more-than-tenfold difference in arterial oxygen per Tibbles & Edelsberg 1996 in NEJM.
Soft-chamber clinics that claim hospital-grade outcomes are overselling.
"We don't need a medical director — the techs handle it." Any legitimate clinical HBOT program has a physician medical director. Wellness-only mild HBOT clinics may operate without one, but they should disclose this rather than dismiss the question.
"Insurance covers all our treatments." Insurance covers only the 14 FDA-approved indications. If a clinic claims insurance covers off-label uses, they are misleading you.
Off-label uses include anti-aging, long COVID, autism, and TBI for most cases. Ask for the insurance verification in writing before you start. See detailed Shamir long-COVID RCT analysis for the full Shamir-RCT methodology analysis.
"You can use your phone or wear nylon inside the chamber." Both create fire risk. Reputable clinics enforce strict rules on materials inside the chamber.
The 1997 Milan chamber fire killed 11 people. It remains the reference incident for chamber fire safety.
"We don't share inspection records or 510(k) information." Legitimate clinics share all of this on request. A clinic that resists basic documentation should not be operating on you.
Aggressive package upselling on the first visit. Reputable clinics walk you through a treatment plan after evaluation, not before. A 40-session package quoted at $15,000 to $50,000 before any clinical review is a sales tactic, not medical care.
Specific risks to understand
HBOT carries real risks that vary by chamber type and patient factors.
Middle ear barotrauma is the most common adverse event. Rates run 2% to 10% per the Camporesi 2014 review in Undersea & Hyperbaric Medicine.
Most cases resolve. Patients with ear tube issues, recent ear surgery, or a cold should disclose to the clinic.
Oxygen toxicity seizures occur at 1 to 4 per 10,000 sessions at 2.4 ATA. Risk rises above 2.8 ATA, which is why most non-emergency protocols cap there. Patients on ciprofloxacin or steroids may have higher risk.
Pulmonary barotrauma is rare but possible with untreated pneumothorax, severe COPD, or recent chest surgery. Pre-treatment chest imaging catches most cases.
Fire risk is the most serious chamber risk. Soft-chamber fires have been documented in trade publications, with the most recent widely-reported case in Michigan in 2025. Hard chamber fires are rare but have caused fatalities including the 1997 Milan incident.
Sudden visual changes can occur, particularly progressive nearsightedness in older patients across long protocols. The effect usually reverses within weeks of treatment ending.
The questions checklist
Take this list to your initial consultation:
- Is your clinic UHMS-accredited? What year?
- Who is your medical director? What is their hyperbaric training?
- What chamber make, model, and FDA 510(k) number do you use?
- Are your operating technicians CHT or CHRN certified?
- What pressure protocol will I be on, and what published evidence supports it?
- Is my condition FDA-approved or off-label?
- For off-label use, what is your honest read on the evidence?
- What does insurance cover for me?
- What is your pre-dive screening protocol?
- What is your emergency response if I have an adverse event?
- Can I see your most recent chamber inspection records?
- What fire safety protocols do you follow?
- What is the total cost, including any required add-ons?
Honest clinics will answer every question without deflection. Pushback or vague answers on any of them is the signal to look elsewhere.
Patient screening to expect
Reputable clinics screen patients before starting. Expect:
- Medical history review including ear, lung, and cardiovascular conditions
- Current medication list (some meds increase oxygen toxicity risk)
- Pre-treatment chest X-ray for pulmonary barotrauma risk
- ENT evaluation if you have ear tube dysfunction history
- Informed consent discussion of risks and FDA status
- Discussion of contraindications (untreated pneumothorax is absolute)
Clinics that skip screening are either overconfident or careless. Both should make you uncomfortable.
After your session — what to monitor
Most sessions are uneventful. But know what to watch for:
- Ear pain that doesn't resolve within 24 hours — see an ENT
- Vision changes — usually progressive nearsightedness, usually reversible
- Chest pain or shortness of breath during or after — emergency
- Seizure activity — emergency
- Fatigue or headache — common, usually resolves within hours
Any clinic that doesn't give you written discharge instructions covering these is cutting corners. Ask for them in writing before you leave the first session.
Related reading
- HBOT regulation guide: FDA, UHMS, and clinic accreditation
- UHMS facility accreditation: what it signals to patients
- HBOT contraindications: when it's genuinely dangerous
- HBOT safety profile: complications from published trials
Frequently asked questions
How do I check if a clinic is UHMS-accredited?
Search the UHMS accreditation directory by clinic name or location. The directory lists all currently accredited facilities. If a clinic claims accreditation and isn't in the directory, that's a red flag. Roughly 11% of US HBOT centers are accredited.
Does my insurance cover HBOT?
Insurance covers HBOT for the 14 FDA-approved indications under Medicare NCD 20.29. Private insurers generally follow Medicare's list. Off-label uses — anti-aging, long COVID, TBI for most cases, autism — are cash-pay only. Always get insurance coverage confirmed in writing before starting a paid program.
Is mild HBOT (soft chamber at 1.3 ATA) safe?
When operated correctly, yes — for its FDA-cleared indication of acute mountain sickness. The pressure level is lower than hospital HBOT, so risk per session is generally lower. Fire risk from electronics or improper concentrator handling remains a serious concern. Soft-chamber operators may not have CHT-certified techs or medical director oversight.
What's the most important question to ask?
"What is your chamber make, model, and FDA 510(k) clearance number, and can you confirm UHMS accreditation status?" Both answers can be verified independently before you book. A clinic that answers plainly is meeting basic transparency standards. A clinic that resists is the one to skip.
Can I do anything if a clinic mistreats me?
Yes. Report adverse events to the FDA via MedWatch. Report unethical clinic practices to your state medical board. Consult an attorney if you believe negligence caused injury. Document everything in writing — the clinic's claims, the chamber model, the staff names, and what happened during your session.
Medical disclaimer
This article is for informational purposes only and is not a substitute for professional medical advice. Hyperbaric oxygen therapy is investigational for most off-label uses discussed here. Consult your doctor before starting any HBOT protocol, especially if you have pre-existing ear, lung, or cardiovascular conditions. Always verify a clinic's UHMS accreditation, medical director credentials, and FDA-cleared scope before booking. If you experience an adverse event during or after HBOT, seek medical attention and report to the FDA.
-- The HBOT Finder Team