Dive Health & Safety
Carbon monoxide in scuba tanks: how contamination happens and how to check
Carbon monoxide (CO) can contaminate scuba air when a compressor draws in exhaust or its filters are worn. It's odourless, colourless and tasteless, and its symptoms — headache, dizziness, nausea, confusion — look like many other problems, so you can't rely on them. Divers Alert Network recommends smelling and tasting your gas, testing it with a CO analyser, and analysing oxygen.
By 71 Guardians · Published 19 Oct 2026
How does carbon monoxide get into a tank?
- As a by-product of the compression process itself.
- A compressor intake near combustion sources — vehicle exhaust, smoke.
- Filters that haven't been replaced when they should be.
What are the symptoms?
Headache, dizziness, weakness, nausea, vomiting, shortness of breath, impaired judgement, confusion and unconsciousness. Because they're vague and look like other dive-related problems, symptoms alone can't diagnose contamination.
How can I check my gas?
- Don't dive with gas that smells or tastes unusual — though no smell doesn't mean no CO.
- Use a personal portable CO analyser, in addition to any monitoring at the fill station.
- Analyse the oxygen content of every cylinder.
What if I suspect contamination?
Get medical evaluation and, if possible, have the gas analysed. Tell the fill station. If an incident may be linked to contaminated gas, keep the tank and contact DAN.
Frequently asked questions
Can I smell carbon monoxide?
No — it's odourless, colourless and tasteless.
Do I need my own CO analyser?
DAN recommends personal portable CO analysers as an extra check.
Questions before you dive with us?
Message our team on WhatsApp — we're divers in Hurghada and happy to help.
Chat with us on WhatsAppSources
- Breathing Gas Safety Basics — Divers Alert Network (DAN)