4. carbon dioxide buildup 5. oxygen sensor failure 6. deep tissue isobaric counterdiffusion (ICD) 7. high pressure nervous syndrome (HPNS) 8. exhausting your carbon dioxide scrubber 9. carbon dioxide channeling from a poorly packed scrubber 10. carbon buildup causing an spark leading to an oxygen fire. underwater. 11. flooding of breathing loop or circuitry 12. water mixing with the scrubbing agent to produce a toxic caustic soda that will give you chemical burns on your mouth, airway, and lungs 13. plain old decompression sickness 9 — ChaosConf 2018 @rondoftw