Contamination of divers air supply
An incident occurred on a DSV where a diver’s air supply became contaminated with fumes from an overheated electrical compound. This caused the diver to fall unconscious in the water. Although he was recovered to the surface and resuscitated, the incident could have been fatal.
The investigation revealed that the diver’s primary air supply was taken directly from a high pressure (HP) bank which was being continually charged during the diving operations. The HP compressor used to charge the supply was fitted with an electric dehumidifier which had been left switched on for over 48 hours. The electrical components in the dehumidifier subsequently overheated and discharged noxious gas, which contaminated the supply.
The contractor has carried out the following actions:
- diving air supply on-line to the diver is no longer supplied from a HP bank being charged
- all HP supplies are analysed before being put on-line
- the electrical power supply to the HP compressor dehumidifier has been fitted with a time switch to prevent it being accidentally left on for extended periods and overheating
Safety Event
Published: 1 March 1998
Download: 
IMCA SF 02/98
IMCA Safety Flashes
Submit a Report
IMCA Safety Flashes summarise key safety matters and incidents, allowing lessons to be more easily learnt for the benefit of all. The effectiveness of the IMCA Safety Flash system depends on Members sharing information and so avoiding repeat incidents. Please consider adding safetyreports@imca-int.com to your internal distribution list for safety alerts or manually submitting information on incidents you consider may be relevant. All information is anonymised or sanitised, as appropriate.
IMCA’s store terms and conditions (https://www.imca-int.com/legal-notices/terms/) apply to all downloads from IMCA’s website, including this document.
IMCA makes every effort to ensure the accuracy and reliability of the data contained in the documents it publishes, but IMCA shall not be liable for any guidance and/or recommendation and/or statement herein contained. The information contained in this document does not fulfil or replace any individual’s or Member's legal, regulatory or other duties or obligations in respect of their operations. Individuals and Members remain solely responsible for the safe, lawful and proper conduct of their operations.