The Early Days of Technical Trimix Diving

The use of trimix, that is a breathing mix of oxygen, helium and nitrogen has become the standard for dives beyond 30-50m/100-165 ft, depending on who you dive with. However, things were much different when mixed gas technology was just emerging. Here is an in depth look at the early days of what was then called “special mix” diving including an explanation of special mix tables by Dr. RW Bill Hamilton, a report on the first 1500 trimix dives by then aquaCORPS chief Michael Menduno, and a selection of Key West Diver Consortium tables for dives to 76 m/250 ft. From the aquaCORPS archives.