It could be argued that technical diving history started with the development of the first rebreathing set in 1879. Other possible starting points are the development of oxygen decompression or the use of mixed gas diving sets.
An appropriate beginning is 1970 when NOAA, a civilian component of the US Government, launched the use of oxygen/nitrogen mixtures with more oxygen than the 20-21 per cent in air. This has been termed nitrox or enriched-air diving, and NOAA did this to increase the productivity of their divers. By 1986 Rutkowski, who was associated with NOAA, had launched an association to promote and regulate the amateur use of nitrox.
Technical diving history starts when the initial response from 'the establishment' was largely to condemn and ban the use of amateur nitrox diving because of the perceived risks. In less than 10 years this situation had been reversed, and nitrox diving was accepted and taught by most of the diving instruction organizations.
This reversal had several causes. Most important, the customers recognized that nitrox diving had benefits for them. The opposition of the establishment was shown to be largely unjustified. Also, some diving opinion makers realized that the nitrox technical diving enthusiasts needed guidance, not condemnation, and provided it. Reports appeared with findings that supported the use of nitrox diving. Ornhagen and Hamilton reported a rigorous set of Swedish trials, and the favourable results of a US Navy study, including an input from divers who had been trained in the technique and asked to evaluate it for US Navy use.
The use of mixed gas diving with changes in mixtures can be traced back at least to the dives of Keller in the 1960s, these included a 307-metre (1000-feet) dive that became a diving history moment. Zetterstrom could also be considered a technical diver with his pioneering hydrogen mixture dives. Since about 1980 dives with closed- and open- circuit systems have pushed the depth and time boundaries, though not always safely. In 1994, Exley became one of several leading proponents to die during a dive.
One of the more impressive set of technical dives was the expedition to the Lusitania, where 120 dives were made for a total bottom time of about 40 hours. These dives were to depths of up to 93 metres in the highly tidal North Atlantic. A couple of years later divers reached the wreck of the Britannic in 119 metres of water (technical diving). Both these series of dives were conducted without injury - feats that could be matched by few navies! Deep diving companies could dive these wrecks safely with saturation methods, but they would need a large ship and support staff rather than a small launch.
It is noted that there was criticism of the Lusitania dives from within the technical diving fraternity. The main critic came to technical diving from commercial diving, and seemed to not accept that the expedition was self-funded and could not afford the back-up he would have liked.
Because of the greater risks, the more complex forms of technical diving have attracted condemnation and this has slowed the development of the sport. To some extent it has been the province of the thrill-seeker, but is also being used by workers with a need to reach greater depths. Many of the leading diving experts are now accepting the use of rebreathing sets for technical diving.
Often technical diving victims died doing something that they would consider careless if done by another. Two Australian leaders in the field probably died by choosing the wrong gas mixture from the range they carried.