ucfdiver
Contributor
It's more tricky than you describe. I took a Naui course where I went on a deco dive using trimix when I was not certified for either. Many combine Advanced Nitrox, Decompression Procedures, and Trimix into one course.If this is what the investigation is regarding, it's not that he taught Trimix to a diver that simply lacked Full Cave training. Full Cave isn't a pre-req for ANY deco training. However, when certs specifically limit depth and explicitly state "No Decompression".....and someone takes you to them anyway, it's a violation of standards.
My understanding is that you're allowed to take a student one level beyond what they're certified to dive. An OW diver can be taken to a Cavern. A Cavern diver can do an Intro dive. An Intro diver can do an Apprentice dive. An Apprentice dive can do a Full Cave dive. OR, you take someone with no deco and do an AN/DP dive with them. However, taking an Intro diver well beyond those limits while exceeding other limits IS an issue. In the overhead, you must have Full Cave to be doing decompression dives.
In this case they went up a cave level and up a mixed gas level. It is my understanding that when guiding up a level a waiver is needed and it's assumed that the same predive briefing and rules as the first class dives are followed.