New Zealand’s Gas Cylinder Regulations: Hot Air?

By Franz Ombler. Image by Sami Paakkarinen

Apparently we can’t use gas mixes with helium, or with oxygen content less than 21% or higher than 40%. Many of the cylinders our EU and US counterparts use in their technical diving can’t be affordably imported into New Zealand and specific cylinder models have limited permitted uses under our parochial, archane regulations, such as for ‘breathing air’, thereby limiting unnecessarily what we can put in them.

New Zealand’s regulations are overly prescriptive, dangerously strict and out of touch with private and industry practice both here in Aotearoa and internationally.

Most of us start out diving using air and the main decision about a tank purchase is whether you go for aluminium or steel, and if steel, 12L or 15L.

But technical diving is becoming more and more popular. People are diving deeper with twin tank rigs, side mount and rebreathers, and for those diving down towards 100m it’s not unusual to carry six tanks in a variety of sizes and with a different gas in each.

If we’re diving below about 30m, we add helium to reduce the nitrogen content so that we’re less likely to suffer the effects of nitrogen narcosis. If we’re diving deeper than 66m we have to add helium to reduce the O2 content of our mix so we don’t convulse from oxygen toxicity. Once we’re down at 100m we’re mainly breathing helium.

On the way back up from our dives we need gases with progressively more oxygen to help off-gas the nitrogen and helium with which our bodies are now saturated. Once we’re back to 20m we might switch to 50% oxygen and above 6m we might be on pure oxygen for a time.

Not surprisingly, a key part of technical diver training is gas planning and almost everything we learn is about safety and reacting well in case of difficulties. But what we’re doing is illegal!

Yep, no kidding. The New Zealand Government seems to think it knows all about diving and in the name of safety they regulate what tanks we can use and what gases we can put in them.

Many in the industry are used to not getting government officials to see sense so in the past they simply ignored the rules. Others stayed mum because they feared large fines (or worse) should they admit openly they are ignoring the regulations. Some are just too busy trying to run a business to give it much thought, and many divers don’t know the regulations exist.

Professional dive operators who are best trained to help us do this safely are now subject to health and safety audits and unwilling to risk their business by providing us with the gas and equipment we need to conduct our dives safely.

Dives we can do abroad, like the USS Atlanta dive on page 10, are simply not possible here performed under the New Zealand regulations, and a consequence is our industry is beginning to lose out on technical diving tourists who cannot be provided with the gear and gases they need.

So what about those old aluminium cylinders blowing people’s limbs off here and overseas? If we were to trust authorities overseas wouldn’t this risk get worse?

The joke is while we’re not able to use the most perfectly safe modern cylinders, we’re still legally allowed to fill these dangerous old cylinders.[1] It’s with these dangerous old cylinders that we need stronger regulations!

If it weren’t for the commendable boldness of the New Zealand Underwater Association (NZUA) in January forbidding its members to fill these cylinders, as well as getting agreement from their members to go along with their edict, they would still be being filled today. Some still are. What will it take for the government to get its priorities right and operate a banned cylinders list based on advice from organisations like the NZUA?

Overhauling the regulations should be easy! The government needs to learn to trust the quality assurance systems of trusted jurisdictions like the EU and the US, and for the most part, trust our diving industry, training agencies and divers who are intimately concerned for each other’s safety.

Where the government needs to step in, it should step in boldly based on sound advice.

[1] According to the regulations, manufacturers’ recommendations must be followed when filling cylinders. In 2004, Luxfer recommended these cylinders should only be filled behind a blast screen, which most fillers do not have, so technically, most of these cylinders have not been legally filled in NZ since 2004 though no one knew, WorkSafe included.

The issue of cylinder importation was the subject of a petition circulated over summer and has been referred to the Government Administration Select Committee to consider. The issue of gases, among other things, was raised by divers in response to consultation by the Environmental Protection Agency on a proposed notice relating to private filling of scuba cylinders. You can dive deeper into these topics at and

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