How Long Does Air In Scuba Tank Last?

by Robert Bauer
(La Feria, TX USA)

I bought a new scuba tank 12 years ago and never used it. The tank is now 12 years old. Is the air still safe to use?

Hi Robert,

Thanks for getting in touch. Whether the air in your tank is good or not is actually now a secondary question. The tank in question is long past due for inspections.

All tanks, whether steel or aluminum, have to pass a hydrostatic test every 5 years and a visual inspection every year. Obviously this has not been done.

Since the tank has not been inspected in so long, I would definitely get it tested before using it. Corrosion could have started inside the tank which could affect the oxygen levels.

While there may be nothing wrong with it, I think it is better to be safe than sorry.

Let us know how it goes.

Dianne

Comments for How Long Does Air In Scuba Tank Last?

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Rating
starstarstarstarstar 		Bad air
by: Aquanaut

Don’t know about you all but I had a couple AL Luxfer 80s that was full for 4 years. I went to clean the bottom of my boat and just about drowned. After about 20 minutes I came to the surface gasping for air. I thought it was the regulators, had them tested but they were OK. There was no other reason. I am (was) a trail hiker too. Not any more.
At first I started having trouble getting my breath when I went to bed. I would have to take deep breaths for awhile. That’s past now but I still run of of breath just shoveling dirt. It’s been like this for 4-1/2 years now.

If you have old air, drain it and get it refilled and/or tested first. Don’t take the chance!!! Btw I’ve been (had been) diving since 1969.
Rating
starstarstarstarstar 		It depends
by: Chris

If the tank is aluminum then maybe it's OK (see below). If it's a steel tank then it will kill you. The reason is over a period of time the O2 in the tanks air will break it's molecular bond and one Oxygen element from the O2 will bond to the steel. The resulting reaction turns the free Oxygen element into O1. That remaining O1 element will be free to bond with any free carbon in the cylinder's air or from the tank itself to form CO. Also know as Carbon Monoxide. At depth, that CO will render you unconscious. Worse, no buddy breathing from fresh air will save you. The only fix for CO poisoning is pure Oxygen if administered soon enough. Unlikely while diving. Now for the aluminum maybe. Over a period of time aluminum reacts with the steel valve in a process known as galvanic corrosion. It occurs because dissimilar metals and alloys have different electrode potentials. This process, plus a tank stored at full pressure for a long period of time, will weaken the tanks valve seat (tanks threads) which could lead to failure. In fact it's a common failure point for aluminum tanks that are very old and well used. The bottom line, just have all outdated tanks hydro static tested before use, then you don't have to worry about it and you can enjoy your dive.
Rating
starstarstarstarstar 		How long does the air last? (aged tank)
by: Musikman1

I'm curious about this also. I just was cleaning out my storage room at home and ran into four Luxfer AL80 tanks, probably been used for less than a dozen dives. All four are loaded (3000#) with EAN36. I'm also wondering if the air is safe, filled in April, 2008!

Musikman1
Rating
starstarstarstar 		old air
by: Anonymous

had al 80 tank 5 years used it tasted of aluminum never got sick
Rating
starstarstarstarstar 		Clean oxygen?
by: Anonymous

I read the posts. Nobody commented if the air is breathable after one year. Not everyone has the luxury of being near a dive shop. I need to find some $300 maui jims in 20 feet of water. My steel tank has 2800 psi. I havent had it tested in 3 years. I beleive that is the last time it was tested. What I am gleaning is if the tank id bad, the oxygen would be used up. But nobody said what is left is poisonous or unbreathable. Therefore, since I am in fairly shallow water, i will give it a whirl. Will repost if I survive.
Rating
starstarstarstarstar 		why risk it
by: Anonymous

for the cost to have it filled why would you even take a chance that's like saying I had a sandwich in the fridge for 3weeks is it still good who cares not worth the risk
Rating
starstarstarstarstar 		It's safe.
by: Michael Ferrarone

I just conducted two separate dives looking for two iPhones that fell overboard on a fishing excursion. The first tank was filled / uninspected since 1983, and the second since 1971. That air has been in there for over 41 years and it was just fine. I trashed both tanks afterwards because they aren't safe. The dives were in 25 ft of freshwater so the pressure wasn't great enough for me to be concerned. I'd never have used them for a dive at any real depth though.
Rating
starstarstarstarstar 		Does anyone know?
by: Leonard

I'd be interested in the answer to this as well. Tanks are supposed to be visually inspected every year, however, so I would think it unwise to use air older than that. As someone else mentioned, corrosion could have set in and affected oxygen levels. Enough to make the air dangerous to use? I don't know. Hopefully someone who does will answer.
Rating
starstarstarstarstar 		Does the air go bad?
by: Rob

Okay this question has been here awhile. If the air was properly installed the tank was in good condition and there is no corrosion, then would there be anything wrong with the air?

Just curious because I have a tank 5 years old, I moved and haven't gotten to use it. So I want to give it a whirl.

Is it safe?
Rating
starstarstarstarstar 		Does the air go bad?
by: Rob

Okay this question has been here awhile. If the air was properly installed the tank was in good condition and there is no corrosion, then would there be anything wrong with the air?

Just curious because I have a tank 5 years old, I moved and haven't got to use it. So I want to give it a whirl.

Is it safe?

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