Potential Rocket

I was re-arranging and cleaning my shed, I have one of the SCBA's from Bob's fire truck, I knew it had air in it, but I did not know it was FULL with 2000 psi of compressed air in it. It had been like this for 5+ YEARS sitting in my shed being heated and cooled every day. I am surprised it didn't leak or rupture in that time. If I had accidentally broke the valve off, it would have shot around in my shop like a rocket.

I emptied it, it took 15 minutes.