My 20 gallon air compressor blew up this past afternoon. The tank blew apart. This was an old, 40+, 220volt twin cylinder 20 gal. I had it sitting outside the basement door when it was running. I was on the other side of the house when it blew up. It sounded like a stick of dynamite. The whole house shook. Parts of it damaged 2 different areas of my gutters, 16 feet high. The twin cylinder part went thru the basement door window and landed in my canoe. It hit my gunwale and messed it up. I didn't find any more damage to it. The explosion blew out another basement window. There is damage to the siding where other pieces hit the house. Right after it happened my neighbor came carrying the end of my compressor tank, it blew that end piece over 200 feet into his yard. Check your pop off safety valves. If in doubt of your tank condition, get rid of it. I'm glad I wasn't on that end of the house.