Why do oxygen tanks have an expiration date?

Answer 1

oxygen tanks expire because they are to be subjected to pressure test once every 5 years by a licensed pressure testing company. some companies would require their oxygen bottles to be refilled every three years. meaning your oxygen bottle is valid for three years from the date the pressure test was made, then you will refill the bottle and then the oxygen content will expire in two years, just in time for the next pressure test.