This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use.
Both metal and copper oxidize when exposed to oxygen and this is a natural process. Copper that is exposed to the outside environment is more likely to turn green and that is why copper vases and decorative pieces in gardens are often green.
Reaction of oxygen with air. Oxygen gas does not react with itself or nitrogen under normal conditions. However the effect of ultraviolet light upon oxygen gas is to form the blue gas ozone, O 3, the second allotrope of oxygen. Another way to make ozone is by passing a silent electric discharge through oxygen gas.