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.
Yet another answer Copper is sometimes used for covering roofs because it is much less expensive than gold, which is the very best metal to use against erosion! However, if it is situated in a corrosive atmosphere, over several years copper turns a light-green colour due to surface oxidation.et another answer Copper is sometimes used for covering roofs because it is much less expensive than gold, which is the very best metal to use against erosion! However, if it is situated in a corrosive atmosphere, over several years copper turns a light-green colour due to surface oxidation.