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.
Iron in its reduced state is green in color and the presence of reduced iron in the stool results in a green color. The iron ions in the digestive system shifts the electrolyte imbalance in the lumen and results in an osmotic pull of water into the lumen. Diarrhea is a consequence of this osmosis.