Was working at a major do-it-yourself store where they sold a product with copper sulphate to treat termite-infested wood. This guy comes in looking for more of the product that they warn you to wear a safety mask to spray. His face was light blue and he sermed out of breath. I was shocked when I saw him and wanted to tell him to get to a hospital. He was spraying it under his house with no mask. The product was labeled as quite dangerous. Been a long time but, am I wrong? It can reduce your oxygen intake abilty?