I bought one of the common red O2 cylinders from Home Depot and I noticed a warning on the label. It reads, "Warning: This container and byproducts of the combustion of its contents contain chemicals known to the state of California to cause cancer, birth defects or other reproductive harm." I read this as strictly talking about the container but am I overlooking a safety issue regarding any impurities or chemicals mixed along with the oxygen itself? I have never heard of any dangers in using these before but was curious about it. -thanks.