>So the real question is, how long does it take for the Zinc Oxide to be depleted, how much does it cost to replace, and how hard is it to replace? …and don't

>So the real question is, how long does it take for the Zinc Oxide to be depleted, how much does it cost to replace, and how hard is it to replace? …and don't forget "how poisonous is the stuff you're dumping out?" (straight into the environment, your water/food source)