My apartment in central Denver is charming, slightly overpriced, and within walking distance of shops, parks, and... chemical facilities. I wasn't expecting that. I'm also not unique. Over 100 million Americans live around dangerous chemical plants and refineries. We live, work, play, and go to school in "vulnerability zones": areas that could be in danger were a chemical company to suffer an accident, leak, or explosion. There have been over 350 preventable chemical accidents in just the past two years. That's really scary, but there's good news. Better chemicals and processes that could...