A Hunter-Gatherer's Guide to the 21st Century: Evolution and the Challenges of Modern Life

by Heather E. Heying

Before propane and natural gas are piped into your home, or delivered to a tank outside of it, they have tert-Butyl mercaptan added to them.

Our detectors for CO2 are so ancient and deeply wired that even people with brain damage to the amygdala, such that they never panic under other fear-inducing circumstances, find themselves triggered into panic by high concentrations of CO2.