Ozone stratosphere was discovered to be declining, mostly because of increasing concentrations of chlorofluorocarbons (CFC) and similar chlorinated and brominated organic molecules. The concern over the health effects of the decline led to the 1987 Montreal Protocol, the ban on the production of many ozone depleting chemicals and in the first and second decade of the 21st Century the beginning of the recovery of stratospheric ozone concentrations. Ozone in the ozone layer filters out sunlight wavelengths from about 200 nm UV rays to 315 nm, with ozone peak absorption at about 250 nm. This ozone UV absorption is important to life,
Day of the Animals claiming that chemical waste released into the atmosphere has dangerously depleted the ozone layer, which protects all life from the sun's radiation. On the mountain, the hikers stumble upon a camp where a fire is burning and coffee cups are ready to be filled, but nobody is around. Steve says the campers will soon be back. He leads the hikers to a nearby spot to bed down for the night. They build a fire, and while Daniel pulls Steve aside to tell him that something strange is going on in the woods. Steve asks him not to say anything to