You always know which way the wind is blowing; Sulfur & Chlorine are the dominant smells around a pulp paper mill. The mill in Wallula, WA., near Pasco, was quite pungent last time I drove by. The use of chlorine in the bleaching process, is the reason I would be issued an emergency breathing apparatus whenever I delivered to Simpson Paper. One over zealous guard initially refused me admittance due to my moustache. "It might interfere with your breathing apparatus in an emergency ", was his reason. Once I pointed out that any release of chlorine would probably kill me before I could put it on, he & his boss relented.