On September 7, 2009, scientists working for the Chemical Abstract Service (which assigns identification numbers to all new chemicals) entered the 50-millionth chemical substance into their Registry. Chemist and industrial hygienist Monona Rossol, President and Founder of Arts, Crafts & Theater Safety, takes a look at what all these new substances are, where they are coming from, and how they affect our health. And she'll take listener calls!