Before 1930, refrigerators were not only bulky and expensive but extremely dangerous. Chemicals used as refrigerants—ammonia, methyl chloride, and sulfur dioxide—were not only toxic but highly combustible. In 1929 a leak in a methyl chloride refrigeration system caused an explosion that killed more than 100 people in a Cleveland hospital. It was no wonder that consumers preferred their old iceboxes. That would all change in 1930 with the invention of Freon by a General Motors researcher.
One of the most versatile and familiar products of American chemical engineering, Teflon, was discovered by accident. There are many such tales to be found in the history of industrial chemistry, from vulcanized rubber to saccharin to Post-Its, all of which were stumbled upon by researchers looking for other things. So common, in fact, are unplanned discoveries of this sort that one might expect would-be inventors to simply mix random chemicals all day long until they come up with something valuable.