When the gasoline job was finished, our division, which was making refrigerators and air conditioning units, asked Thomas Midgley, head of the Organic Chemistry Department to take up the work on refrigerants. A set of ideal specifications was written. The new gas must be non-inflammable. It must be non-toxic. It must be non-irritating, and it should not be expensive. But, studying all the available scientific tables and data, it was found that only a few things could even be considered, and there were some objections to each one.

     There was a bare possibility that some could be combined so that the bad qualities would neutralize each other.

     Looking at the tables, one of the most promising group of chemicals contained Fluorine, but Fluorine had a bad reputation - even to a high school chemist. Midgley said of the work, "We plotted the boiling points, worked slide rules, brushed away eraser dirt and pencil shavings and did all the other formalities that take the place of tea leaves and crystal balls in the life of a scientific fortune teller."

     After this had gone on for a long time, the search focused on one compound which, for the sake of simplicity, they called F-12.