The Surgeon General convened a parley in May 1925 to hash out the question. On one side were the industrial hygiene people, an impressive group that included Yandell Henderson of Yale University, who stated that “leaded gasoline will be in nearly universal use and large numbers of cars will have been sold ... before the public and the government awaken to the situation.” He argued the precautionary principle: that it was up to industry to prove that coating American roads and cities with lead powder was not the bad idea that it sounded like. On the other side were Kettering and his supporters, contending that, in the words of one Standard Oil executive, “Leaded gasoline is a gift of God ... Because some animals die and some do not die in some experiments, shall we give this thing up? It must not be fears, but facts that we are guided by.”