On June 28, 1943, Bryon Price, director of the United States Office of Censorship (OoC) and former executive news editor of the Associated Press, sent out a confidential note to 2,000 daily newspapers and 11,000 weeklies as well as all radio stations in the U.S. The note requested that editors prevent any articles or broadcasts from mentioning:
Production or utilization of atom smashing, atomic energy, atomic fission, atomic splitting, or any of their equivalents.
The use for military purposes of radium or radioactive materials, heavy water, high voltage discharge equipment, cyclotrons.
The following elements or any of their compounds: polonium, uranium, ytterbium, hafnium, protactinium, radium, rhenium, thorium, deuterium.