The purchasing of unofficial identification tags goes back to the Civil War. In the Navy, official identification tags, nicknamed "dog tags," go back to World War I. They were first prescribed by Secretary of the Navy Josephus Daniels in General Order No. 294 of 12 May 1917. These first tags were oval, of Monel metal (a patented corrosion-resistant alloy of nickel and copper, with small amounts of iron and manganese), 1.25 inches wide and 1.5 inches long. Perforated at one end, a single tag was to be worn around the neck on Monel wire "encased in a cotton sleeve." One side of the tag bore an etched print of the right index finger. The other side was stamped "U.S.N." and etched with the individual's personal information. Officers' tags bore initials and surname; rank; and date of appointment, in numerals denoting month, day and year (e.g., 1.5.16). Enlisted tags bore initials and surname, with date of enlistment and date of birth, in numerals as on officers' tags.
The tags were, apparently, not used in the years after World War I. Navy regulations, and the Bureau of Naval Personnel Manual, 1925, provided that, "in time of war or other emergency, or when directed by competent authority, individual identification tags shall be prepared and worn by all persons in the naval service," suspended from the neck or from the wrist on cotton-sleeved Monel wire. Monel-metal chain could be used at the individual's expense.
With the onset of World War II, the Navy reinstated use of the tags. Bureau of Navigation Circular Letter 57-41, dated May 13, 1941, directed "that each officer and enlisted man of the Navy and Naval Reserve be issued an identification tag". These continued to be made of Monel metal, 1.25 by 1.5 inches, but perforated at each end. The face of each tag was to bear the individual's name; officer rank or enlisted service number; blood type; if vaccinated for tetanus, the letter "T" with date in numerals (e.g., 8/40); and service (USN, USMC, USNR, USMCR). A right index fingerprint was etched on the reverse. Bureau of Navigation Circular Letter 152.41, dated 16 December 1941, directed the monel identification tags be prepared and furnished to the officers and enlisted men of the Coast Guard.
As World War II went on, Bureau of Naval Personnel Circular Letter 83-43, (later codified in Navy regulations and the Bureau of Naval Personnel Manual) prescribed the use of a second tag, individually suspended by a short length of chain so that one tag could be removed "on death or capture, leaving the other in place." Naval Supply Depots at Bayonne, NJ, and Oakland, CA, served as the sources for fulfilling fleet requirements for tags and graphotype machine.
Dimensions remained the same, but the tag was to be of "corrosion-resisting material" - 17 percent chromed steel. (Monel metal was no longer specified), perforated at each end, and the etched fingerprint was omitted. Markings consisted of name; officer file number, or enlisted service number; blood type; date of tetanus inoculation; service; and religion, if desired by the service member: Catholic (C), Protestant (P), or "Hebrew" (H). When a service member was buried, ashore or at sea, one tag was to be left with the body and the other sent to BuPers "as soon as practicable under the circumstances."
Post-World War II tags were worn on a bead chain, with attached short loop for the second tag. They bore name (surname, followed by initials); service number; service; blood type; and religion, if desired by the individual.
Sources of Information:
Braddock, Paul F. "Armed Forces Identification Tags." Military Collector & Historian 24, no.4 (Winter 1972): 112-14.
Bureau of Naval Personnel Manual, 1942 & 1945.
Sources of copies of dog tags:
Copies of the Post-World War II dog tags with three lines of 15 characters each, as well as silencers that fit around individual tags to keep them from clinking are sold by the Gift Shop, National Museum of American History, 14th and Constitution Avenue, Washington, DC 20560.
Many firms also make tags of this type. A search of classified directories and military/veterans magazines should identify such producers.