Quote:
In the early 1860's, when oil production began, there was no standard container for oil, so oil and petroleum products were stored and transported in barrels of all different shapes and sizes (beer barrels, fish barrels, molasses barrels, turpentine barrels, etc.). By the early 1870's, the 42-gallon barrel had been adopted as the standard for oil trade. This was 2 gallons per barrel more than the 40-gallon standard used by many other industries at the time. The extra 2 gallons was to allow for evaporation and leaking during tranport (most barrels were made of wood). Standard Oil began manufacturing 42 gallon barrels that were blue to be used for transporting petroleum. The use of a blue barrel, abbreviated "bbl," guaranteed a buyer that this was a 42-gallon barrel.
EDIT: This will be difficult, as it is quite easy to find citations for "bbl oil" from before 1850 using google books, the first I found was on p. 239 of a book called "Railway engines and cars" from 1832. So the blue barrel legend can be firmly laid to rest in peas.
Ha! The doubled b in bbl is likely an outmoded typographical convention - as in book citation p437, and also pp495-500. I like such archaisms but agree it's a bit confusing and inconsistent with other conventions - eg we don't talk of $5 bbn to mean five billions.
Ahh, wikipedia knows: The "b" may have been doubled originally to indicate the plural (1 bl, 2 bbl), or possibly it was doubled to eliminate any confusion with bl as a symbol for the bale. Some sources claim that "bbl" originated as a symbol for "blue barrels" delivered by Standard Oil in its early days; this is probably incorrect because there are citations for the symbol at least as early as the late 1700s, long before Standard Oil was founded.