What do you mean the exchanges dont and shouldnt get involved in measurement standards  Of course its not up to an exchange to DEFINE a standard but since the NYMEX defines so many technical aspects of oil trade when its traded where its delivered quality aspects sulphur etc its strange that they dont define the quantum or unit of trade in terms of STANDARD UNITS  such as by weight lbs or kg or by volume cubic feet yards or meters or gallons or liters  Its a CONTRACT after all and a good contract leaves NOTHING unexplained or uncertain