Mich. Comp. Laws § 752.256: Liquid fuels, lubricating oils; labeling of distributing equipment.

Sec. 6.

There shall be firmly attached to or painted on containers, tanks, pumps or other distributing equipment at or near the point from which liquid fuels, lubricating oils or similar products are drawn or poured out for sale or delivery, a sign or label consisting of the word or words in letters not less than 1 inch in height comprising the brand or trade name of such liquid fuels, lubricating oils or similar products; and if any of such liquid fuels, lubricating oils or similar products shall have no brand or trade name the sign or label shall consist of the words, in letters not less than 3 inches high, "Gasoline, No Brand", or "Lubricating Oil, No Brand", or words of similar effect in the case of other products.