Adulteration of [or] blending of products sold under same

name. No person shall knowingly expose for sale, offer for sale or sell any petroleum product as a[n] unadulterated product of a manufacturer or distributor or as the unadulterated product of any other manufacturer or distributor if it has been mixed, blended, compounded or adulterated with a petroleum product of the same manufacturer or distributor that is of a different quality or character from the quality or character of the other petroleum products. Nothing in this section shall prevent the lawful owner of a petroleum product from applying his own trademark, trade name or symbol to any product or material.