gasoline blend for a few months to increase octane and stop engine knock. In 1923, French assembly passes the Carburant National law requiring gasoline importers to buy alcohol for 10% blends from the State Alcohol Service. The law has a far-reaching impact as many other nations, especially Brazil and other sugar-cane growing countries, were influenced to enact similar laws based on the French and German programs. By the mid-1920s, ethyl alcohol is blended with gasoline in every industrialized nation, and some blends are showing up as experiments in the United States, but the market is dominated by leaded gasoline. In October of 1924, a catastrophic miscalculation in the production of leaded gasoline causes at least 17 refinery deaths and many dozens of permanently debilitating injuries. GM and Standard very nearly abandon leaded gasoline, but decide to defend it, claiming (contrary to their own prior published research) that ""So far as science knows at the present time, tetraethyl lead is the only material available which can bring about these [antiknock] results." In 1925, Henry Ford tells The New York Times that ethyl alcohol is "the fuel of the future" which "is going to come from fruit like that sumach out by the road, or from apples, weeds, sawdust -- almost anything. There is fuel in every bit of vegetable matter that can be fermented. There's enough alcohol in one year's yield of an acre of potatoes to drive the machinery necessary to cultivate the fields for a hundred years." In 1926, US Public Health Service allows leaded gasoline to return to the market. In 1928 Harry Ricardo, National Distillers Co. and Shell Oil introduce an alcohol fuel blend in the United Kingdom called "Cleveland Discol." The ethanol blend is a popular unleaded gasoline brand and is sold through 1968. In August 1930, the German government required all gasoline importers to buy 2.5% of the volume of their imports from the German Alcohol Monopoly, and the ratio was increased to 6% and then 10% by 1932. Estimates of alcohol used in 1932 vary from 44 million liters to about 175 million liters. Some 36,000 small farm alcohol stills, owned by the monopoly, were in operation at this time. By 1938, Germany was producing about 267 million liters of ethanol, about two thirds from potatoes and the rest from grain, wood sulfite liquors and beets. Some 89 million liters of methanol were produced