The little-told story of how the U.S. government poisoned alcohol during Prohibition with deadly consequences.

Rigorous enforcement had managed to slow the smuggling of alcohol from Canada and other countries. But crime syndicates responded by stealing massive quantities of industrial alcohol—used in paints and solvents, fuels and medical supplies—and redistilling it to make it potable.

Well, sort of. Industrial alcohol is basically grain alcohol with some unpleasant chemicals mixed in to render it undrinkable. The U.S. government started requiring this "denaturing" process in 1906 for manufacturers who wanted to avoid the taxes levied on potable spirits. The U.S. Treasury Department, charged with overseeing alcohol enforcement, estimated that by the mid-1920s, some 60 million gallons of industrial alcohol were stolen annually to supply the country's drinkers. In response, in 1926, President Calvin Coolidge's government decided to turn to chemistry as an enforcement tool. Some 70 denaturing formulas existed by the 1920s. Most simply added poisonous methyl alcohol into the mix. Others used bitter-tasting compounds that were less lethal, designed to make the alcohol taste so awful that it became undrinkable.

To sell the stolen industrial alcohol, the liquor syndicates employed chemists to "renature" the products, returning them to a drinkable state. The bootleggers paid their chemists a lot more than the government did, and they excelled at their job. Stolen and redistilled alcohol became the primary source of liquor in the country. So federal officials ordered manufacturers to make their products far more deadly.

By mid-1927, the new denaturing formulas included some notable poisons—kerosene and brucine (a plant alkaloid closely related to strychnine), gasoline, benzene, cadmium, iodine, zinc, mercury salts, nicotine, ether, formaldehyde, chloroform, camphor, carbolic acid, quinine, and acetone. The Treasury Department also demanded more methyl alcohol be added—up to 10 percent of total product. It was the last that proved most deadly.

The results were immediate, starting with that horrific holiday body count in the closing days of 1926. Public health officials responded with shock. "The government knows it is not stopping drinking by putting poison in alcohol," New York City medical examiner Charles Norris said at a hastily organized press conference. "[Y]et it continues its poisoning processes, heedless of the fact that people determined to drink are daily absorbing that poison. Knowing this to be true, the United States government must be charged with the moral responsibility for the deaths that poisoned liquor causes, although it cannot be held legally responsible."

His department issued warnings to citizens, detailing the dangers in whiskey circulating in the city: "[P]ractically all the liquor that is sold in New York today is toxic," read one 1928 alert. He publicized every death by alcohol poisoning. He assigned his toxicologist, Alexander Gettler, to analyze confiscated whiskey for poisons—that long list of toxic materials I cited came in part from studies done by the New York City medical examiner's office.

Norris also condemned the federal program for its disproportionate effect on the country's poorest residents. Wealthy people, he pointed out, could afford the best whiskey available. Most of those sickened and dying were those "who cannot afford expensive protection and deal in low grade stuff."

And the numbers were not trivial. In 1926, in New York City, 1,200 were sickened by poisonous alcohol; 400 died. The following year, deaths climbed to 700. These numbers were repeated in cities around the country as public-health officials nationwide joined in the angry clamor. Furious anti-Prohibition legislators pushed for a halt in the use of lethal chemistry. "Only one possessing the instincts of a wild beast would desire to kill or make blind the man who takes a drink of liquor, even if he purchased it from one violating the Prohibition statutes," proclaimed Sen. James Reed of Missouri.

Officially, the special denaturing program ended only once the 18^th Amendment was repealed in December 1933. But the chemist's war itself faded away before then. Slowly, government officials quit talking about it. And when Prohibition ended and good grain whiskey reappeared, it was almost as if the craziness of Prohibition—and the poisonous measures taken to enforce it—had never quite happened.

Correction, Feb. 22, 2010: The article originally and incorrectly said that the 18^th Amendment banned the sale and consumption of alcohol. It banned the manufacture, sale, or transportation of alcohol, not consumption. (Return  to the corrected sentence.)