Launching a multi-pronged attack on caffeine-infused alcohol drinks, both the Federal Trade Commission and the Food and Drug Administration sent warning letters to four companies that market the drinks suggesting that the beverages “present unusual risks to health and safety” and that the caffeine used in the products is an “unsafe food additive.”

The companies – Charge Beverages Corp., New Century Brewing Co., Phusion Projects, and United Brands Co. – are marketing their products in violation of the Food, Drug, and Cosmetic Act because the caffeine is an unsafe food additive that “may result in adverse behavioral outcomes because the caffeine is likely to counteract some, but not all, of the adverse effects of alcohol,” according to the FDA letters.

The FDA performed a scientific review, which did not find support for the companies’ claims that the addition of caffeine to alcoholic beverages meets the legal standard of “generally recognized as safe,” the agency said.

In a statement, Dr. Joshua M. Sharfstein, the FDA’s Principal Deputy Commissioner, said, “To the contrary, there is evidence that the combinations of caffeine and alcohol in these products pose a public health concern.”

The FTC noted that some of the beverages contain as much alcohol as four regular or five light beers in addition to an amount of caffeine equivalent to three cups of coffee. The caffeine negates warning signs of intoxication, the FTC said, and referenced several recent incidents of consumers hospitalized after consuming caffeinated alcohol. According to the FTC letters, “These incidents suggest that consumers, particularly young adults, may not fully appreciate the potential effects of consuming caffeinated alcohol beverages.”

The agency urged the companies to “take swift and appropriate steps to protect consumers. Even in the absence of express safety claims, the very act of offering goods for sale creates an implied representation that the goods are reasonably fit for their intended uses and free of gross safety hazards. In addition, the non-disclosure of rare but serious safety risks may constitute an unfair practice.”

To read one of the FDA’s warning letters, click here.

To read one of the FTC’s warning letters, click here.

To read Sen. Schumer’s press release, click here.

Why it matters: The letters could be the beginning of the end for the caffeine-infused alcohol beverage industry. Several states – including Michigan, Oklahoma, Utah, and Washington – have already banned the drinks, and Sen. Charles Schumer (D-N.Y.) released a statement saying that the FDA plans to ban the drinks entirely. “Compounded with its health risks, beverages like Four Loko pose a unique danger because they target young people,” Sen. Schumer said, noting the “vibrantly colored” cans with “funky designs” are stocked next to energy drinks in most stores. The drinks “appeal to younger consumers, increasing the likelihood that the beverages will be consumed by young adults and creating a problem for parents and business owners who might be misled by the branding,” he said. Some of the companies have already begun selling non-caffeinated versions of their drinks; Phusion Products, the maker of market leader Four Loko, agreed to remove caffeine from its alcoholic beverages, although the company defended its product in a statement. “We have repeatedly contended – as do many people throughout the country – that the combination of alcohol and caffeine is safe. If it were unsafe, popular drinks like rum and colas or Irish coffees that have been consumed safely and responsibly for years would face the same scrutiny that our products have recently faced,” said co-presidents Chris Hunter, Jeff Wright, and Jaisen Freeman in a written statement.