Last week the federal Food and Drug Administration quietly did something that it has never done before. For the first time in its history, the agency charged with protecting the public from harmful foods and medicines rejected a bid by the tobacco industry to put new products on the market, based on the fact that they posed a serious risk to public health.

Under a 2009 law supported by the Obama administration, the agency was granted the power to regulate cigarettes and other tobacco products, including cigars, loose rolling tobacco, chewing tobacco and snuff. But until now it had never used that authority to block the sale of such products.

So it was something of a milestone when the agency announced Tuesday that it had authorized two new kinds of Newport cigarettes made by the Lorillard Tobacco Company but rejected four other products manufactured by companies it declined to name. Agency officials said the law forbade them from identifying the rejected products.

The FDA's action may seem relatively modest given the scale of the destruction wrought by tobacco products. But in fact it represents a sea change in the agency's attitude toward cigarettes. Before the 2009 law was passed, cigarette manufacturers were free to operate virtually without any meaningful federal oversight or regulation. Individual states were allowed to determine where and how tobacco products were sold within their borders, but they had no control over the ingredients those products contained.

Moreover, all this was happening at a time when cigarettes increasingly were being recognized as a leading cause of death in this country. The federal Centers for Disease Control and Prevention estimates that smoking kills more people each year than HIV-AIDS, illegal drugs, alcohol use, motor vehicle injuries, suicides and murders combined. Some 443,000 Americans die annually from smoking-related illnesses; worldwide, tobacco kills about 6 million people a year. The World Health Organization estimates that every 6.5 seconds a current or former smoker dies.

Yet the FDA's announcement marked the first time in history that a federal agency has ever told a tobacco manufacturer that it couldn't market a new cigarette because of the threat it posed to public health. That's a testament to the political clout the tobacco lobby traditionally has wielded, but as public attitudes toward smoking — and the staggering health-care costs associated with it — continue to evolve, the FDA's action offers hope the country may finally be ready to back stricter standards for cigarette manufacturers.

The four products rejected by the agency as too dangerous to market were all found to pose public health risks above and beyond comparable products already on the market. Unfortunately, the FDA didn't reveal the kinds or amounts of chemicals they contained.

That makes it difficult to judge precisely why those products were considered unsafe, but more importantly it leaves up in the air the whole question of what level of risk the agency deems unacceptable when it reviews new products. Given the huge number of people who succumb to smoking-related illnesses each year, it's hard to imagine any amount of nicotine, menthol, formaldehyde or other toxic chemicals contained in cigarettes that could reasonably be construed as harmless.

Still, the FDA has taken an important first step toward greater oversight of the tobacco industry in order to keep manufacturers' most dangerous products off the market. That, along with public health campaigns aimed at dissuading teenagers from taking up the habit and more restrictions on where and when adults can smoke, may finally begin to push down the toll in lives taken by tobacco as a result of illnesses that are largely preventable.