The initiative is expected to be unveiled as part of the administration’s “unified agenda,” a compilation of planned federal regulatory actions released twice a year, according to the individual with knowledge, who spoke on the condition of anonymity because they did not have authorization to discuss the issue.

The policy would fit with a major goal of the White House — to cut cancer deaths. As part of the White House’s retooled cancer moonshot announced this year, President Biden promised to reduce cancer death rates by 50 percent over 25 years. About 480,000 Americans die of smoking-related causes each year, and tobacco use remains the No. 1 cause of preventable death in the United States.

The decision to pursue a policy to lower nicotine levels marks the first step in a lengthy process, and success is not assured. It could take at least a year for the Food and Drug Administration, which regulates cigarettes, to issue a proposed rule, experts say. After that, the FDA would have to sift through comments from the public before issuing a final rule.

Opposition could delay or derail the effort — especially if the regulation was not completed before Biden left office. A president elected in 2024 could tell the FDA to stop work on an unfinished rule. The tobacco industry, which is sure to be fiercely opposed to such a drastic change in its products, could challenge a final regulation in court.

The FDA has supported reducing nicotine levels in cigarettes for years but has never secured the necessary upper-level support, including from the Obama White House. The Trump administration’s first FDA commissioner, Scott Gottlieb, said he wanted to lower nicotine levels as part of a broader tobacco policy, and the agency took an early step in 2018 by publishing an information-gathering notice. But the idea never had full-throated White House backing and was shelved after Gottlieb left the administration in spring 2019.

Supporters say slashing nicotine, the addictive ingredient in cigarettes, would be a milestone in public health that would save millions of lives over generations. In another significant move to reduce smoking-related deaths, the FDA in April proposed banning menthol cigarettes, the only flavored cigarettes still permitted.

The Wall Street Journal first reported that the administration was planning to pursue the nicotine-reduction policy.

Mitch Zeller, who recently retired as director of the FDA’s Center for Tobacco Products and is a longtime advocate of reducing nicotine in cigarettes, acknowledged it could take years for such a requirement to take effect.

“The most important, game-changing policies take a long time, but it is worth the wait because, at the end of the day, the only cigarettes that will be available won’t be capable of addicting future generations of kids,” Zeller said.

Matthew L. Myers, president of the Campaign for Tobacco-Free Kids, an antismoking group, said slashing nicotine levels “would produce the greatest drop in cancer rates and make the biggest difference” of any public health measure under discussion by the administration.

Guy Bentley, director of consumer freedom at the Reason Foundation, a libertarian think tank, criticized the plan.

“In practical terms, the proposal would ban most cigarettes currently sold in America,” Bentley said. “Combined with the Biden administration’s proposed ban on menthol cigarettes, this would amount to an effort similar to the prohibition of alcohol in the 1920s” — and would ultimately fail, he said.

Bentley said rather than cutting nicotine levels in cigarettes, the administration should promote safer alternatives such as e-cigarettes. The FDA is reviewing thousands of applications from e-cigarette manufacturers to determine which should be allowed to remain on the market.

In early 2021, the FDA pitched the nicotine-reduction strategy in talks on tobacco issues with the White House and the Department of Health and Human Services. At the time, the White House gave the FDA the go-ahead to pursue a policy banning menthol cigarettes, but senior officials put off a decision on reducing nicotine levels, according to people familiar with the issue who spoke on the condition of anonymity because they were not authorized to discuss internal deliberations.

Backers say the idea is a natural fit with the White House cancer moonshot because it would slash cancer deaths and does not require a big outlay of government money given that the FDA has been working on the issue for years.

“There’s a long arc to major policymaking, and the Biden administration’s commitment to advance that effort will mean it gets done,” Gottlieb, the former FDA commissioner, said. The combination of reduced nicotine levels and appropriate regulation of other sources of nicotine for addicted adult smokers, such as e-cigarettes, could be “one of the most impactful public health efforts in modern times,” he said.

Nicotine, a chemical that occurs naturally in the tobacco plant, does not cause cancer. But its highly addictive properties make it hard for people to quit using cigarettes, whose smoke contains harmful constituents that can cause lung cancer and heart disease.

Myers, of the Campaign for Tobacco-Free Kids, predicted an FDA requirement to slash nicotine in cigarettes would trigger “the greatest reaction from the tobacco industry of any action ever taken by the government. It is an existential threat despite claims [by cigarette companies] that they support a smoke-free future.”

The 2009 Family Smoking Prevention and Tobacco Control Act gave the FDA the authority to regulate cigarettes, including cutting nicotine to minimally and nonaddictive levels. Under the law, the FDA may not ban cigarettes or reduce nicotine levels to zero. But it is permitted to set product standards that dictate components, ingredients, additives and nicotine yields for cigarettes, if those standards are needed to protect the public health.

Reynolds American, one of the nation’s biggest tobacco companies, did not respond immediately to requests for comment. Altria said it would comment after the administration announces any nicotine-reduction plans.

In the past, Altria has said that, if limits are put on nicotine levels in cigarettes, the FDA must ensure that adult smokers have greater access to noncombustible alternatives and accurate information about switching to them. The company also has argued that reducing nicotine in cigarettes would be devastating for tobacco retailers, endangering hundreds of thousands of jobs.

Other opponents of such a policy will probably argue, as they have in the past, that reducing nicotine to nonaddictive levels is a de facto ban on cigarettes, prohibited by law, and that science does not support such a move. They also are likely to say that slashing nicotine would boost demand for products on the black market.

Zeller countered that the science supporting slashing nicotine levels is well-established. He said researchers have determined the levels at which nicotine is minimally addictive or nonaddictive. And he said they also have concluded that reducing nicotine should occur in “one fell swoop” because a gradual decrease would encourage smokers to smoke more to compensate to get the same amount of nicotine.

In its 2018 notice, the FDA said lowering nicotine levels to minimally or nonaddictive levels “could give addicted users the choice and ability to quit more easily, and it could help to prevent experimenters (mainly youth) from initiating regular use and becoming regular smokers.”

An agency-funded study published in 2018 in the New England Journal of Medicine found that lowering nicotine levels could save more than 8 million lives by the end of the century. The number probably is a little lower now because the percentage of adult smokers has declined in recent years from the 15 percent rate used in the study to about 12 to 13 percent.