A Food and Drug Administration official with considerable power over authorization decisions for e-cigarettes and products to curb smoking resigned on Tuesday to work for Philip Morris International.

The center for tobacco products had a chief of the office of science. Brian King, the center's director, wrote in a memo on Tuesday that Dr. Holman would be joining Philip Morris immediately. The memo said that Dr. Holman had taken a leave of absence and was looking for a new career.

Mr. King praised Dr. Holman for his 20 years of work at the F.D.A., where he has in recent years been responsible for reviewing marketing applications for e-cigarettes and other nicotine-delivery products. Dr. Holman said in an interview on Wednesday that his role at Philip Morris had been broadly defined, but that he would work on tobacco harm-reduction efforts and give feedback to the agency.

The tobacco control division is under review by the agency's commissioner. In April, the director of the division retired.

The revolving door between federal officials and the industries they regulate is a concern to critics. Philip Morris's IQOS, a "heat-not-burn" tobacco device, has raised questions about agency approvals. IQOS is not sold in the US because of patent litigation, but if that were to be resolved, the device could face new F.D.A. reviews.

Federal rules don't stop an official from overseeing regulatory matters one week and joining a corporation with products under review the next.

It's legal. Carome is the director of the Public Citizen health research group. This type of revolving door move hurts public confidence in the agency.

Federal rules prohibit Dr. Holman from appearing before the F.D.A. on matters in which he participated personally and substantially during government service.

ImageDr. Holman
Dr. HolmanCredit...U.S. Food and Drug Administration
Dr. Holman

He consulted with ethics lawyers before starting job discussions. He thought that Philip Morris was committed to moving smokers to noncombustible and less harmful products.

The actions they are taking are in line with the goal. I will not be helping them sell more cigarettes, but the opposite.

He said that he could have left the agency a long time ago if he'd wanted to. The F.D.A.'s decision- making was criticized by some public health experts.

An associate professor of public health and law at Ohio State University said that it was embarrassing for the F.D.A. to have its employees go to a company that was a leading manufacturer of death.

Representative Raja Krishnamoorthi was critical as well. He said that the revolving door between F.D.A. and the industries it regulates is disturbing. P.M.I. may argue that their hire is proof of their commitment to taking the health impacts of its products more seriously, but I won't hold my breath.

As head of the F.D.A. science office, Dr. Holman played a key role in approvals of electronic cigarettes and similar devices, which manufacturers have had to submit for review to stay on the market.

The Philip Morris product IQOS was one of the approved products. It is sold in many countries. U.S. sales are expected to resume next year, but may have to go through another review before that.

Critics of the IQOS approval include a retired professor of medicine and his colleagues at the University of California, San Francisco, who published a study saying the device contained toxins, some potentially carcinogenic and some at higher levels than in cigarette smoke. A study in the journal Tobacco Control concluded that the agency's approvaldisregarded valid scientific evidence and misapplied the public health standard mandated by law.

Dr. Glantz said that Dr. Holman ignored another study that showed that e-cigarette use was not associated with reduced rates of smoking. The problem of dual-use, or using cigarettes and e-cigarettes, which is worse for overall health, has not been addressed by approvals. Dr. Glantz said, "Good riddance."

He said that the person who signed off on the approvals was him. They deal with all of these issues by relying on out-of- date studies.

In June, the F.D.A. denied marketing authorization to Juul Labs. The agency announced a review of its decision since then.

The authorization granted to Philip Morris was one of the reasons it would likely prevail.

Many agency decisions have their critics but he believed IQOS authorization was justified on a full review of the data.

Philip Morris said in a statement that it was committed to helping existing adult smokers access scientifically substantiated smoke-free alternatives. We are looking forward to having him join our team.

A former F.D.A. chief of staff has joined the company as a vice president of government affairs.