The cigarette that 60 million Americans will be smoking today is not the same is it was 25 years ago.

This became startling plain last week despite the storm over a federal cancer scientist's view that moderate smokers of some brands today may face no more extra risk of deadly disease than smokers of two cigarettes daily once faced.

The changes that made his statement at least arguable are partly in the tobaccos, partly in the paper, partly in the manufacture, and most of all in the increasingly sophisticated filters of most cigarettes.

The week - while it saw fear that many misguided people might now mistakenly think some smoking perfectly safe - also saw new pressure on the tobacco industry to make larger numbers of safer cigarettes.

Several scientists said the government's safety assessment should include disclosure and testing of cigarette makers' secret chemical additives - which give cigarettes that contain less tar and nicotine some sort of taste.

In statements and interviews, scientists agreed that no smoking - cigarettes, cigars, pipes or hookahs - is without risk.

Still, most agreed too that a seldom acknowledged revolution has been occurring in the nature of the slim, white cigarette.

Dr. Arthur Holleb, medical director of the American Cancer Society, said the controversial new report by Dr. Gio B. Gorl of the National Cancer. Institute shows the tobacco industry's "demostrated ability" to make less hazardous products.

He said the Gorl-report - and a July American Medical Association report, commissioned by cigarette firms, that reconfirmed tobacco's dangers - place "moral pressure" on the firms to stop making and promoting more hazardous brands.

Dr. El Cuyler Hammond, cancer society vice president and chief statistician, and coauthor of the famed 1954 report that was the first to positively link cigarettes with lung cancer, said: "Before 1954, when low-tar, low-nicotine Kents appeared, the lowest cigarette in tar and nicotins had more than the highest today."

Dr. Lawrence Garfinkel, Hammond's associate, said that in the early 1950s - "from what we can piece together from a period when there wasn't much testing" - the "worst" brand had about 45 milligrams of nicotine per cigarette. Among the more popular brands of cigarettes today, the highest in both of these noxious compounds are Herbert Tareyton non-filter kings (29 and 1.8) and Chesterfield nonfilter kings (28 and 1.7).

"In general," Garfinkel said, "30 percent of all brands have less than 15 milligrams of tar" and correspondingly less nicotine, "and another 60 percent are between 15 and 20 milligrams. So the companies have gone very far. They've sort of weaned people away from the old cigarettes."

Cigarette markers have called their low-tar, low-incotine brands the fastest growing part of their market. But Gorl looked at several possible cigarette toxins or poisons: tar, noctine, carbon monoxide and others. He found only five brands so low in all that a smoker could smoke more than 15 cigarettes daily without exceeding the pre-1960 "two-cigarette-a-day" risk: a Carlton Menthol smoker could smoke 23; Now Menthol, 18; Nows or Strides, 17; and Cariton, 16.

These brands had just under 2 percent of all sales last year. Brands that would permit someone to smoke between three and eight cigarettes daily, by the same standard, had 17 to 18 percent.

To Gorl, however, the less hazardous brands are the "forerunners" of many he thinks will be successfully marketed "in the next few years." With further research, he adds, "considerable improvement is still possible."

Dr. E.L. Moore of the Agriculture Department, a leader in guiding development of less hazardous cigarettes, and Dr. Fred Bock of Roswell Park Memorial Cancer Institute in Buffalo, a leading scientist in the field, agreed.

They told how tobacco, tobacco blends, curing, cigarette papers and burning rates have been changed to make cigarettes less deadly.

Still, said Bock, no "single chemical agent" in tobacco or smoke has yet been identified as the guilty carcinogen, or cancer causer, though there are indications that nicotine is a "co-carcinogen," which helps other elements in the environment cause cancer.

"What we do know," Bock said, is that smoking does cause cancer, heart disease and other illnesses, possibly by a combination of "a large variety of agents." Also, that there is "a strong correlation" between the amount of tar and nicotine and "cancer production."

Also, he said, "there is good evidence now of a relationship" between the reduction of tar and nicotine in cigarettes and improved health statistics.

He said the greatest single improvement in cigarettes has been in adding filters that screen out as much as 98 percent of the tar and nicotine. Filter cigarettes constitute 92 percent of the cigarettes sold today.

But what comes through some filters may be largely hot air unless it is accompanied by methol, various tobacco concentrates or other secret "flavorings."

Bock, Hammon, Garfinkel and Dr. Sidney Wolfe, head of the Ralph Nader Health Research Group, called on the government to require cigarette makers to disclose the nature of all additives to try to make sure that they are not themselves hazard. Bock thinks the government should keep the information confidential to protect trade secrets.

But "I think the companies ought to tell me what's in their cigarettes," Hammond said. "I've asked some, and I still don't have the slightest idea."

Sen. Edward M. Kennedy (D-Mass.) has introduced a bill to require the government to try to discover the ingredients, but it would not make reporting mandatory.

The bill would also add a 5- to 50-cent-a-package tax on cigarettes, depending on tar and nicotine content. No one expects any such bill to sail through Congress.

Gori - who started last week's fuss - tried at the end of the week to set his position straight. For the public health, he argued, the cancer institute, the Agriculture Department and the cigarette companies must continue to develop less harmful cigarettes.

"I have consistently maintained that no one should smoke," he repeated. "The only safe cigarette is the cigarette that is not lit."