Seven years after the first toxic-shock syndrome deaths were linked to highly absorbent tampons, the government has given up on industry voluntarism and is moving to require manufacturers to label the absorbency of their products.

The Food and Drug Administration has taken the first steps in the lengthy process of establishing rules for uniform labeling of tampons. The rule would make it possible for the teen-age girls and young women who are the most frequent victims of the disease to choose less-risky products.

In 1982, the FDA required tampon manufacturers to warn women against toxic-shock syndrome and advised tampon users to select the minimum absorbency needed.

But "what one company calls regular may be super absorbent to another," said Diana K. Temple, an industry analyst at Salomon Brothers Inc.

The seven-year lag reflects several factors: early scientific uncertainty on the cause of toxic shock, the Reagan administration's preference for voluntary rather than mandatory standards, and the highly competitive nature of the industry.

Toxic-shock syndrome, which has killed 127 people through May of last year, is a rare illness that has struck 2,962 people since it was identified in the late 1970s. Nearly 80 percent of its victims have been menstruating women, most of them young.

Meanwhile, a group of consumers, manufacturers and FDA representatives met for two years under the auspices of the American Society for Testing and Materials, a standard-setting group, in an effort to agree on voluntary language for tampon labeling.

"We started out very cordially," said Judith Belk, a member of the task force and cochairman of Woman Health International, "but it soon became very apparent we weren't working toward the same goals. They had monetary things to consider."

Paul Konney, vice president and general counsel of Tambrands, the manufacturer of Tampax, said voluntary efforts broke down because of a "dichotomy" between manufacturers, some of which wanted a "point" system, which would assign a single number to absorbency based upon a standardized test, and some of which wanted a "range" system, under which absorbency would fall within a range of numbers.

The point, he said, was to "enable manufacturers to agree without changing their product substantially."

Tambrands, the industry leader with 60 percent of the market, fought for a "range," the system under consideration by the FDA.

International Playtex, makers of the No. 2 brand with about 30 percent of the market, has already placed absorbency labels on its packages using the "point" system. The difference between regular and super, according to the labels, is the difference betwen 10 and 11 grams of absorbency. Under the "range" labeling method, both sizes might be grouped in the same category, masking the differences.

Consumer groups had fought for standardized wording, under which "super" and "regular," for example, would mean the same absorbency for all brands.

Although the FDA submitted its proposal to the Office of Management and Budget for inclusion in the Regulatory Program of the United States, a government-wide compilation of regulatory activities, it remains far from reality.

Les Weinstein, the "contact officer" on the rule in the FDA, said the proposal must still be approved by the FDA commissioner, Health and Human Services secretary, and the Office of Management and Budget, which reviews all rules for efficiency and necessity.

The tampon market has changed considerably since toxic shock was at its height in 1980. Procter & Gamble's Rely tampons, the brand most associated with the syndrome, was voluntarily removed from the market that year. After a Harvard study suggested that a man-made fiber called polyacrylate rayon might induce bacteria to manufacture more of the toxin that causes the disease, Playtex and Tambrands voluntarily removed products with these substances from the market in 1985.

Symptoms of toxic-shock syndrome include a high fever, vomiting, dizziness, rashes and diarrhea.

"There is no reason for them to take all this time," said David A. Swankin, general counsel of the National Consumers' League, "and then not do it right."