A Washington Post article Tuesday that identified the American Health Foundation as an industry-supported organization was in error. Officials of the foundation said 90 percent of its support comes from government grants.

A major new federal study has found that at least one of every five future cases of cancer in the United States will come from exposure to carcinogens on the job.

The figures, which sharply contradict much lower estimates made recently by industry, were made public yesterday by Health, Education and Welfare Secretary Joseph A. Califano Jr.

He said the study, by the National Cancer Institute and the National Institute and the National Institute of Environmental Health Sciences, also showed that occupational exposure to asbestos alone may cause 2 million premature cancer deaths in the next three decades - roughly 17 percent of the total number of cancer deaths expected during that time.

In a speech delivered to the AFL-CIO National Conference on Occupational Safety and Health here, Califano called the still unreleased study's findings "alarming" and said they would lead to increased emphasis on prevention rather than treatment of cancer.

The three-day conference, the first of its kind to be called by the union, drew a strong showing from Carter administration officials, with speeches by Califano, Vice President Mondale and Labor Secretary Ray Marshall.

The administration officials sought yesterday to counter recent criticism that they have been willing to ease up on environmental and worker safety regulations in an effort to curb inflation.

"It is, in my judgement," said Califano, "myopic to argue that programs to protect workers are inflationary - if we do not count in our calculations what those programs buy: safety, health and often greater productivity."

Mondale and Marshall drew cheers from union representatives with pledges that the administration would continue to oppose a proposed amendment to the Occupational Safety and Health Act that would exempt businesses with fewer than 10 employes from federal safety and health investigations.

Laborr leaders have bitterly citicized the admendment, which passed the Senate and is scheduled to go before a House-Senate conference committee this week. AFL-CIO President George Meany yesterday called the proposal a "killer amendment" and warned that "it will turn several million workplaces into deathtraps."

Mondale promised that the administration would "work overtime" to defeat the amendment. But he did not say whether Carter would veto the bill if the amendment were included.

In his speech, Califano said he was using the conference as a forum to unveil the results of the study.

Noting that earlier industry estimates of the number of cancers related to occupational exposure ran between 1 and 5 percent, Califano, quoting from the federal study, said, "If the full consequences of occupational exposures in the present and the recent past are taken into account, estimates of at least 20 percent appear much more reasonable and may even be conservative."

Other federal health officials familiar with the study said the researchers found that the number of occupational-related cancers may run to 40 percent of all cancer in the country, the officials told The Washington Post yesterday.

The federal report also noted that industry estimates on occupationally related cancers in the past have lacked scientific documentation.

The researchers said that during the next 30 to 35 years the average number of cancers directly related to asbestos exposure will average 67,000 per year. Last year about 375,000 cancers were reported, excluding cancers of the skin, federal officials said.

The federal estimates on occupationally related cancers were based on past exposure of workers to carcinogens, the study said. "There is also sound reason to assume that the future consequences of present-day exposure to carcinogens in the work-place will be less than those of exposure in the recent past," it concluded.

The study noted that eight other carinogenic substances found in the workplace may cause cancers equal in their total number to asbestos. The highest excesses of cancers among workers were found in leather and shoe workers, coke oven workers, cadmimum production workers and metal mines, the study said.

The percentage of occupationally related cancers was quickly challenged yesterday by the head of health and environmental research for the Dow Chemical Co.

Dr. Perry Gehring said "what it boils down to is that Califano is all wet. He doesn't have the data to support those findings."

Gehring said industry estimates of work-related cancers were drawn from studies by the International Agency for Research on Cancer in France and the American Health, Foundation, an industry-supported organization.