E. I. du Pont de Nemours & Co., unveiling a detailed health study of its employes, said yesterday that formaldehyde does not pose an excessive health risk to humans.

The study was released on the same day the Environmental Protection Agency came under sharp criticism from Congress for failing to regulate exposure to formaldehyde, which has been shown to cause cancer in animals.

Du Pont undertook a review of its employe health records in 1980 after the results of the animal tests were first discussed.

"The results of our study . . . suggest that formaldehdye has not caused cancer in humans," said DuPont's medical director Bruce W. Karrh.

Du Pont, which maintains a detailed health registry of current and former employes, analyzed cancer deaths from 1957 through 1979 at eight of its plants that manufactured or used formaldehyde. Of the thousands of employes who worked during that 22 year period, Du Pont said it knew of 481 who died of cancer. Of those, 142 had been or could have been exposed to formaldehyde, while 339 were not, Du Pont noted.

Du Pont concluded that "cancer mortality rates in the company's formaldehyde workers were no higher than the rates among those who had not worked with the material," after taking employe smoking habits and other factors into account, to ensure a meaningful comparison between the two groups.

Additionally, Du Pont said that even though formaldehyde caused a large number of nasal cancers in the animal tests, no cases of nasal cancer were found among its employes.

Du Pont's study is certain to add to the controversy that now surrounds formaldehyde and the actions the government has taken to curb human exposure to the chemical.

Last February, the Consumer Product Safety Commission banned foam insulation made with formaldehyde after concluding it posed a health risk to consumers. The CPSC based its findings primarily on tests in which rats and mice were exposed to large doses of formaldehyde. At the time, the agency said there were no adequate human studies that demonstrated that the chemical was not a health risk.

However, about the same time, the Environmental Protection Agency concluded that there was not enough evidence--animal or human--to justify any action against formaldehdye.

That decision was attacked by the chairman of the House Science and Technology's oversight and investigation subcommittee, Rep. Albert Gore Jr. (D-Tenn.), yesterday in a day-long hearing.

"EPA's decision discounts more than a decade of science and experience by federal agencies during which careful peer and public review led to widespread acceptance of principles for assessing the human risk from potential chemical carcinogens," Gore said.