The chairman of a National Academy of Sciences committee reviewing the nation's current radiation exposure levels told a House subcommittee yesterday he believes the current occupational exposure limit is 10 times too high and "long overdue for change."

Dr. Edward P. Radford of the University of Pittsburgh's Graduate School of Public Health told the House Subcommittee on Health and the Environment that the current level of five rem per year, if allowed a worker for 40 years, would make the worker's "subsequent cancer risk more than 100 percent greater than expected" for the normal population.

"This degree of cancer risk is unacceptable, in my opinion," Radford said.

He said the occupational exposure limit "should be reduced at least to 500 millirem .5 rem per year . . ." p Radford's unexpected state- 500 millirem (5 rem) per year . . ."

Radford's unexpected state-voted to a controversy over the results of a long-term radiation health study of workers at the government's nuclear facilities at Hanford, Wash.

An earlier witness, Dr. James L. Liverman, acting assistant secretary for environment in the Deaprtment of Energy, told the subcommittee he believed "re-evaluation of all available information on the effects of . . . radiation has not indicated a need for any significant change in the currently used guidelines for the protection of the general public or workers in the nuclear industry."

Liverman was not in the committee room when Radford made his statement.

Radford's group, officially called the committee of Biological Effects of Ionizing Radiation (BEIR), was put together to update the so-called 1972 BEIR report, the basis for current radiation exposure standards. It is expected to make its report in October.

Radford, who served on the 1972 group, told the subcommittee he believes "new evidence indicates that the risk of cancer is substantially greater" than thought just six years ago, particularly at lower levels.

Liverman, on the other hand, said "the does-effect relationship of low-level irradiation is incomplete . . ."

Yesterday's testimony illustrated another area of disagreement over the long-term effects of low-level radiation.

The old Atomic Energy Commission began a study of the Hanford workers in 1964. The prime investigator was Dr. Thomas F. Mancuso of the University of Pittsburgh.

In 1975, before Mancuso had made any conclusion in his study, his government contracting officer, Dr. Sydney Marks, decided he wanted to move the contract to an organization working out of the U.S. government facilities at Oak Ridge, Tenn.

In 1976, the last year he had the contract, Mancuso hired two English scientists, Dr. Alice Stewart and Mr. George Kneale, to analyze the data he had collected over the previous 12 years.

As Stewart explained it to the subcommittee yesterday, at the low levels of radiation to which the Hanford workers were exposed, "we found 6 to 7 percent more than expected probably died from radiation-induced cancer."

Although Liverman and other Energy Department officials have sharply criticized the Mancuso study, Dr. George B. Hutchison, a Harvard School of Public Health professor and DOE consultant, who accompanied them at the hearing, said he agreed with its basic findings of increased cancers. He did take issue with the extent of risk found by the Mancuso group.

Subcommittee Chairman Paul G. Rogers (D-Fla.) noted that instead of the Hanford follow-up work going to Oak Ridge, it now will be handled by Pacific Northwest Laboratories, a subsidiary of Battelle Inc.

Marks, the contracting officer for the Mancuso study, left the government in June 1976 and now manages for Pacific Northwest. He has been one of the most vocal critics of the Mancuso study's findings.

Liverman was asked yesterday by Rogers why he transferred the medical research on nuclear radiation effects to Battelle, which has never before run such a study and has a least $20 million in government contracts to develop nuclear power sources. Liverman never got a chance to answer that question. He will return before the subcommittee today.

Meanwhile, the Defense Nuclear Agency announced yesterday it had established a toll-free telephone number for veterans of the nuclear weapons tests of the 1950s.

The agency is attempting to locate the servicemen to determine if they have any aftereffects from radiation received at the tests.

The number is 800-638-8300.