The Chemical Manufacturers Association may have influenced the National Cancer Institute to suppress a study by an international health agency of the risk posed to chemical workers by exposure to benzene, a congressman charged yesterday.

In announcing that he would investigate a possible connection between the chemical industry trade group and the institute, Rep. David R. Obey (D-Wis.) released what he said was a copy of an internal CMA memorandum discussing the upcoming publication of a pamphlet by the International Agency for Research on Cancer on the risk of contracting leukemia from exposure to benzene. The memo refers to conversations NCI staff members may have had with staff members of the international agency about concerns they had over publication of the pamphlet.

"I find this memo to be a deeply disturbing document," Obey wrote Dr. Vincent DeVita, director of the National Cancer Institute. "It suggests that representatives of the Chemical Manufacturers Association obtained the agreement of National Cancer Institute representatives to attempt to block publication of important scientific data which could have led to lowering of the cancer risk faced by millions of Americans."

Dr. Richard Adamson, director of NCI's division of cancer cause and prevention, said that he had tried six times to contact Obey's office to discuss the charges and had failed to reach the congressman. Adamson said that Scott Lilly, an Obey staff aide, had returned one of his calls but did not reach him. Lilly said he tried several times to reach Adamson by phone but was told Adamson was out of town.

"There is no attempt to suppress any IARC monograph," Adamson said. "The monograph in question will be at the printer's in a month and will be published about five weeks later."

Adamson said there is some concern among NCI staffers over the IARC's plans to assess the risks from small exposures to benzene. He said these concerns will be raised May 17 when the National Cancer Advisory Board meets in Washington.

"I think that what we will say is that if IARC gets into the business of risk assessment, they should get into it very carefully," Adamson said. "This is a new area for a research agency like IARC and is an area that is fraught with difficulty."

Adamson denied Obey's charge that NCI staffers had discussed their concerns with the manufacturers association but a CMA spokesman confirmed that such discussions had taken place.

"We met with somebody from NCI on Jan. 15," CMA spokesman Jeff Van said. "The reason we met with somebody was to express our concern that IARC may be using flawed data on the health effects of benzene. We were fearful this could give a distorted picture of the risks from benzene exposure that could serve as a poor foundation for conclusions about cancer.

"We didn't try to block any publication of anything," Van said. "I think Congressman Obey has misunderstood or misinterpreted something along the way."

The "flawed data" mentioned by Van is apparently contained in a paper, published by the Occupational Safety and Health Administration during the Carter administration, which linked as many as 35 percent of U.S. cancers with occupational exposure to carcinogenic chemicals. There is apparently widespread disagreement about this data.