A staff member of an oil industry trade group told a Senate Committee yesterday that some of the internal documents he received secretly from the Department of Energy came to him in the mail in "a plain brown envelope with no return address."

American Petroleum Institute analyst John Iannone also told the Committee on Energy and Natural Resources that "nothing I did was for my profit or the profit of our members." The API represents the major oil companies.

The hearings grew out of the release of an internal API memo from Iannone to his superiors that revealed that he had obtained access to many DOE internal documents in advance of agency decision-making, and often in time for him to influence those decisions.

Congress Watch, a Ralph Nader consumer group, obtained the documents and released them two weeks ago, charging that the oil industry was receiving significantly more data than the public or consumer groups, and using the information to influence decisions at DOE.

Sen. Howard Metzenbaum, chairman of the committee, called yesterday's hearing to examine the "leaks problem" at DOE.

During the hearings. Metzenbaum produced an evaluation from the Congressional Research Service of the Library of Congress saying that one of the decision's Iannone claims to have influenced could have saved the oil industry $300 million.

In that case. Iannone said in one of his "quarterly reports" to his superiors, that he was able to "get them (DOE) to agree to a number of important changes." in their plans to monitor gasoline prices.

Iannone claimed to have convinced DOE to change the base month used for rationing from November 1977 to June 1977.

The Library of Congress study showed that, had rationing gone into effect, the change would have set gasoline prices a fracrion of a cent higher increasing annual revenues to the gas industry of $300 million.

However, the rationing plan was never used.

Throughout yesterday's hearings, Metzenbaum reiterated that Iannone was not being accused of doing anything illegal. Still, the Senator expressed concern that Iannone was able to get so much material by just asking DOE employees, while consumer groups that went to the trouble of filing Freedom of Information Act requests for the same, or similar, information, were denied such access.

Congress Watch's Mark Green told the committee that he would be happy if his organization would be allowed the same access accorded the API representatives.

Iannone, for his part, said none of the documents he was given were classified, and most of them were published by, or mentioned by, the energy trade press prior to coming into his hands.

He said DOE employee Gerald Emmer, of the Division of Petroleum Allocation Regulations, and other DOE staffers, made many documents available to him, including correspondence between congressmen and the DOE that had not yet been answered.

Toward the end of the hearings, Metzenbaum said his major concern wa not that the documents were given to the API, but rather "the ex parte nature of the meetings." He said if the documents were to be given out, they should be made public.

In two weeks, the committee will reconvene to question DOE employees involved in the dissemination of the information.