The Senate Commerce Commmittee said yesterday that a federal investigation will be conducted into allegations that the chairman of the Consumer Product Safety Commission, Terrence M. Scanlon, misused government property and acted improperly on behalf of companies subject to the agency's regulation.

The investigation -- which will be conducted by the General Accounting Office, the investigative arm of Congress -- will begin immediately, the committee said.

"It is claimed that as many as 30 individuals can substantiate the allegations that have been made against Mr. Scanlon," said Sen. John C. Danforth (R-Mo.), chairman of the Senate commerce committee. "I don't know if that is the case, but we have a constitutional duty to find out."

The allegations against Scanlon were made at his confirmation hearing more than a month ago by Joan Claybrook, the president of Public Citizen, a national public interest group founded by Ralph Nader.

Claybrook, who called for a federal investigation, charged Scanlon with using his office staff and government property to conduct personal work on government time and at government expense.

Claybrook also charged that Scanlon violated CPSC rules governing meetings with companies and provided internal agency information to firms that were targets of CPSC investigations for safety violations.

Scanlon, who has been serving as CPSC chairman on a recess appointment since last Dec. 31, has denied both allegations. Scanlon, the highest-ranking Democrat in the Reagan administration, was conducting hearings yesterday in Los Angeles on all-terrain vehicles and could not be reached for comment.

"Mr. Scanlon denies all the charges, and I have no reason to doubt his word," said Danforth. "Nonetheless, we are all best served if a thorough investigation of the charges is undertaken."

Danforth said that, "Since the committee does not have the manpower or expertise to conduct this kind of investigation, we have asked the GAO for assistance."