The Maryland House of Delegates unanimously voted today, as one of the first acts of the 1981 General Assembly session, to set up an investigative committee to consider disciplining -- and possibly censuring -- Prince George's Del. Francis J. Santangelo for alleged violations of ethics law.

The unprecedented vote by 127 members of the House, including a subdued Santangelo, was made without any discussion of the charges against him and only a brief statement by House Speaker Benjamin L. Cardin that the issue be resolved "as promptly as possible," perhaps within a few weeks.

Earlier in the day Cardin urged Democratic delegates assembled for a closed party caucus to vote in favor of the investigative committee and warned that any other action "would leave a cloud over this body and the delegate."

Today's vote in the House followed a finding in the fall by the legislature's joint ethics committee that a "question of substantial conflict of interest" existed in Santangelo having lobbied for state contracts on behalf of a "big band" promotion company in which he later held an undisclosed financial interest.

Following ethics procedures enacted two years ago that are receiving their first test in this case, the ethics committee voted to request that Cardin, as speaker, introduce a resolution to begin the House investigation of Santangelo.

When it was approved, the resolution represented the first time in its history that the General Assembly has considered disciplining one of its own members.

The committee, which was set up today and held its first meeting behind closed doors, will either consider the transcripts of the ethics committee investigation this fall or hold its own hearings on the case. It will then recommend either that no action be taken against Santangelo or, at most, that he be formally censured by the House.

Santangelo would not comment today on the allegations against him -- in the past he has denied them -- or the decision to set up the investigation.

Before the resolution came up for a vote, the slim, moustachioed legislator wandered through the plush delegate's lounge behind the House chambers waiting for the announcement that House Resolution 1 was being considered.

A number of delegates, apparently uncomfortable with the idea of disciplining one of their colleagues, approached Santangelo with sympathetic murmurs about "bad press" and questions about his legal costs.

Said one legislator familiar with the charges against Santangelo, "People are uncomfortable (with a House investigation). Some of the things he did were simply not different from what any of us do."

When the vote was taken on the resolution, Santangelo joined in making it unanimous by flicking on a green light on the wall tally board. Afterwards, when the House had adjourned, Santangelo's wife rushed to his side, locked arms with him and led him down the steps of the State House. h

Today's vote was only the latest development in the investigation of allegations against Santangelo. The charges first surfaced in a Prince George's grand jury investigation in early 1979 after Maryland Attorney General Stephen H. Sachs asked the grand jury to determine whether Santangelo improperly used his office to land state contracts for Dana Promotions Inc. to stage dances at the state-run Ocean City convention hall.

According to the allegations, Santangelo tried to win the contract for Dana in 1976 by asking an aide to then-Gov. Marvin Mandel and a state senator for the Eastern Shore to use their influence with members of the state commission responsible for awarding the Ocean City contract.The commission awarded Dana the contract the following year. By the time that award was made in 1977 Santangelo had obtained a financial interest in the New Carrollton-based promotion firm, an interest that he failed to disclose in official documents required by state law.

Santangelo, filed an amendment to his 1977 disclosure form and listed a "profit sharing" interest in Dana during the grand jury probe. The grand jury cleared Santangelo in September 1979, but the issue continued when Sachs' office asked Cardin to look into the matter. Cardin then asked the ethics committee to begin an investigation in January 1980.

That investigation, which involved dozens of sworn interviews, focused on Santangelo's alleged use of his office for a company in which he would soon hold financial interest and into his failure to disclose that financial interest on required documents. The committee apparently was unable to document anything but the latter charge and it was that charge that led the ethics committee to push for the establishment of the House investigative committee, which was approved today.