The Cambridge City Council last night may have killed a proposal referendum that would ban the manufacture of nuclear weapons in the city.

By a four to four vote the council failed to pass a motion to place the Nuclear Free Cambridge proposal on the November ballot.

Referedum proponents insisted after the meeting that approval was unnecessary and that as long as their proposal had the proper number of certified petition signatures it would go before the voters.

But the city manager for opponents of the referendum said that state law requires council backing for a binding initiative to be placed on the ballot and that the lack of a majority meant the effort had failed.

All sides agreed that the statute in question is hazy and conceded that the state election commission will likely be forced to interpret it. It is doubtful that either party would accept that ruling however and the matter could well end up in superior court lawyers for both sides predicted.

Last night's motion was the second attempt by opponents in a week to keep the question off the ballot. On Thursday lawyers for Cambridge's Charles Stark Draper Laboratories--a nuclear research firm which would be seriously affected by the measure--challenged the validity of petition signatures before the state ballot law commission. The commission which is separate from the state election panel continued hearings yesterday and is required to issue a ruling by Thursday.

Lawyers for Nuclear Free Cambridge and for Draper Labs have hinted that if that commission's ruling does not go their way they will also take that judgement to a higher court.

Even if the referendum overcomes both of these challenges, it will not be in the clear legally. Should it emerge from the courts in time to make the November ballot, and should it secure the necessary voter approval. Draper officials have promised to battle the law's constitutionality.

While a handful of local companies would be affected by the question. Draper has the largest stake in the current fight--85 percent of its work goes toward development of the MX missile, the Trident class submarine and other nuclear weapons, officials have said.

The Central Square lab employs about 1800 workers. Although the proposal--which would go into effect in October 1985--would relocate effected workers, organized labor has joined the opposition. Mayor Alfred E. Vellucci told his fellow councillors.

The city council vote came after more than an hour of confusing legal discussions, and a heated exchange between Councilor David Wylie, a strong supporter of the measure, and Draper Vice President John F. O'Connor. A large crowd of observes, which spilled over into halls and the upstairs galleries, stayed for the whole discussion, despite the sweltering heat mitigated only by one small clacking electric fan.

Wylie, who often raised his voice in an impassioned speech in favor of the measure said, "We are in more danger than we have ever been in the history of this city. We've never been more concerned that at the push of a button this whole city can be destroyed."

O'Corner responded that the Soviets would strike retaliatory missiles first and noted that Draper does not contain any such weapons Wylie O'Corner said was "misleading" the voters.

When the question finally came to a vote, the councilors split along customary partisan lines. The four members of the Independent slate--considered the city's conservative faction--voted no. They were Daniel Clinton. Thomas Danehy. Leonard Russell, and Walter J. Sullivan Three Cambridge Civic Association (CCA) members--Francis H. Duehay '55. Saundra Graham, and Wylie--joined the unaffiliated Vellucci in voting yes David Sullivan, the fourth (CCA) member, did not participate in the vote, saying that his position with the state election commission placed him in a conflict of interest.

After the meeting, lawyers for both sides expressed partisan sentiments as strong as those evident in the council vote.

Robin Freedman, counsel for Nuclear Free Cambridge, said after the meeting that "under the law it should go on the ballot." But Kenneth A. Cohen, the Draper attorney, said. As I understand it, they voted go on the merits on the measure.

City Solicitor Russell B. Higley, who would rule on the status of the proposal said he thought the proposal was blocked unless the council changed its mind, although he said he would research the question further.

City Manager Robert W. Healy said there are "two schools of thought" and that the election commission will have to take it up."

The council also passed a resolution asking Healy to hire a constitutional lawyer pro bono to advise the councilors on the constitutionality of the measure although Healy said he doubted he could find a lawyer acceptable to both sides in time.

Opponents have raised two constitutional questions. The first is whether or not the measure violates First Amendment freedoms by restricting certain research. The second is whether the city is overstepping its sovereignty bounds by restricting what has been authorized by the federal government.

The nuclear debate came during the council's second and final summer meeting which ended at 12:30 a.m. In the first part of the meeting, the city officials rejected another request to place a referendum on the ballot. The Cambridge Rent Control Coalition had asked the councilors to place on the ballot a non-binding six-part plan to stem tenant displacement.

Willium Noble, a member of the Coalition said the organization would over the next 10 days conflect signatures as put the question before the voters. Because it would be nonbinding, the tenant question follows different procedures than the Nuclear Free Cambridge initiative.

In other action at the seven hour session the councilors agreed to delay until a public hearing a request from Draper Labs to build a pedestrian bridge between its two buildings.

Graham used her charter tight during a public hearing to delay consideration of an application for an Urban Development Action Grant by a private development firm in the Lichmere area. She said that the council had not been given enough time to examine whether the proposed development had too much luxury housing and not enough low and moderate income availabilities.

In another public hearing the council passed a proposal by Duehay instructing the city solicitor to investigate the legality of a rooming house located on 151-3 Mt. Aubum St. The council will await the report before deciding how to deal with that specific place and with what residents call an extreme proliferation of rooming houses in the Cambridgeport area.

John D. Solomon assisted with the reporting of this story