Sen. Howard Metzenbaum (D-Ohio) charged the State Department yesterday with a "serious failure of responsibility" in attempting to kill a Justice Department investigation of the worldwide uranium cartel.

The charges, which will be sent to the Senate Foreign Relations Committee, surfaced as Metzenbaum, chairman of the Senate Antitrust subcommittee cleared the nomination of John Shenefield for the No. 3 job in the Justice Department.

Metzenbaum has been involved in dispute with Shenefield, outgoing head of the antitrust division, ever since Shenefield's 1973 decision not to seek a felony indictment against Gulf Oil Corp, and others engaged in international uranium sales. Instead, Gulf was charged with a misdemeanor violation and fined $40,000.

At a hearing, Metzenbaum accused Shenefield of "less than vigorous antitrust enforcement" in his handling of the case, but said he will not object to Shenefield's confirmation to the new job of associate attorney general. The Senate Judiciary Committee is expected to confirm Shenefield next week.

Metzenbaum charged that documents obtained after a court suit indicate that the State Department, reacting to pressure primarily from the Canadian government, failed to inform antitrust officials after learning of the formation of the uranium cartel in 1972.

Noting that the views in a prepared statement were his own, Metzenbaum concluded that there is no evidence that Shenefield acted improperly in overturning a staff decision recommending felony indictments in the grand jury probe.

Shenefield has denied repeatedly that State Department pressure influenced his decision in the complex case.

Shenefield told the Senate panel that the case points out the difficulties faced by the nation's trust busters when investigating antitrust violations involving multi national companies.Shenefield and Metzenbaum agreed that legislation in this area merited congressional study.