Parties to pending unfair labor practice proceedings cannot use the Freedom of Information Act to get statement any witnesses - including rank-and-file, supervisory and managerial employes - from the National Labor Relations Board at least until the board completes a hearing, the Supreme Court has ruled.

"The danger of witness intimidation is particularly acute with respect to current employes," Justice Thurgood Marshall wrote in the opinion for the court.

"Not only can the employer fire the employe, but job assignments can be switched, hours can be adjusted, wage and salary increased held up and other subtle forms of influence exerted," Marshall said. "A Union can often exercise similar authority over its members and officers."

Three members of the majority foresaw an impact of the decision reaching far beyond the NLRB.The rationale for holding that the FOIA authorizes no "meddling" in NLRB enforcement proceedings "applies equally to any enforcement proceeding," Justice John Paul Stevens wrote in a separate opinion. Chief Justice Warren E. Burger and Justice William H. Rehnquist joined him.

Dissenting in part, Justice Lewis F. Powell Jr., joined by Justice William J. Brennan Jr., agreed that an employer cannot use the FOIA to compel the NLRB to disclose statements by current employes.

But the court went too far, Powell wrote, citing the legislative history of the exemption in the information act for "investigative records compiled for law enforcement purposes, but only to the extent that" disclosure "would interfere with enforcement proceedings."

The decision reversed the 5th U.S. Circuit Court of Appeals in a case in which Robbins Tire & Rubber Co., of Tuscumbia, Ala., sued to force the NLRB to make available - before an unfair labor practice hearing - copies of all statements gathered by board investigators from potential witnesses. The appellate court held that the NLRB could not invoke the investigatory records exemption to withhold the statements.