The question presented is whether the Freedom of Information Act (FOIA), 5 U. S. C. § 552 (1976 ed.), requires the National Labor Relations Board to disclose, prior to its hearing on an unfair labor practice complaint, statements of witnesses whom the Board intends to call at the hearing. Resolution of this question depends on whether production of the material prior to the hearing would "interfere with enforcement proceedings" within the meaning of Exemption 7 (A) of FOIA, 5 U. S. C. § 552 (b) (7) (A) (1976 ed.).