OPINION OF THE COURT
Section 9(a) of the National Labor Relations Act, as amended (“the Act”), 29 U.S.C. § 159(a),1 requires that a collective bargaining representative be given the opportunity to be present on any occasion when employee grievances are adjusted by the employer. This right, like others in the labor relations field,2 may be relinquished by the employee representative in the give and take of collective bargaining, or at any time when the representative believes that such action *552would be in the best interest of the employees.3 In the present case, the union did execute a limited “waiver” of its rights under § 9(a), and the employer did take action, without the presence of union representatives, which is alleged to have constituted the adjustment of grievances. The question which must be decided is whether the employer’s program can be found to be within the scope of the waiver’s authorization.4
I.
For at least twenty years, Local 12075, United Steelworkers of America, AFL-CIO (“the Union”), and its predecessor have served as the duly designated and recognized collective bargaining representative of certain employees at the Midland Division (Michigan) plants of Dow Chemical Company. The relevant collective bargaining agreement was effective from March 8, 1971 to March 11, 1974.
In December, 1972 the employer instituted a program soliciting communications in the nature of questions, suggestions and complaints from employees. This program, known as “Speak Out,” was begun without prior notice to, or consultation with, the Union. “Speak Out,” was announced by means of a booklet mailed to each employee, which set forth the procedures to be followed and the philosophy and goals of the program:
It opens up a way for any of us to speak his mind, and get an answer, when something’s nagging at us but — for some reason — we’d rather not take it the more usual route.
I’m convinced that ‘Speak Out’ will be a valuable addition to our employee communications.5
Submissions under “Speak Out” were to be made on standard forms and directed to the coordinator of “Speak Out.” The communicating employee had the option of providing his or her name or preserving complete anonymity. Upon receiving a communication, the “Speak Out” coordinator might either deal with it personally or refer it to any other person(s) in management having expertise or authority in the subject matter area. In the latter case, the submitting employee’s name, if shown, would be removed before transmittal. After the “Speak Out” coordinator or other designated company officer(s) had time to gather information, a reply would be composed. However, as the introductory booklet itself made clear, all replies were to be reviewed by the General Manager of the Midland Division; only after that would a reply be sent out to any employee who had signed his “Speak Out” request. In addition, selected responses deemed to be of general interest to employees were published in Brinewell, a monthly employee magazine edited and published by the company, unless the submitting employee requested that the reply not be published.6
Without attempting to categorize the responses to all of the two hundred and *553eighty-four “Speak Out” submissions received between December, 1972 and November, 1973 from members of the collective bargaining unit, we can note that some merely restated and defended company policies, others merely informed that the matter had been referred to specific officers for further investigation, others suggested that the matter be brought to the Union’s attention as a possible topic for future collective bargaining, and still others reflected the granting of some relief from the company action or condition complained of.7
II.
In June, 1973 the Union filed an unfair labor practice charge with the NLRB. The gravamen of the charge was that Dow Chemical, through the “Speak Out” program, had engaged in the adjustment of grievances without permitting the Union the opportunity to be present, in violation of §§ 8(d),8 9(a),9 8(a)(1) and 8(a)(5)10 of the *554NLRA.11 A complaint issued, and thereafter the parties waived hearing and submitted the matter upon stipulated facts and exhibits.
The Administrative Law Judge elected to assume for the purposes of his decision that some of the matters raised in “Speak Out” submissions were grievances, within the meaning of the Act.12 With that assumption, he proceeded to find the remaining elements necessary to bring the employer’s conduct into conflict with § 9(a), including the “adjustment” of some of the matters raised through “Speak Out.” However, the Administrative Law Judge declined to find an unfair labor practice, on the ground that the Union had waived its rights under § 9(a) and related sections of the Act. The finding of waiver was based on the following provision of the then-current collective bargaining agreement:
Article III, Section 3 — Grievance Procedure:
A. It is the intent of this Section, to establish means for prompt adjustment of grievances at the job level with the immediate supervisor and the employee. Therefore, in order to promote better cooperation, understanding, and labor relations between employees, Union Representatives, and the Company, it is agreed that an employee with a complaint or request, must first state his complaint or request to his immediate supervisor, and will give that supervisor a reasonable opportunity to adjust the problem before resorting to grievance procedure. The employee may have a steward present at this meeting, but the employee must state his own complaint.
B. If the complaint is not satisfactorily adjusted by the provisions of Paragraph A, then the grievance procedure outlined below shall be followed. .
(Appendix, p. 45a).
There follows a description of a multi-step grievance mechanism (ending with possible arbitration), with each successive step involving progressively higher levels of company management. The Administrative Law Judge’s crucial determination was that, assuming that grievances had been adjusted in the “Speak Out” program, this involved no variance “of any material significance” (Opinion, p. 875a) from the procedure which the Union had authorized in Section 3A of the collective bargaining agreement.
In December, 1974, a panel of the NLRB adopted without opinion the recommended order of the Administrative Law Judge, and ordered the complaint dismissed (215 NLRB No. 139). One member dissented, taking the position that there were indeed “material difference[s]” (dissenting opinion, p. 886a) between the “Speak Out” procedure and the procedure envisioned by the collective bargaining agreement, and that as a result the former could not be found to be authorized by union consent. From the order of the Board majority the Union petitions this court for review. Dow Chemical Company has intervened.13
*555III.
At the outset we are faced with the question of the proper standard of review. As noted, the parties have stipulated the historical facts;14 in our view the disposition here must depend upon the correctness of the determination that there is no material difference between the contractual procedure and the “Speak Out” procedure. While this might be deemed a question of ultimate fact, or a mixed question of law and fact, we recognize that its resolution is entitled to some deference because the subject matter is within the Board’s area of special expertise. Nevertheless, we are convinced that the view of the dissenting Board member must prevail.
We start from the principle that a waiver of a statutory right must be clearly and unmistakably established, and that express language will not be read expansively. Radio Television Technical School, Inc. v. NLRB, 488 F.2d 457 (3d Cir. 1973); Texaco, Inc. v. NLRB, 462 F.2d 812 (3d Cir. 1972). From this viewpoint we have little difficulty in defining the scope of the union’s waiver. The Union and the Company evidently agreed that an employee would be required initially to state his grievance to his immediate supervisor in a face-to-face meeting.15 If the supervisor was able to satisfy the employee, no further action would be necessary; if not, the formal grievance mechanism would then be available. The parties to the collective bargaining agreement could well have believed that a provision such as Section 3A would be useful in minimizing unwarranted resort to the grievance mechanism by “weeding out” those complaints resulting from simple misunderstanding or oversight, as well as those so trivial that the employee would be unwilling to make an initial statement of his own case to his immediate superior.
The more difficult task is the assessment of the differences between the two programs. In undertaking this task, the Administrative Law Judge focused exclusively on asserted disparities in the degree of involvement of middle and upper management. Certainly there would seem to be differences in this regard, since the Section 3A procedure speaks only of resort to the employee’s immediate supervisor, while “Speak Out” guarantees that at least one middle-management figure (the “Speak Out” coordinator)16 and one top-management figure (the General Manager)17 would see and consider the complaint. The Administrative Law Judge discounted this factor; he stated that, “in practice, ‘Speak Out’ complaints appear to be referred by the coordinator to the supervision involved.” However, this observation is not supported by any reference to the record, and we have been unable to find any evidence that any “Speak Out” submission, let alone all of them, was in fact referred to the immediate supervisor.
In this court, the Board makes a similarly unpersuasive attempt to minimize the difference in the higher management input factor. The Board argues that Section 3A also permits the immediate supervisor to consult with his superiors before responding to the employee. Certainly there is nothing *556in Section 3A which expressly precludes this, but there is also no indication in the record as to the extent, if any, to which this consultation actually occurs.
We are thus unable to agree that this factor may be disregarded. The Board has demonstrated that the two procedures might theoretically operate in the same way in a particular case; however, in the absence of evidence as to how the systems actually work, it is at least equally plausible to theorize that immediate supervisors will never pass Section 3A complaints on to higher officials, and that the “Speak Out” coordinator will never rely on a solution offered by the immediate supervisor. Where the employer seeks to rely on a waiver to justify conduct otherwise prohibited by the Act, we believe that he must provide more than a theory of possible congruence between authorized and actual conduct.
There are other differences between the procedures, not dealt with in the Administrative Law Judge’s opinion, which we believe require consideration.
One is the question of timing. The contractual resort to the immediate supervisor must take place before the grievance procedure begins. The “Speak Out” mechanism would be available to an employee before, during or after institution of a formal grievance; there is no indication that the employer has provided safeguards against parallel adjustments of the same grievance under the contract and under “Speak Out.” This makes it considerably more difficult to argue that “Speak Out” is no more than a substitute for and the equivalent of the pre-grievance “complaint” of Section 3A.18
Another distinguishing factor is the degree to which anonymity may be preserved. Whether or not Section 3A contemplates a face-to-face confrontation,19 the contractual remedy rather clearly contemplates that the complaining employee’s identity will be known to the immediate supervisor, and there is no reason to believe that it would be concealed from any other officials whom the supervisor might contact. “Speak Out,” on the other hand, automatically conceals the employee’s identity from all management personnel except the program co-ordinator, and permits the employee to proceed in complete anonymity.
We also believe that the publication of selected “Speak Out” inquiries and replies in the company magazine is of significance. Once again, there may be nothing in Section 3A to make it clear that the employer could not similarly report the results of pre-grievance complaints presented to immediate supervisors, but there is nothing in the record to indicate that this had ever been done, and we would not intuitively think such a practice likely.
We believe that the foregoing differences in actual or likely operation between the “Speak Out” system and the pre-grievance provision of Section 3A, when considered together, are sufficiently “material” that a consent to the latter cannot be said to authorize the former.20 In so holding, we *557would emphasize three potential effects on the Union’s role as collective bargaining agent, flowing from the operative differences. First, as noted, the “Speak Out” procedure may increase the likelihood that a particular grievance issue will be considered and decided by middle and upper management before the Union’s position is heard, or before the Union even has notice of the dispute. The parties have presented arguments in this court as to whether or not such decisions would be binding precedent in later grievance proceedings and arbitrations as the “common law of the contract.” We do not find it necessary to decide that question, since we believe that at the very least the “ex parte” decision would have some practical and psychological effect were management personnel called upon to take a position on the sale issue in a subsequent grievance hearing. The Union can properly complain of being forced to argue that a position of the employer, previously expressed in a “Speak Out” reply and thereby concurred in by the highest officer involved in the grievance procedure, should be disregarded in a grievance hearing.
Secondly, “Speak Out” replies may well take on greater impact, as compared to a response from an immediate supervisor, in determining whether the complaining employee will follow through with a formal grievance and whether other employees will pursue similar claims. Once again, one reason is that the “Speak Out” reply is more likely to rely expressly on the views of someone in upper management; furthermore, it carries the approval of the General Manager of the Division. Where the employer chooses to publish a reply in the Brinewell, the impact will be broadened as well as deepened. Even if a potential grievant understands that an unfavorable reply states only the employer’s position as to rights and duties under the contract, and that the ultimate determination may be made by an arbitrator or a court, he may still be deterred by the advance knowledge that he is likely to meet opposition at all stages of the grievance process.
Finally, the “Speak Out” system offers flexibilities of time and source of relief which not only are not contemplated by Section 3A, but could further reduce the Union’s ability to plan the processing of grievances in an orderly and internally consistent manner. Especially where a particular dispute may affect a number of employees, the Union retains a legitimate interest, limited only by the first proviso of § 9(a) of the Act once the contractual grievance procedure is begun, in following a grievance to a definitive determination without unpredictable diversions of the type possible under “Speak Out.”
IV.
We believe that our conclusion that “Speak Out” was not authorized by Section 3A of the collective bargaining agreement is fully consistent with the Company’s initial approach to “Speak Out.” The introductory brochure seems to anticipate that the new system would function to transmit information and state complaints, but not to resolve them. There is no direct reference in the brochure to Section 3A, any other part of the collective bargaining agreement, the Union, or the formal grievance procedure.21 Furthermore, the Com*558pany did not originally argue “waiver” under Section 3A before the Administrative Law Judge; its principal position22 was that the system had not been used for the adjustment of grievances within the meaning of the Act.
In any case, we have no occasion to disturb the Administrative Law Judge’s finding that the employer did not implement the “Speak Out” program with any actual intent to undermine the grievance procedure, or any other aspect of protected union activity.
The Company endeavored to show that not only was there no intent to avoid its duty to deal with the Union, there was no such result. We do not question the figures purporting to demonstrate that grievance activity did not decline after “Speak Out” began. (Appendix, pp. 859-61a). However, this demonstration alone is of very little probative value in assessing the materiality of the differences between the pre-existing contractual procedure and “Speak Out.” Many other factors might affect the filing of grievances, and the record does not indicate whether any changes took place in the type of grievance filed or the Union’s rate of success. To the extent that the grievance data is put forward as an argument that “Speak Out,” though perhaps not justified by the Union’s waiver in Section 3A of the collective bargaining agreement, should be permitted to continue because it has done no harm to the Union, the argument must be rejected. When Congress, acting within constitutional limits, determines that possible adverse consequences justify the prohibition of certain conduct, a finding that such consequences have occurred or are likely to occur in a particular situation is not necessary to a conclusion that the statutory prohibition has been violated.
This general principle applies with particular force in the present case, since the Congressional enactment is aimed at a specific type of situation and is based on articulated concerns. That § 9(a) represents a delicate and hotly contested balance between competing policy interests is amply demonstrated by the legislative history. On the one hand, Congress wished to preserve for the employee and the employer some flexibility in dealing with individual problems where the intervention of the union might be unnecessary or counterproductive. On the other hand, Congress recognized that the employer could abuse this flexibility by 1) discriminating between employees on the basis of their support or non-support of the union, 2) taking inconsistent positions with respect to similar claims pressed by different employees, thereby obscuring rights under the collective bargaining agreement, and 3) attempting to create the impression among employees that a “better deal” could be had by not resorting to the union’s representation or mechanisms.23 There is nothing in the *559record to demonstrate that “Speak Out” could not be subject to such abuses.
The Administrative Law Judge in his opinion, and the Board and employer in this court, have expressed the belief that programs like “Speak Out” constitute an innovation beneficial to the Union and employees as well as the employer in promoting efficiency, harmony and understanding.24 Presumably the suggestion is that if we agree, we should refrain from finding that the employer has violated the Act. We must reject this appeal as directed to the wrong forum. Congress has spoken specifically and after due deliberation; neither the Board nor this court has any authority to engraft onto the statutory provision an exception or exemption based on a re-evaluation of policy factors.25
Furthermore, we do not view today’s decision as foreclosing the implementation of programs having the virtues claimed for “Speak Out.”26 Aside from the possibility of Congressional reconsideration of § 9(a), there are at least two options available. First, the parties could negotiate a new “waiver” section of the collective bargaining agreement which, unlike Section 3A, would be broad enough in scope to cover the “Speak Out” program as currently constituted. If the program does indeed offer advantages to all concerned, the negotiation task should not be impossible, at least if appropriate safeguards can be supplied. Furthermore, if, as suggested earlier, the Company originally conceived of “Speak Out” as dealing only with non-grievance (“informational”) matters, it should be feasible to achieve this more limited purpose by preliminarily screening out those “Speak Out” submissions considered to raise grievances, within the meaning of the Act. There could then be no problem under § 9(a).
V.
The preceding sections have treated the petition for review under the assumption that some of the matters adjusted through “Speak Out” were “grievances,” within the meaning of the Act. While counsel for the Board all but conceded at oral argument that this was in fact the case, we agree with petitioner27 that since the Board made no findings on this point, the proper course is to remand to the Board for that determination.
For the foregoing reasons, the petition for review is granted, the order of the National Labor Relations Board dismissing the complaint is vacated, and the case is remanded to the Board for further proceedings consistent with this opinion.