Opinion for the Court filed by Circuit Judge GARLAND.
Mohave Electric Cooperative, Inc. petitions for review of a decision and order of the National Labor Relations Board (NLRB), which concluded that the company unlawfully discharged employee Rich *1186 ard Michaels for protected concerted activity in violation of section 8(a)(1) of the National Labor Relations Act (NLRA), 29 U.S.C. § 158(a)(1). The NLRB cross-petitions for enforcement of its order. We deny the petition for review and grant the cross-petition for enforcement.
I
Mohave is an electric utility operаting out of Bullhead City, Arizona. It has approximately seventy employees, roughly twenty of whom are represented by the International Brotherhood of Electrical Workers, Local 769, AFL-CIO (“the Union”). The bargaining unit consists of linemen, mechanics, warehousemen, and between eight and twelve meter readers. The latter are responsible not only for reading electric meters, but also for meter installation, meter connection and disconnection, and other related duties. Gene Quinn supervises Mohave’s meter department and reports to Tom Longtin, the operations manager.
Consistent with the terms of its collective bargaining agreement (CBA), Mohave uses several subcontractors to supplement its work force. One subcontractor, Guard Force, has provided Mohave with additional meter readers since 1993. Guard Force employees wear uniforms like those of Mohave meter readers, and they work out of the same room on Mohave’s premises. Although they have their own on-site supervisor, David Drabek, he reports to Mohave’s Gene Quinn.
See Mojave Elec. Coop.,
327 N.L.R.B. No. 7,
Richard Michaels worked as a meter reader for Mohave from August 1991 until his termination on June 3, 1996. He was one of two union stewards at the Mohave facility and served on a number of the Union’s committees. His work history was generally uneventful until May 1996.
The parties dispute the details of the events that began that month and that ultimately culminated in Michaels’ discharge. The Administrative Law Judge (ALJ) who heard the case found that on the morning of May 8, Michaels called Drabek, the Guard Force supervisor, to complain that a Guard Force employee had insisted that Michaels trade meter-reading routes for the day. Following that conversation, Drabek reported to Mohave that Michaels had been rude to him. Michaels denied the allegation, and his supervisor, Quinn, ended the matter by finding that Michaels “had acted properly.”
Mojave Elec.,
Later that same month, Michaels learned from a friend that someone wearing a Mohave uniform had been stoppеd at a local grocery store for shoplifting. Pursuant to company policy, Michaels reported this to Quinn, who in turn advised Longtin, Mohave’s operations manager, and Jay Nady, the owner of Guard Force. According to Nady and Longtin, the story that reached them was that Michaels had reported that the person wearing the Mohave uniform was a Guard Force employee, who had been handcuffed and driven away by the police. The actual facts were somewhat less dramatic: there had been no police arrest; the store’s own security force had stopped the Guard Force employee, who claimed to have “forgotten” to pay for an item he took from the store. Nady and Longtin concluded that Michaels had exaggerated the story in order to discredit Guard Force. At the hearing before the ALJ, however, Michaels testified that he had merely reported what he had heard — that someone wearing a Mohave uniform had been stopped for shoplifting— and nothing more. Based on the demean- or of the witnesses, the ALJ found Mi-chaels’ testimony substantially more credible than that of Nady and Longtin. He *1187 therefore credited Michaels’ testimony and concluded that if there had been any exaggeration, it had been by Mohave’s supervisors rather than Michaels.
On May 21, angry about the alleged exaggeration, Nady went to Mohave’s facility “to confront and straighten out Mi-chaels.” Id. at *6 (internal quotation omitted). Unable to find him, Nady instead located Stuart Douglas, another Mohave meter reader whom Nady had often seen with Michaels. Although the parties dispute the detаils of the encounter, it appears that Nady asked Douglas about Mi-chaels’ whereabouts and that there was a brief physical confrontation between them. 2
The next day, when Michaels returned to work, Douglas told him that he had been physically and verbally assaulted by Nady, and that Nady had been “looking for” Michaels when this occurred. Mi-chaels promptly told his supervisor that he felt threatened, and he asked the company for protection. Quinn told him to “give it a couple of days” and took no further action, although later Lоngtin did advise Nady that Mohave “reserved to itself any issues of supervision or discipline of its employees.” Id. at *7. Concerned about their physical safety, Michaels and Douglas met with their coworkers and discussed their options. They described Nady’s alleged assault on Douglas and stated that they were considering turning to the courts for protection. Michaels gave un-contradicted testimony that the other employees agreed with and supported such action. See Tr. at 189-90.
On May 28, in Bullhead City municipal court, Michaels and Douglas filed petitions for injunсtions against harassment, citing their need for protection from “verbal and mental abuse and possibly physical violence” by Nady and Drabek. App. at 139-43. The petitions requested that Nady and Drabek have no contact with Douglas and Michaels, and that they be enjoined to stay away from the petitioners’ homes and place of employment.
On May 29, Nady received copies of the petitions and immediately contacted Long-tin. He told Longtin that, if the injunctions were granted, neither he nor Drabek would be allowed on Mohavе property. This, he said, would prevent them from performing their duties as subcontractors. Thereafter, Longtin decided to terminate Michaels. According to Longtin’s testimony, he did so because Michaels had filed the petition, exaggerated the shoplifting incident, spoken rudely to Drabek in the telephone conversation of May 8, and called Guard Force employees “scabs.”
Mojave Elec.,
The ALJ concluded that the filing of the petitions was protected conduct under the NLRA, and rejected Mohave’s contention that the filing was rendered unprotected because it constituted “disloyalty.” Applying the familiar Wright Line test, 3 the ALJ found that a prima facie violation of section 8(a)(1) had been established because Mohave “admittedly fired [Michaels], at least in part, because of his having filed the petition,” id. at *11, and because Mohave did not show that it would have firеd Mi-chaels in the absence of that protected conduct, see id. at *9-11. The NLRB affirmed. 4 Thereafter, Mohave petitioned *1188 this court for review, and the Board cross-petitioned for enforcement.
II
As we have noted many times before, our role in reviewing an NLRB decision is limited.
See, e.g., Pioneer Hotel, Inc. v. NLRB,
Mohave seeks to overturn the Board’s finding that it committed an unfair labor practice on two principal grounds. First, it contends that Michaels’ conduct in filing the injunction petition was unprotected because it was “disloyal.” Second, it contends that Michaels’ activity was unprotected because it was inconsistent with the collective bargaining agreement. In addition, Mohave argues that even if it did discharge Michaels for protected activity, the remedy should be limited because the company would have fired him in any event based on evidence of unrelated misconduct it discovered after his termination. 5 We consider each of these arguments below.
A
Section 7 of the NLRA guarantees employees the “right to self-orgаnization, to form, join, or assist labor organizations, ... and to engage in other concerted activities for the' purpose of collective bargaining or other mutual aid or protection.” 29 U.S.C. § 157. Section 8(a)(1) of the Act implements that guarantee by declaring that “[i]t shall be an unfair labor practice for an employer ... to interfere with, restrain, or coerce employees in the exercise of the rights guaranteed in [section 7].”
Id.
§ 158(a)(1);
see PHT, Inc. v. NLRB,
Mohave does not dispute the ALJ’s conclusion that the filing of a judicial petition — supported by fellow employees and joined by a co-employee — constitutes concerted action under the NLRA. 6 Nor does Mohave dispute that concerted action to ensure greater workplace safety through petitioning for injunctive relief may constitute protected conduct. Instead, it contends that Michaels’ conduct was unprotected here because it was “disloyal,” in that if granted, the injunction would have interfered with the business relationship between Mohave and Guard Force.
It is true that an employer may discharge an employee for disloyalty without committing an unfair labor practice.
7
But the fact that an employee’s actions may cause some harm to the employer does not alone render them disloyal.
See NLRB v. Knuth Bros., Inc.,
Mohave contends that Michaels’ petition was in fact filed “with malice and in bad faith” because it was intended not to protect employees but rather to disrupt Mohave’s relationship with Guard Force. Mohave Br. at 19. The ALJ, however, found to the contrary, and we affirm that finding as supported by substantial evidence. As the ALJ stated, “whether or not one regards Michaels’ fears as totally realistic,” it is not possible to conclude that they were baseless.
Mojave Elec.,
The ALJ’s observations are fully supported by Michaels’ testimony, which the ALJ found to be of “superior” credibility— a determination to which we defer. Mi-chaels testified without contradiction that he “felt very threatened” when he hеard Nady had come looking for him, that he felt “the physical altercation between [Nady] and Douglas was actually directed towards [him],” and that he and Douglas filed their petitions to protect themselves from further harassment. Tr. at 184-90. Mohave officials conceded that Michaels communicated his safety concerns to the company both before and after the petitions were filed,
see id.
at 92-93, 337, and that he asked the company to take “some action to protect” him,
id.
at 85 — a request Mohave initially put off with the suggestion tо “give it a couple of days,”
Mojave Elec.,
Mohave contends that the filing of the petitions should not be considered in isolation, and that Michaels’ bad faith is evidenced by the fact that the filing was part of a long-term campaign to discredit Guard Force and sever its contractual relationship with Mohave. Other elements of this asserted сampaign were Michaels’ alleged exaggeration of the shoplifting incident, his allegedly rude telephone conversation with Drabek on May 8, his purported practice of calling Guard Force employees “scabs,” and the fact that after the May 21 incident with Nady, Michaels filed a union grievance seeking the removal of Guard Force from Mohave’s property. The ALJ readily disposed of each of these claims,
see Mojave Elec.,
We conclude that substantial evidence supports the Board’s finding that Michaels did not file his petition out of bad faith or malice. Accordingly, we reject Mohave’s contention that Michaels’ conduct was “disloyal” and therefore unworthy of NLRA protection.
B
Mohave also contends that the filing of Michaels’ judicial petition was unprotected because it was “contrary to the express terms of the collective bargaining agreement between [Mohave] and Mi-chaels’ union.” Mohave Br. at 20. That agreement, the compаny argues, not only “permit[ted] [Mohave] to contract with Guard Force, it specifically prohibited Mi-chaels from interfering with that and other aspects of [Mohave’s] operations.” Id. at 20-21. Thus, the company contends, by seeking an injunction that would have impaired Guard Force’s ability to fulfill its contract with Mohave, Michaels breached the CBA.
Mohave is correct that conduct in breach of a collective bargaining agreement is one of “the normal categories of
*1191
unprotected concerted activities.”
NLRB v. Washington Aluminum Co.,
It is doubtful that a collective bargaining agreement could waive an employee’s statutory rights
10
in the manner claimed by Mohave.
11
But even if this were the kind of right that a CBA could waive, the Supreme Court has held that such a waiver must be “clear and unmistakable.”
Wright v. Universal Maritime Serv. Corp.,
Nothing in the collective bargaining agreement at issue here even approaches this “clear and unmistakable” standard for waiver. The provision upon which Mohave relies bears the title “NO STRIKE” and reads as follows:
During the terms of this Agreement, under no circumstances will the Union or the employees engage in, instigate, cause, permit, encourage, or take part in any strike, boycott, work stoppage, slowdown, cessation of work, interruption of work, sympathy strike, unfair labor practice strike, picket, curtailment of work, reduction of production, or interference of any kind with the operations of the Employer.
App. at 123 (emphasis added). As is immediately apparent, the provision does not mention the exercise of statutory rights or the filing of lawsuits at all. Rather, as its title makes clear, it is principally a no-strike provision, and the specific prohibitions it sets forth are all against work stoppages of one form or another. Although Mohave contends that the phrase we have italicized above, “or interference of any kind,” gives the prohibition a wider scope, the canon of ejusdem generis (“of the same kind or class”) counsels against our reading that general phrase to include conduct wholly unlike that specified in the *1192 immediately preceding list of prohibited acts. In any event, given the Supreme Court’s admonition that we should not infer waivers of statutory rights unless they are “clear and unmistakable,” we see nothing in this CBA to justify inferring a waiver of the proportiоns claimed by Mohave. 12
C
Having rejected Mohave’s arguments that Michaels’ conduct was unprotected, we turn now to its alternative argument: that evidence acquired after Michaels’ termination should limit his remedy. The NLRB awarded Michaels full reinstatement and backpay from the time of his discharge.
See Mojave Elec.,
To preclude reinstatement and limit backpay on the basis of after-acquired evidence, the employer has the burden of proving that the evidence reveals misconduсt for which it
“would
have discharged any employee,” not simply for which it
could
have done so.
Marshall Durbin Poultry Co.,
There is such substantial evidence here. The ALJ concluded that “even if [he] had found the events to have occurred as testified to by Bauguess,”
14
he could not credit Longtin’s testimony that this kind of misconduct would alone have resulted in Mi-chaels’ discharge.
Mojave Elec.,
The inference drawn by the ALJ is a reasonable one.
See John Cuneo, Inc.,
Ill
For the foregoing reasons, Mohave’s petition fоr review is denied, and the Board’s cross-petition for enforcement is granted.
So ordered.
Notes
. Although the Board employs the spelling "Mojave,” we use the spelling employed by the petitioner in this court.
. Douglas claimed “that he’d been physically and verbally assaulted by Nady, with Nady grabbing him by the shirt and shaking him.”
Mojave Elec.,
.
See Wright Line,
.The ALJ also concluded that Michaels had been discharged because of anti-union animus in violation of NLRA § 8(a)(3), 29 U.S.C. § 158(a)(3). In light of its conclusion that Miсhaels was unlawfully discharged in viola
*1188
tion of section 8(a)(1) for filing the civil injunction petition, the Board found "no need to rely on the judge’s conclusion that the discharge also violated Section 8(a)(3)."
Mojave Elec.,
. In the Statement of Facts section of its brief, Mohave suggests that Michaels was not fired solely for the filing of the petition, but rather due to a continuing "pattern” of disloyal actions including, inter alia, exaggerating the shoplifting incident, speaking rudely to Dra-bek, and calling Guard Force employees names.
See
Mohave Br. at 5-6;
see also id.
at 14. Even if this were true, there is substantial evidence to support the ALJ’s conclusion that Mohave failed to overcome its
Wright Line
burden of showing it would have fired Michaels absent the filing of the petition.
See Transportation Management Corp.,
.
See, e.g., Prill,
.
See, e.g., NLRB v. Local Union No. 1229,
.
Accord Leviton Mfg. Co. v. NLRB,
.
See Walls Mfg. Co.,
. Michaels’ petition was based on Ariz.Rev. Slat. § 12-1809, which authorizes courts to grant injunctions against harassment.
.
See Barrentine v. Arkansas-Best Freight Sys., Inc.,
. This case is therefore completely different from
Emporium Capwell Co. v. Western Addition Community Org.,
.
Cf. McKennon v. Nashville Banner Publishing Co.,
.The ALJ also concluded that the alleged payment to Bauguess had not been made, stating that Michaels denied he had ever paid anyone to take his meter route.
See Mojave Elec.,
. Although Bauguess was technically an employee of Guard Force rather than Mohave, Mohave exercised ultimate supervision over all meter readers. See Tr. at 269-70. Long-tin specifically testified that he could demand the discharge of a Guard Force employee for misconduct. See id. at 365-66.
