Opinion for the Court filed by Circuit Judge GARLAND.
Wayneview Care Center and Victoria Health Care Center petition for review of a decision and order of the National Labor Relations Board, and the Board eross-applies for enforcement. The Board found, among other things, that the petitioners violated the National Labor Relations Act by implementing new terms and conditions of employment before reaching a lawful impasse in collective bargaining negotiations. Because substantial evidence supports the Board’s findings, we deny the petition for review and grant the Board’s cross-application for enforcement.
I
Wayneview and Victoria, separate companies that share ownership, operate nursing homes in New Jersey. SEIU 1199, New Jersey Health Care Union, represents the certified nursing assistants and housekeeping, laundry, and dietary employees at both facilities. In 2005, Wayne-view and Victoria had separate contracts with the union due to expire on March 31 of that year. In February 2005, the parties began to negotiate successor contracts. The union initially negotiated with each employer separately, but after several meetings, the parties agreed to consolidate negotiations. Justin Foley was the first chief negotiator for the union. Vincent Tufariello, the chief operating officer of both Wayneview and Victoria, was the chief spokesman for the employers.
The union made its first full economic proposal on May 10, 2005. It called for an annual wage increase of 4% for three years, more paid days off, and a decrease *345 in work hours at Victoria. Under the proposal, the employers would participate in the union’s own health insurance plan, with a contribution rate of 22.33% set by the plan’s trustees. There was also a new formula to set the amount of pension contributions. Finally, the union sought a gradual reduction in the number of “no-frills” employees (employees who could choose higher wages in lieu of benefits).
The parties continued to meet and bargain over the following months. In July, the union assigned Foley to another position, and Larry Alcoff took over as the union’s lead negotiator. He met with Tufariello for the first time on August 5, 2005, and presented a new proposal. That proposal contained some concessions: The union dropped its demand for a reduced work week, reduced its pension proposal, and delayed the start-date for participation in the union’s health insurance plan. Although there was tentative agreement on some items, including wages for certain classes of employees, other items remained unresolved. When the parties met again on August 9, Tufariello told Alcoff that the two principal stumbling blocks in the way of a collective bargaining agreement were the union’s proposals regarding no-frills employees and health insurance.
The parties convened on Thursday, August 18 for a “marathon” bargaining session that lasted until 3 a.m. the following day. Hr’g Tr. 242 (Sept. 27, 2006) (J.A. 95). At that session, which two mediators also attended, the union presented another new proposal containing several significant concessions. First, its proposal regarding wages no longer had specific dates and percentages for increases; instead, it had only a general target to be reached by the end of the contract term. Second, the union changed its health insurance proposal. For the first time, it abandoned its demand that the employers participate in the union’s health plan and agreed that employees could be covered by the employers’ existing plan. Finally, the union dropped its proposal to decrease the number of no-frills employees. Thus, the union softened its position on the specific items that Tufariello had identified as the major obstacles to an agreement.
The employers’ counterproposal also contained significant concessions. Alcoff felt that the August 19 session provided “a roadmap to a deal,” Hr’g Tr. 243 (Sept. 27, 2006) (J.A. 95), and union president Milly Silva agreed that it was “probably the most productive” that had taken place, Hr’g Tr. 135 (Sept. 26, 2006) (J.A. 71). Alcoff gave his cell phone number to the mediator and employers’ counsel so that negotiations could continue over the weekend. He did not hear back, however, until Monday evening, August 22. That night, the employers faxed a regressive proposal — which they later claimed to be their “last best offer” — and refused to bargain further. On September 6, or soon thereafter, the employers implemented the terms of that offer. Letter from Dennis Alessi to Larry Alcoff (Oct. 3, 2005) (J.A. 405).
Meanwhile, the union was preparing for concerted action at Wayneview and Victoria. On August 12, the union had sent statutorily required, ten-day notices to both facilities, see 29 U.S.C. § 158(g), stating that its members would engage in a “strike, picketing, or other concerted refusal to work” starting on August 23. Letter from Milly Silva to Margaret Nolan (Aug. 12, 2005) (J.A. 306); Letter from Silva to Michael Del Sordo (Aug. 12, 2005) (J.A. 307). In response, the facilities lined up potential replacements. But Nolan told the replacements that they might never work at all and that the permanent employees could return at any time. Hr’g Tr. 889 (Dec. 4, 2006) (J.A. 200).
*346 At Wayneview, the employees ultimately voted not to strike. Silva notified Wayne-view by fax on August 22 that the employees would only engage in after-hours informational picketing, and that they intended to work their regular schedules. Fax from Silva to Tufariello (Aug. 22, 2005) (J.A. 312). Wayneview replied through counsel that, since it had already lined up temporary replacements, “there is no work for your members at Wayne[v]iew. Please advise your members not to report to work tomorrow morning.” Fax from Alessi to Silva (Aug. 22, 2005) (J.A. 313). Employees who showed up on or after August 23 were not permitted to work. One employee who attempted to return, Margaly Pierre, was told that if she wanted to work at Wayneview, she “was to sign” a paper “to vote the union out.” Hr’g Tr. 506-07 (Oct. 19, 2006) (J.A. 145).
At Victoria, the employees voted to strike for five days. They went on strike on August 23, and then, in a letter dated August 26, “unconditionally offer[ed] to return to work” on August 28. Fax from Alcoff to Del Sordo (Aug. 26, 2005) (J.A. 314). Victoria replied that employees would be allowed to work only if the union accepted the regressive offer faxed by the employer on August 22. Fax from Alessi to Alcoff (Aug. 26, 2005) (J.A. 315). Victoria further warned that, starting on September 6, it would unilaterally implement the August 22 offer and permanently replace striking workers. Id. As at Wayne-view, Victoria did not permit its employees to work on August 28; instead, a supervisor informed them, “It’s a lockout.” Hr’g Tr. 53 (Sept. 26, 2006) (J.A. 54).
The union filed four unfair labor practice charges against Wayneview and Victoria between July 1, 2005 and April 12, 2006. Thereafter, the NLRB’s General Counsel issued a consolidated complaint. On July 26, 2007, an administrative law judge (ALJ) concluded that the employers had committed several unfair labor practices in violation of the National Labor Relations Act (NLRA), 29 U.S.C. § 151
et seq. Wayneview Care Ctr.,
The Board agreed with the ALJ that the employers failed to prove the parties had reached a lawful impasse, and that the employers violated the NLRA by implementing their August 22 offer without first having reached such an impasse.
Wayneview,
II
Section 10(e) of the NLRA provides that “[n]o objection that has not
*347
been urged before the Board ... shall be considered by the court, unless the failure or neglect to urge such objection shall be excused because of extraordinary circumstances.” 29 U.S.C. § 160(e);
see Woelke & Romero Framing, Inc. v. NLRB,
In addition, although they apparently did object below, the petitioners do not contest here that each of them violated the NLRA by refusing to provide the union with information relevant to bargaining and by refusing to meet with the union following the August 22 proposal. The Board is therefore also entitled to summary enforcement of the portions of its order relating to those violations.
Bally’s Park Place, Inc. v. NLRB,
Ill
The petitioners do contest the Board’s determination that they violated section 8(a)(5) and (1) of the NLRA, 29 U.S.C. § 158(a)(5) & (1), by unilaterally implementing their August 22 offer in the absence of a lawful impasse. Section 8(a)(5) of the Act makes it an unfair labor practice for an employer “to refuse to bargain collectively with the representatives of his employees.”
Id.
§ 158(a)(5). “An employer violates this duty to bargain if, absent a final agreement or a bargaining impasse, he unilaterally imposes changes in the terms and conditions of employment.”
TruServ Corp. v. NLRB,
As we have noted many times before, our role in reviewing an NLRB decision is limited. “We must uphold the judgment of the Board unless, upon reviewing the record as a whole, we conclude that the Board’s findings are not supported by substantial evidence, or that the Board acted arbitrarily or otherwise erred in applying established law to the facts of the case.”
Mohave Elec. Coop., Inc. v. NLRB,
The Board’s determination that the petitioners failed to prove that the parties had reached impasse easily satisfies our deferential standard of review. The petitioners declared impasse soon after the marathon bargaining session of August 18-19.
See Wayneview,
The petitioners argue that, appearances aside, the union bargained in bad faith because it adhered rigidly to the terms of another contract — known as the “Tuchman Agreement” — that it had recently negotiated with other nursing facilities. The Tuchman Agreement contained
*349
a “most-favored nations” clause, and the petitioners contend the union regarded itself as bound to the terms of that agreement. Although it is true that some of the terms of the union’s initial proposal resembled those of the Tuchman Agreement, that proposal also differed in several respects, including with regard to wages and paid time off.
The principal support for the employers’ contention that the union acted in bad faith is the testimony of three witnesses, who claimed that the union was unwilling to negotiate variances from the Tuchman Agreement. But the ALJ expressly discredited all three of those witnesses. “ ‘[W]e do not reverse the Board’s adoption of an ALJ’s credibility determinations unless ... those determinations are hopelessly incredible, self-contradictory, or patently unsupportable.’ ”
United Food & Commercial Workers Union Local 204 v. NLRB,
The petitioners also contend that Foley, the union’s first negotiator and a witness whom the ALJ did credit, admitted in his testimony that his superior, Alcoff, “surreptitiously controlled the negotiations and would not allow the Union’s bargaining representatives to unilaterally accept any terms that deviated from the standard Union proposals set forth in the [Tuchman] Agreement.” Pet’r Reply Br. 6. But nothing in Foley’s testimony supports this contention. Foley did say that Silva (the union’s president) “was working with ... Larry Alcoff in coordinating most of how the overall contract negotiations were going,” Hr’g Tr. 1099 (Dec. 6, 2005) (J.A. 233), but he did not suggest that Alcoff or Silva told him not to deviate from the Tuchman Agreement. In fact, when Foley was expressly asked during cross-examination whether “there [was] any requirement that ... the contracts for Victoria or Wayneview needed to mimic the language or terms of the Tuchman Agreement,” or whether “anyone ever suggested]” that they should, Foley replied, “No.” Id. at 1115-16 (J.A. 237).
Finally, the petitioners assert that, notwithstanding progress on other issues, the parties ultimately deadlocked over the single critical issue of health insurance, which led to a complete impasse. Although under certain circumstances deadlock on a single issue can justify an overall finding of impasse,
see Dallas Gen. Drivers v. NLRB,
The petitioners have not made that showing here. Although they claim that the parties were deadlocked over the employers’ participation in the union’s health insurance plan, that claim fails for two reasons. First, the petitioners have not shown that the asserted deadlock over health insurance inhibited progress on any other aspect of the negotiations. And second, the evidence is that there was no deadlock: In the final bargaining session before the petitioners declared impasse, the union let go of its demand that the employer participate in the union’s health insurance plan — the precise issue that the petitioners claim created the impasse.
An employer violates section 8(a)(5) and (1) of the NLRA if it “unilaterally imposes changes in the terms and conditions of employment” before either final agreement or bargaining impasse.
TruServ,
TV
The petitioners also challenge the Board’s determination that they violated section 8(a)(3), (5), and (1) of the NLRA by unlawfully locking out their employees without a “legitimate and substantial business justification,” in an attempt to coerce the union into accepting the employers’ so-called “last best offer” of August 22.
Wayneview,
*351
Substantial evidence supports the Board’s conclusion that the petitioners did just that. During the strike at Victoria, the petitioners’ lawyer sent a fax to Alcoff advising that employees would not be allowed to return to work unless the union accepted the employers’ August 22 offer. Fax from Alessi to Alcoff (Aug. 26, 2005) (J.A. 315). The ALJ reasonably determined that this “refusal to reinstate the strikers after their unconditional offer to return ... constituted a lockout,” that Victoria expressly conditioned the end of its lockout on the union’s acceptance of the August 22 offer, and that “the employer was not entitled to impose a final offer because there was no valid impasse.”
Wayneview,
The petitioners counter that the lockouts were “ ‘defensive’ lockouts] reasonably necessary to ensure continued patient care,”
id.,
and therefore lawful under
Sociedad Española de Auxilio Mutuo y Beneficiencia,
None of those circumstances exists in this case. The ALJ noted that administrator Nolan’s “unreliable and shifting” testimony did not evidence any firm commitment to the replacement workers at Wayneview, or any practical difficulties in notifying them of the union’s decision not to strike.
The petitioners insist that “substantial record evidence established that [they] lawfully locked out their employees for legitimate business reasons.” Pet’r Br. 54. Even if this were a correct assessment of the record, its premise inverts the appropriate standard of review. The question before us is not whether substantial evidence supports the petitioners’ view, but whether it supports the Board’s. See 29 U.S.C. § 160(e) (“The findings of the Board with respect to questions of fact if supported by substantial evidence on the record considered as a whole shall be conclusive.”). Because it does, our inquiry with respect to this violation is concluded.
V-
Finally, the petitioners dispute the Board’s finding that, “[b]y promising employees a return to work and increased benefits if they signed a petition to decertify the Union, ... Wayneview assisted employees in the solicitation of signatures on a petition to decertify the Union in violation of Section 8(a)(1) of the Act.”
Wayneview,
The Board’s finding arose out of two separate allegations in the General Counsel’s complaint. The first involved employee Margaly Pierre, who attempted to return to work at Wayneview during the lockout. According to Pierre’s testimony — which the ALJ credited and no witness contradicted — director of nursing Nancy Ziccone asked her if she wanted to “work with Wayneview” or “work with the Union.” Hr’g Tr. 504-05 (Oct. 19, 2006) (J.A. 145). Pierre replied that she was' a single mother who needed a job and would choose to work.
Id.
at 505. Another supervisor told her that if she agreed to work without the union, she would get “free health benefits, health insurance, free paid vacation, free personal days, and free sick days.”
Id.
at 506. Ziccone then gave Pierre a piece of paper with language to “vote the Union out,” and told her that “if [she] were to work with Wayneview [she] was to sign the paper.”
Id.
at 506-07. She did. The General Counsel’s second allegation involved staffing coordinator Christopher Irizarry, whom the ALJ found had assisted in gathering signatures of locked-out employees on a decertification petition.
Wayneview,
The petitioners’ opening brief does not address Ziccone’s treatment of Pierre at all. Instead, its entire discussion concerns the allegation of misconduct by Irizarry. But that attack is misdirected, because the Board rested its affirmance of the ALJ’s finding solely on the incident involving Pierre. It was “unnecessary to rely on the conduct of Wayneview’s staffing coordinator, Christopher Irizarry,” the Board said, because “[a]n additional violation based on Irizarry’s conduct would be essentially cumulative and would not materially affect the remedy.” 352 NLRB at
*353
1089 n. 3 (Board Op. I). Although the petitioners do finally address the Pierre incident in their reply brief, that argument comes too late.
See N.Y. Rehab. Care Mgmt. v. NLRB,
VI
For the foregoing reasons, we deny the petition for review and grant the Board’s cross-application for enforcement.
So ordered.
Notes
. "An employer who violates section 8(a)(5) also derivatively violates section 8(a)(1), which makes it unlawful for an employer 'to interfere with, restrain, or coerce employees in the exercise of their statutory labor rights."
Regal Cinemas, Inc. v. NLRB,
. The ALJ found one witness unreliable because she "often contradicted herselff] ... could not recall various subjects relating to the bargaining,” and was "not truthful” about her attempts to replace SEIU 1199 with a rival union.
Wayneview,
. Section 8(a)(3) states that it is an unfair labor practice for an employer "by discrimination in regard to hire or tenure of employment or any term or condition of employment to encourage or discourage membership in any labor organization.” 29 U.S.C. § 158(a)(3).
. Although the Supreme Court has held that an employer may lock out its employees "for the sole purpose of bringing economic pressure to bear in support of its legitimate bargaining position,”
Am. Ship Bldg. Co. v. NLRB,
. There is no merit to the petitioners’ contention that the offer to return was not "unconditional” because the strikers refused to accept the terms of the August 22 offer. As the ALJ noted, the terms of the expired contract were still in place when the union went on strike, and the strikers were prepared to return to work on those terms.
