SEYMOUR, Circuit Judge.
Petitioner YMCA of the Pikes Peak Region, Inc., challenges a National Labor Relations Board order adopting the Administrative Law Judge’s ruling that the YMCA violated sections 8(a)(1), (3), and (4) of the National Labor Relations Act, 29 U.S.C. §§ 158(a)(1), (3), and (4) (1988). The Board filed a cross-application for enforcement of the order. We have reviewed the arguments of the YMCA, and we hold that enforcement of the Board order is warranted.
I.
The YMCA of the Pikes Peak Region is a nonprofit, charitable, membership organization with two branches in Colorado Springs, a Downtown Center and a Garden Ranch Center. These facilities offer swimming pools, exercise equipment, weight rooms, tanning beds, meeting areas, and locker rooms, some of which are equipped with saunas, whirlpools, color television, and free toiletries and towels. The YMCA provides a range of health, educational, and recreational programs for children, adults, and senior citizens, including swimming instruction, yoga, aerobics, karate, weight reduction, and smoking cessation programs. The two facilities have a membership of approximately ten thousand.
Each member of the YMCA receives a card which has a statement of purpose on the back reading in part: “ ‘The purpose of the Y ... is to establish and maintain a fellowship of individuals and families of all faiths, and ... build a Christian society through activities and services which con[1445]*1445tribute to spiritual, intellectual, physical and social growth.’ ” Rec., vol. I, at 52.
The YMCA’s membership dues and program fees constitute its principal source of income. During calendar year 1986, its gross revenues were $2,674,500, of which $56,700 went to purchase supplies and materials directly from suppliers located outside the State of Colorado. See rec., vol. II, g.c. ex. 2. The YMCA of the Pikes Peak Region is affiliated with the YMCA of the U.S.A., to which the local YMCA pays a percentage of its income in exchange for use of the logo, an employee retirement fund, and a number of other services. Local YMCAs must follow the constitution of the national YMCA, but their national affiliation does not require that they honor memberships from locations outside Colorado.
The YMCA’s Garden Ranch Center first hired Rita Ague in July, 1985, to work as a substitute on the aquatic staff. In September, she began working twenty hours a week on a regularly scheduled part-time basis. On October 6, during an informal meeting called by aquatic director Diane Sanford and consisting of the entire aquatic staff, Ague voiced concerns she and other employees held about pool safety, wage, and overtime pay problems. Ague suggested to those at the meeting that because of these concerns, the employees might want to consider bringing in a union, and she passed around an envelope for interested employees to sign. Ague and four other employees put down their names. Ague then contacted the Office and Professional Employees Union, Local No. 5.
The next day, Sanford and Fawn Kirkland, Ague’s immediate supervisor, reported to Ray Weber, the Garden Ranch Center executive director, that Ague had circulated the sign-up sheet. On October 8, Weber approached Ague while she was working in the pool area and asked her to come into his office. With Sanford present, Weber expressed his concern that Ague had not come to him first with the problems she saw at the YMCA. According to Ague, Weber then asked her whether she had contacted the union, and when she said that she had, he asked her what specific person she had contacted. He also requested that Ague inform him of “any union activities that might be occurring, or would occur in the future.” Rec., vol. I, at 88. At some point in the conversation, they discussed the termination of an employee, whom Ague believed was fired for his union activities, but whom Weber asserted had resigned voluntarily. Within a few weeks of Ague’s conversation with Weber, YMCA employees and a union representative began to meet.
On October 14, Fawn Kirkland telephoned Ague to inform her that her hours “had been cut way back.” Id. at 91. Kirkland told her that there had, not been any problem with her work performance, but that Sanford had told Kirkland that Ague’s “hours were being cut back radically and that Ray Weber wanted to get rid of the troublemaker.” Id. at 92. Kirkland also told her that she had recently submitted her own resignation.
Ague confronted Sanford, who denied making the “troublemaker” comment. Ague informed her that she intended to contact the union regarding her hours change, and she did so. According to Ague, Sanford then told her that “she was still in the process of reshuffling [the schedule], and she would get back to [Ague].” Id. at 94. The union sent the YMCA a letter dated October 24 expressing its intent to organize the YMCA workers, and noting that any change in Ague’s working conditions as a result of her organizing activities would violate section 8(a)(3) of the Act. See rec., vol. II, r. ex. 7. By the end of October, Ague’s hours essentially had been restored.
On November 13 and 14, James Klever, the YMCA’s president and chief executive officer, conducted mandatory meetings for all employees in order to discuss the current unionization efforts. At one point during a meeting at which Ague was present, Klever commented that “it took a hundred men to build a barn, but one jack[1446]*1446ass to tear it down.” Rec., vol. I, at 98.1 When Klever opened up the meeting for general discussion, Ague stood up and explained that she was the “jackass” referred to because she was the person who had called the union. She then elaborated upon the reasons why she thought a union was necessary.
At a later meeting with Klever, Ague again stood up to explain why she favored unionization. She also stated her concern that “when employees had tried to organize ... they had been asked to resign.” Id. at 102. According to Ague, Klever then told her that “ ‘[i]f you knew what a limb you’ve climbed out onto, you’d have heart failure.’ ” Id. She replied, “ T don't threaten easily,’ ” and Klever responded, “ ‘Neither do I.’ ” Id. at 102-03.
During this time, efforts to organize the employees continued. One of the union activists, Bernadette O’Bryan, had a conversation about unionization with co-employee Dennis Schwed on November 15 while both were working in the physical services area. O’Bryan testified that she had asked Schwed, who is mildly retarded and has emotional problems, what he thought of the meetings concerning union organization efforts. He told her he wanted to talk to a friend about unions. O’Bryan suggested he also might want to talk to YMCA employees, and then she. mentioned she felt “really frustrated with the narrow-mindedness of the employees that have come to [her] over the years complaining about different policies at the Y and then not doing anything about it.” Id. at 222.
About a week later, O’Bryan’s supervisor, Jim Asleson, called O’Bryan into his office and handed her a letter. The letter was a warning to her that any similar discussion regarding union matters would result in her termination. Asleson told her that Schwed had been very upset after the conversation, and had claimed that O’Bryan had called him a coward. O’Bryan denied that she had referred to Schwed as a coward. She also testified that she had never been reprimanded in the past for conversations not related to work, nor had her coworkers ever been disciplined for solicitations relating to football tickets or restaurants, for example.
On December 19, the union filed an unfair labor practices charge with the Board. On February 14, 1986, the parties entered into a settlement agreement in which the YMCA promised not to threaten employees with a cut in hours or any other type of retaliation because of their union involvement. The YMCA also agreed not to forbid union solicitation where the YMCA did not forbid other types of solicitation, and to rescind and remove the warning letter from O’Bryan’s personnel file. See rec., vol. II, r. ex. 10(a).
After the settlement agreement, the employees had further unionization meetings. Towards the end of February, just before Ague left on a vacation, a number of employees signed union authorization cards in Ague’s presence. One of these employees was Wes Beal. When Ague returned from her vacation, she discovered that Beal had been fired on March 5 for sexual harassment of Marnie Duke, a sixteen year-old high school student who worked at the Garden Ranch Center as a lifeguard and an instructor. Ague tried to get more information about the firing from other employees, but was unable to learn very much; her co-workers told her that she should talk to Duke if she wanted to learn more.
Ague testified she initially called Beal, who told her that he was “in a state of shock,” that “[h]e was extremely surprised at being fired,” and that he did not feel he had done anything to warrant the sexual harassment charge. Rec., vol. I, at 117. Ague asked him whether he thought his firing could be the result of union activities, and Beal responded that he may have aroused the hostility of YMCA management by defending Ague at one of the November meetings with Klever. According to Ague, she then “asked [Beal] if he [1447]*1447felt that he wanted to pursue this matter [with the union], and he said yeah, he thought he did.” Id. at 119.
Ague contacted the union representative, and agreed to give an affidavit on March 19 to an investigating Board agent. Shortly before she was scheduled to give the affidavit, Ague testified that she tried to discuss Beal’s firing with Sanford, but Sanford told her she was too busy to talk to her. Ague stated that Sanford promised to get back to her later, but did not.
After unsuccessfully attempting to speak to Duke at the YMCA on March 18, Ague told Duke she would call her at home, and she did so on the morning of March 19. According to Ague, she began the conversation by emphasizing that she was opposed to sexual harassment, and then she asked “ ‘what in the devil did [Beal] do to you to cause you ... to file a [sexual harassment grievance].’ ” Id. at 124.2 When Duke said she did not know, Ague was more specific and inquired whether Beal had touched her or asked her to go to bed with him. To each of these questions, Duke responded in the negative. Ague testified she then explained to Duke that she was calling because she had to give an affidavit that day and that she wanted to ascertain whether Beal had been fired for “the right reasons,” or because of his union activities. Duke did not elaborate on the substance of the sexual harassment charge, but suggested that Ague call another employee who had problems with Beal. Immediately after the conversation, Duke told her mother that Ague had just telephoned, and her mother called Weber after Duke left for school to express her anger that Ague had called and upset her daughter. Later that day, Weber spoke to Duke, and she relayed the conversation to him, including the fact that Ague was about to give an affidavit.
The next morning Weber, with Sanford, called Ague into his office to question her about the previous day's telephone conversation with Duke. Ague verified that she had asked Duke certain questions, and' she explained that she had been concerned that Beal was fired not for sexual harassment, but for his union activity. Ague also asked whether she could meet with Duke and Weber to discuss the charges. Weber told her that he would consider the matter and determine what action to take. Later that afternoon, Weber called Ague back into his office, where he told her she was being terminated for “gross interference in a sexual harassment complaint.” Id. at 134.
The union filed an unfair labor practices charge with the Board in which it alleged that the YMCA had discriminated against Ague by firing her because of her union activity, had coerced and restrained Ague because of her union activity, and had unlawfully discriminated against O’Bryan by issuing her a letter of reprimand. The administrative law judge ruled that the YMCA had violated sections 8(a)(1), (3), and (4) of the Act. In so doing, the AU set aside the settlement agreement because it found that the YMCA engaged in post-settlement unfair labor practices. The Board affirmed the findings and conclusions of the AU and adopted the AU’s order.
II.
The YMCA first argues that the YMCA’s impact on interstate commerce was insufficient to warrant the Board’s exercise of its jurisdiction. Board jurisdiction is of two types, statutory and discretionary. Statutory jurisdiction derives from section 10(a) of the Act, which grants the Board the power “to prevent any person from engaging in any unfair labor practice ... affecting commerce.” 29 U.S.C. § 160(a) (1988). Because Congress has vested in the Board “the fullest jurisdictional breadth constitutionally permissible under the Commerce Clause,” NLRB v. Reliance Fuel Oil Corp., 371 U.S. 224, 226, 83 S.Ct. 312, 313, 9 L.Ed.2d 279 (1963) (per curiam), the Board may exercise its broad statutory jurisdiction whenever “an em[1448]*1448ployer ‘has more than a de minimis impact on the flow of interstate commerce.’ ” NLRB v. Southeast Ass’n for Retarded Citizens, Inc., 666 F.2d 428, 430 (9th Cir.1982) (citation omitted).
Although its statutory jurisdiction is quite broad and therefore is not challenged by the YMCA, the Board has limited its jurisdictional reach under its discretionary powers. The Board curtails its jurisdiction by adhering to self-imposed minimum jurisdictional guidelines based on dollar amounts, which enables the Board to distinguish between those enterprises essentially local in character and those with a pronounced impact on the flow of interstate commerce. See R. Gorman, Labor Law § 2 (1976). A business generally must meet one of two relevant dollar limitations before the Board will assert its jurisdiction. If a business is a retail enterprise, it ordinarily must have a gross annual business volume of $500,000 and must make substantial purchases from or sales to other states on a direct or indirect basis. The Board will generally assert jurisdiction over a non-retail establishment if the gross outflow or inflow of revenues across state lines is at least $50,000. See NLRB v. Marsden, 701 F.2d 238, 241 (2d Cir.1983). Of course, it is important to remember that “all of the above dollar standards are adopted and applied as a matter of the Board’s discretion.... Thus, the Board has asserted jurisdiction regardless of whether its dollar standards have been satisfied where ‘public policy requires the Board to exercise jurisdiction to the fullest extent.’ ” Gorman, Labor Law § 2, at 25 (citation omitted). Furthermore, “[i]n light of the broad discretion given to the Board in the exercise of its jurisdiction, courts should intervene only where there is obvious unjust discrimination.” Southeast Ass’n, 666 F.2d at 431.
The YMCA raises several points in support of the argument that the Board inappropriately exercised its discretionary jurisdiction. First, the YMCA asserts that the AU incorrectly applied the retail standard to it. The basis for the YMCA’s argument is not altogether clear. It emphasizes its charitable character, and thus seems to equate retail with for-profit and non-retail with not-for-profit. As the AU correctly pointed out, however, it is the fact that the YMCA’s “services are directly to ultimate consumers,” rec., vol. Ill, doc. 1, at 5, that makes it a retail establishment. See, e.g., Bussey-Williams Tire Co., 122 NLRB No. 137, 43 LRRM 1266 (1959). The YMCA’s gross annual business volume and its purchases from other states satisfies this retail standard. Even if the YMCA is categorized as a non-retail establishment, the direct inflow of materials from outside of Colorado in 1986 was $56,700. This amount meets the Board’s jurisdictional guidelines.
The YMCA also argues that the Board should have asserted jurisdiction only upon finding that the YMCA had a “significant” impact on interstate commerce. Citing Ming Quong Children’s Center, 210 NLRB No. 125, 86 LRRM 1254 (1974), it contends that charitable organizations as a general rule do not have such an impact. This contention misstates the law. In The Rhode Island Catholic Orphan Asylum (St. Aloysius Home), 224 NLRB No. 70, 92 LRRM 1355, 1357 (1976), the Board expressly did away with the Ming Quong rule:
“[W]e see no reason to establish separate standards for institutions that seek to accomplish the same end but differ only in whether they are charitable or non-charitable. The sole basis for declining or asserting jurisdiction over charitable organizations will now be identical with those which are not charitable.”
That non-profit institutions should be analyzed for jurisdiction in a manner identical to that applied to their for-profit counterparts has been consistently reaffirmed. See NLRB v. Lighthouse for the Blind, 696 F.2d 399, 404 n. 21 (5th Cir.1983) (“ ‘Congress appears to have agreed that nonprofit institutions “affect commerce” under modern economic conditions’ ”) (quoting NLRB v. Yeshiva Univ., 444 U.S. 672, 681 n. 11, 100 S.Ct. 856, 862 n. 11, 63 L.Ed.2d 115 (1980)); Long Stretch Youth Home, Inc., 280 NLRB No. 79, 122 LRRM [1449]*14491272, 1275 (1986); Conway R.R. YMCA, 237 NLRB No. 178, 99 LRRM 1157, 1158 (1978) (“the Board for jurisdictional purposes no longer distinguishes between profit and nonprofit organizations”). Furthermore, it is irrelevant for jurisdictional purposes that an enterprise is wholly charitable in its purpose, as well as in its organizational structure.3 See The United Way of Howard County, Inc., 287 NLRB No. 98, 127 LRRM 1185 (1988) (nonprofit corporations engaged in activities solely for benevolent purposes cannot avoid the rule of St. Aloysius Home and the inclusion of such corporations within NLRB jurisdiction); Conway R.R. YMCA, 99 LRRM at 1158 (charitable or worthy purpose not basis for declining jurisdiction).
As with all organizations, charitable organizations must have a sufficient impact on interstate commerce for the Board to exercise its jurisdiction. See United Way, 127 LRRM at 1185. Because the YMCA has met the discretionary jurisdictional standards, see Greater Boston YMCA, 243 NLRB No. 70, 101 LRRM 1521 (1979), we conclude that the Board did not abuse its discretion in finding the YMCA’s impact on interstate commerce to be “sufficient.” 4
III.
The YMCA challenges the Board’s finding of unfair labor practices based on both pre-settlement and post-settlement conduct. With regard to pre-settlement conduct, the YMCA contends that the settlement agreement entered into by the parties precludes what in effect is relitigation of that earlier conduct. Even if the Board properly set aside the settlement agreement, the YMCA argues that the evidence is insufficient to find it committed unfair labor practices by interrogating Ague and reprimanding O’Bryan. It likewise argues that the evidence of post-settlement conduct is insufficient to support a finding that the firing of Ague constituted an unfair labor practice.
A.
As a preliminary matter, we note that a court reviewing a Board order “should grant enforcement if the Board correctly interpreted and applied the law and if its findings are supported by substantial evidence in the record, considered in its entirety.” Presbyterian/St. Luke’s Medical Center v. NLRB, 723 F.2d 1468, 1471 (10th Cir.1983); see also Universal Camera Corp. v. NLRB, 340 U.S. 474, 488-91, 71 S.Ct. 456, 464-66, 95 L.Ed. 456 (1951); Le’Mon v. NLRB, 902 F.2d 810, 812-13 (10th Cir.1990); 29 U.S.C. § 160(e) (1988) (“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”). Substantial evidence is defined as “ ‘such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.’ ” Universal Camera, 340 U.S. at 477, 71 S.Ct. at 459 (quoting Consolidated Edison Co. v. NLRB, 305 U.S. 197, 229, 59 S.Ct. 206, 217, 83 L.Ed. 126 (1938)).
B.
A settlement agreement is binding on all parties to it, but it “will be set aside if its provisions are breached or if postsettlement unfair labor practices are committed.” Lawyers Coop. Publishing Co., 273 NLRB No. 31, 118 LRRM 1213, 1215 n. 4 (1984); see also Soule Glass & Glazing Co. v. NLRB, 652 F.2d 1055, 1109 (1st Cir.1981). If the settlement agreement [1450]*1450is set aside, the employer’s pre-settlement conduct may be assessed for unfair labor practices. Moreover, in order to determine whether post-settlement conduct constitutes an unfair labor practice, “presettlement conduct may be considered as background evidence in determining the motive or object underlying a respondent’s postset-tlement conduct.” Lawyers Coop., 118 LRRM at 1215 n. 4; see also NLRB v. Shurtenda Steaks, Inc., 397 F.2d 939, 945 (10th Cir.1968) (employer unfair labor conduct antedating settlement admissible to determine purpose and intent of post-settlement conduct); Mason & Hanger-Silas Mason Co., 270 NLRB No. 71, 116 LRRM 1073, 1074-75 (1984) (employer conduct pri- or to settlement agreement relevant regarding lack of anti-union animus).
Because a finding of a post-settlement unfair labor practice or breach of a provision of the settlement agreement is necessary before the pre-settlement conduct can be re-examined, we turn first to the issue of Ague’s discharge, which is the basis of her claim that the YMCA committed post-settlement unfair labor practices.
C.
The AU found that the discharge of Ague constituted an unfair labor practice in violation of sections 8(a)(1), (3), and (4).5 A violation of sections 8(a)(1) and (3) occurs where four factors are present. An employee must have been engaged in concerted activity, the employer must have known of the concerted nature of the activity, the concerted activity must be protected under the Act, and the employer’s discrimination must have been motivated by the employee’s protected concerted activity. See Meyers Industr. (Meyers I), 268 NLRB 493, 115 LRRM 1025, 1029 (1984), remanded on other grounds, Prill v. NLRB, 755 F.2d 941 (D.C.Cir.1985), cert. denied, Meyers Industr., Inc. v. Prill, 474 U.S. 948, 106 S.Ct. 313, 88 L.Ed.2d 294 (1985), on remand, 281 NLRB No. 118, 123 LRRM 1137 (1986), aff'd, Prill v. NLRB, 835 F.2d 1481 (D.C.Cir.1987), cert. denied, 487 U.S. 1205, 108 S.Ct. 2847, 101 L.Ed.2d 884 (1988).
Section 7 of the Act, 29 U.S.C. § 157 (1988), guarantees that employees “have the right to self-organization, 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.” The AU, focusing on Ague’s telephone call to Duke, found that call to be “concerted activity” within the meaning of section 7.6
The YMCA disputes the finding of concertedness. It asserts, for example, [1451]*1451that no employee specifically asked Ague to telephone Duke, that Beal admitted his discharge was due to his sexual harassment of Duke, that Beal never stated he was certain his discharge was due to his union activities, and that it was Ague who suggested taking a complaint to the union. These contentions by the YMCA are either inaccurate or irrelevant. Our review of the record shows that while Beal emphasized he was charged with sexual harassment, he did not understand why he had been fired, and that perhaps it was a result of his support of Ague at the meeting with Klever. The fact that Ague suggested further investigation and consultation with the union is completely irrelevant. Concerted activity is activity “engaged in with or on the authority of other employees, and not solely by and on behalf of the employee [herself].” Meyers I, 115 LRRM at 1029. Evidence that Ague received authority from Beal to pursue the matter on his behalf is sufficient to support a finding of “concert-edness.” 7 See B & P Motor Express Inc. v. NLRB, 413 F.2d 1021, 1023 (7th Cir.1969) (action in support of fellow employee over her grievance is concerted activity within meaning of section 7); see also rec., vol. Ill, doc. 4, at 2 (Board found that “Ague’s telephone call to Duke was concerted activity engaged in with or on the authority of other employees, and not solely by and on behalf of the employee herself”).
The YMCA then contends that the AU had insufficient evidence to support her finding that the YMCA knew Ague’s telephone call to Duke was concerted activity protected under section 7.8 We disagree. As the AU noted, Duke told Weber that Ague had referred to an “affidavit” she had to give. See id., doc. 1, at 25. Additionally, Ague testified that she expressed her concern about Beal’s discharge to Sanford prior to her telephone call to Duke. See rec., vol. I, at 121.
The YMCA’s next contention is that Ague’s telephone call caused harm as defined by Title VII of the Civil Rights Act, 42 U.S.C. § 2000e et seq. (1982), and created an intimidating and coercive environment for other employees in the exercise of their statutory rights. The call, according to the YMCA, therefore should lose the protection of the Act. In support of its argument, the YMCA engages in a lengthy discussion in which it emphasizes the potential liability it would face for any acts of retaliation against a sexually-harassed employee and for acts of sexual harassment of one of its employees by another. We agree with the AU that these arguments lack merit. Title VII makes it unlawful “for an employer to discriminate against any” employee who has complained of sexual harassment. 42 U.S.C. § 2000e-3(a) (1982) (emphasis added). Ague was neither the employer nor acting on her employer’s behalf. Unlike Arnold v. City of Seminole, 614 F.Supp. 853, 859, 870 (E.D.Okl.1985), which the YMCA cites, this case does not involve a city police chief threatening a plaintiff with discharge if she pursued her right to be free of sexual harassment. Here, by contrast, Ague was not in a position of authority over Duke, nor was she threatening her with discharge. This is also not a case in which the telephone call contributed to the hostile working environment envisioned by Title VII, since the regulations prohibit “verbal or physical conduct of a sexual nature ... [which] has the purpose or effect of ... creating an intimidating, hostile, or offensive working environment.” 29 C.F.R. § 1604.11(a) (1989) (emphasis added). Ague’s conduct is not consistent with that described by the regulations.
Finally, we must consider whether Ague’s concerted activity should lose the protection of the Act because it was otherwise “unlawful, violent, in breach of contract or ‘indefensible.’ ” Coors Container [1452]*1452Co. v. NLRB, 628 F.2d 1283, 1287 (10th Cir.1980), citing NLRB v. Washington Aluminum Co., 370 U.S. 9, 17, 82 S.Ct. 1099, 1104, 8 L.Ed.2d 298 (1962). We have reviewed the record, and we agree with the AU that Ague’s conduct does not fall into any of these unprotected categories, nor does it “amount to egregious misbehavior that should rob this effort to assist fellow employee Beal of its protected character,” rec., vol. Ill, doc. 4, at 3. Although Ague’s call was somewhat imprudent and “lacking in sensitivity,” id,., doc. 1, at 26, there is substantial evidence to conclude that Ague was simply attempting to ascertain whether Beal’s discharge was union-related.9
The fourth and final factor we must consider is whether Ague’s discharge was motivated by her protected activity. The YMCA does not dispute that Ague’s telephone call to Duke to investigate Beal’s discharge, determined to be a concerted, protected activity, was the basis for her discharge. This alone would be sufficient for a section 8(a)(1) and (3) violation. But even if the telephone call itself were not protected, we agree that the YMCA failed to prove by a preponderance of the evidence that Ague’s discharge rested on her unprotected conduct, and not on her union activity. See NLRB v. Transportation Management Corp., 462 U.S. 393, 399-403, 103 S.Ct. 2469, 2473-75, 76 L.Ed.2d 667 (1983);10 see also Head Division, AMF, Inc. v. NLRB, 593 F.2d 972, 975 (10th Cir.1979) (“the discharge of employees who are actively engaged in union affairs gives rise to an inference of impermissible, anti-union discrimination”). The YMCA failed to prove that the telephone call was anything but a pretext for Ague’s discharge. Furthermore, we agree with the AU that because the YMCA generally required employees engaged in comparable conduct to undergo counseling but did not discharge them, the
“disparity and severity of the discipline accorded Ague is indicia of unlawful motivation, and warrants an inference that [the YMCA] seized upon this telephone conversation in order to rid itself of the leading union adherent; and that she would not have been discharged but for her union activities.”
Rec., vol. Ill, doc. 1, at 27-28 (citation omitted). The Board’s determination that the YMCA violated sections 8(a)(1) and (3) by discharging Ague is therefore supported by substantial evidence.
The AU also found that the YMCA, by discharging Ague because she gave an affidavit to a Board agent, violated section 8(a)(4), which prohibits discrimination against an employee who gives testimony in an unfair labor practices investigation. The YMCA contends that this finding is not supported by substantial evidence because there was no proof it had knowledge of Ague’s intention to give an affidavit, and because Ague was terminated solely for interfering with a sexual harassment investigation. As the AU noted, however, Duke told Weber of Ague’s intention to give an affidavit, and the unfair labor prac[1453]*1453tice charge concerning Beal’s discharge was received by Weber’s office prior to Ague’s discharge. Since we have already held that the evidence supports a finding that Ague’s investigation, a concerted and protected activity, motivated her termination, we conclude there is substantial evidence that the YMCA violated section 8(a)(4).
D.
The YMCA argues that its post-settlement conduct was unrelated to the pre-settlement conduct, and that this conduct therefore should not be used to set aside the agreement. In support of its position, the YMCA cites to Deister Concentrator Co., 253 NLRB No. 40, 106 LRRM 1053, 1056 (1980), which held that rescission of a settlement agreement was unnecessary where the employer had substantially complied with the agreement and where post-settlement violations were essentially unrelated to the subject matter of the agreement. Here, by contrast, we have upheld the Board’s conclusion that the YMCA effectively violated the agreement by retaliating against Ague for her activities on behalf of the union. See rec., vol. II, g.c. ex. 1(h), at 2 (settlement agreement). Moreover, the YMCA’s pre- and post-settlement conduct were related since, as the ALJ observed, the prior conduct included threats of action against Ague, and the latter “involve[d] the implementation of those threats—her discharge.” Rec., vol. Ill, doc. 1, at 24. Accordingly, we reject the YMCA’s arguments and agree with the Board that the settlement agreement was properly set aside. We therefore turn to an assessment of the pre-settlement conduct.11
The YMCA objects to four findings of the AU concerning the pre-settlement conduct. It contends that the Weber/Ague conversation did not constitute coercive interrogation; that Kirkland’s comments to Ague were not coercive; that Klever’s statements to Ague during the meeting were not coercive; and that the letter of reprimand to O’Bryan because of her discussion with Schwed did not violate sections 8(a)(1) and (3). We have reviewed the record as a whole with due regard for the ALJ’s responsibility to judge the demeanor and credibility of the witnesses. We are persuaded there is substantial evidence to support the AU’s findings.
We therefore grant enforcement of the Board’s order.