Petition for review granted and cross-application for enforcement granted in part by published opinion. Judge WILLIAMS wrote the majority opinion, in which Judge LUTTIG joined. Judge MICHAEL wrote a dissenting opinion.
OPINION
WILLIAMS, Circuit Judge:
Sam’s Club, a division of Wal-Mart Stores, Inc., (Sam’s) petitions for review from the National Labor Relations Board’s (the Board) final order determining that it had committed violations of § 8(a)(1) and (a)(3) of the National Labor Relations Act (the Act). See 29 U.S.C.A. § 158(a)(1) & (a)(3) (West 1973 & Supp. 1998). The Board cross-petitions for enforcement of its order. For the reasons stated herein, we grant Sam’s petition for review, grant the Board’s cross-petition for enforcement in part and deny it in part.
I.
This case involves a series of unfair labor practice charges arising out of Local 400, United Food and Commercial Workers Union’s (the Union) attempt to organize the workers at Sam’s in Land over Crossing, Maryland. The campaign culminated in an election held on July 8, 1994, during which the Sam’s workers cast votes indicating whether they desired Union representation.1 The factual discussion that follows is drawn from the ALJ’s findings, the record, and the parties’ briefs.
In January 1994, Sam’s, a wholesale warehouse that sells goods at discount prices to fee-paying members, purchased a store that had been operating as a Pace Membership Warehouse (Pace). Sam’s took over the store, retained 95% of the employees, and swiftly began to implement policies and procedures mandated by its parent company, Wal-Mart. Prior to Sam’s purchase of Pace, the Union unsuccessfully had attempted to organize the workers at Pace. Several of the employees retained by Sam’s harbored strong pro-union sentiment. As a result, after Sam’s opened, the Union began organizing a new.2 During the course of the Union’s [237]*237attempt to organize Sam’s, three incidents relevant to this petition for review allegedly occurred.
A.
As employees and management at Sam’s were gearing up for the election, Union matters were a frequent topic of conversation. During one such conversation, in April 1994, a front-end employee, Danielle Porter, commented to the front-end supervisor, Debra Belt, while they were alone in an office that she hoped that the Union won the election. One of the women, either Porter or Belt, thereafter commented that Sam’s would likely close the Landover store if the Union won the election, and the other woman agreed with that statement. It is not clear from the record which of the two women actually made the statement that she thought Sam’s would close. The Union filed an unfair labor practice charge alleging that in this encounter Belt had threatened an employee by stating that the store would close if the Union won the election.
B.
On March 30, 1994, Lawrence Perez, a member of the Union’s organizing committee, asked his manager whether he could take his fifteen minute break. The manager told him to wait until another employee returned from break. Nevertheless, Perez immediately took his break. As a result, the manager issued a written warning for his insubordination. Subsequently, Perez refused to sign the warning form and claimed that he had done nothing wrong. Considering this refusal to sign the warning to be a further act of insubordination, the supervisor issued the next level of discipline, a “Day of Decision,” a one-day suspension with pay during which Perez was instructed to think about what he had done wrong and return with a written plan of action on how to correct the behavior in the future. The Union filed an unfair labor practice charge asserting that Perez was unlawfully and dis-criminatorily suspended for supporting the Union.
C.
During the course of the Union’s election-related activities at Sam’s, two special union representatives (SPURS), Tracie Burris and Terry Adgerson, were assigned to work at Sam’s from late May 1994 through the election in July. Their purpose was to canvass the workers and speak to them about the benefits of unionization. Frequently, Burris and Adgerson would discuss Union matters in front of Sam’s in the parking lot during shift change when the employees would be entering and exiting the store. Often, the operations manager, Stan Harris, would encounter the SPURS on. his routine front-end safety checks. Harris would exchange friendly greetings with Burris and Adgerson while they were discussing the Union with employees, and according to the testimony of Burris and Adgerson, occasionally would comment that Wal-Mart was a powerful company that would not tolerate a union. No unfair labor practice charge was filed as a result of these encounters between the SPURS and Harris, however, the General Counsel litigated this charge before the ALJ.
II.
As a result of the foregoing events, as well as others not relevant to this petition, the Union filed three charges, each listing numerous objections to election activity3 and unfair labor practices.4 As a result, [238]*238complaints issued, consolidated and heard before an ALJ for several days in the spring of 1995.
During the course of the hearing, the General Counsel discovered two witnesses of whom it previously had been unaware, the SPURS. Burris and Adgerson appeared at the hearing and presented testimony that Sam’s operations manager, Harris, had on several occasions made threats that Wal-Mart would close the store if the Union were voted in. According to Burris and Adgerson, Harris’s threats were made in direct response to conversations with several of Sam’s front-end employees about the benefits of Union membership. The General Counsel, after presenting the SPURS’ testimony, moved for an amendment to the complaint to incorporate unfair labor practice charges stemming from Harris’s unlawful threats of store closing. The ALJ allowed the amendment over Sam’s objection and allowed Sam’s additional time to defend against the new allegation.
After the hearing, the ALJ issued an opinion in which it determined that Sam’s had violated § 8(a)(1) and (a)(3) of the Act5 when: (1) Belt had threatened Porter that if the Union were victorious in the election the store would close; (2) a manager had discriminatorily disciplined Perez; and (3) Harris had threatened several employees that if the Union were successful in its election bid, Sam’s would shut down.6 As a result of these findings, the ALJ ordered Sam’s to cease and desist from its illegal acts, remove from its personnel files any reference to Perez’s unlawful discipline, and post a notice in the Landover Sam’s. Sam’s appealed the ALJ’s decision to the Board. With only minor modifications, the Board affirmed the ALJ’s opinion in all respects and adopted the ALJ’s proposed order. Thereafter, Sam’s filed the instant [239]*239petition for review. The Board cross-petitions for enforcement of its order.7
Sam’s petitions for review on several grounds. First, Sam’s argues that the unfair labor practice findings relating to the actions of Belt and Perez are not supported by substantial evidence and should be overturned. Next, Sam’s contends that the amendment of the complaint to incorporate a charge that Harris threatened employees violated § 10(b) of the Act. 29 U.S.C.A. § 160(b) (West 1973). Also, Sam’s asserts that this amendment violated its right to fundamental fairness and due process. Further, Sam’s asserts that if the amendment of the complaint was proper, the unfair labor practice finding stemming from the actions of Harris was not supported by the evidence presented at the hearing.
We reverse the Board’s finding that Belt unlawfully threatened Porter because that conclusion is not supported by substantial evidence. Because the Board used faulty analysis in determining that Perez was the victim of anti-Union animus, and as a result the unfair labor practice finding is not supported by substantial evidence, we also reverse that unfair labor practice finding. Finally, because we agree with Sam’s that the amendment of the complaint to include the charge that Harris threatened employees was improper, we reverse that unfair labor practice determination as well.
III.
The Board’s legal interpretations of the NLRA are entitled to deference. See Holly Farms Corp. v. NLRB, 517 U.S. 392, 116 S.Ct. 1396, 1406, 134 L.Ed.2d 593 (1996). If the Board’s interpretations are “rational and consistent with the Act,” they will be upheld by reviewing courts. Fall River Dyeing & Finishing Corp. v. NLRB, 482 U.S. 27, 42, 107 S.Ct. 2225, 96 L.Ed.2d 22 (1987). When we review mixed questions, the Board’s application of legitimate legal interpretations to the facts of a particular case should be upheld if they are supported by substantial evidence based upon the record as a whole. See id.; Beth Israel Hospital v. NLRB, 437 U.S. 483, 501, 98 S.Ct. 2463, 57 L.Ed.2d 370 (1978). Likewise, the Board’s factual determinations are “conclusive” if they are “supported by substantial evidence on the record considered as a whole.” 29 U.S.C.A. § 160(e) (West 1973); see also Universal Camera Corp. v. NLRB, 340 U.S. 474, 493, 71 S.Ct. 456, 95 L.Ed. 456 (1951). Substantial evidence is “more than a scintilla” but “less than a preponderance” of evidence. Richardson v. Perales, 402 U.S. 389, 401, 91 S.Ct. 1420, 28 L.Ed.2d 842 (1971). Substantial evidence is “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion.” Consolidated Edison Co. v. NLRB, 305 U.S. 197, 229, 59 S.Ct. 206, 83 L.Ed. 126 (1938); see also Allentown Mack Sales & Serv., Inc. v. NLRB, 522 U.S. 359, 118 S.Ct. 818, 823, 139 L.Ed.2d 797 (1998) (describing substantial evidence as enough evidence so that “on [the] record it would have been possible for a reasonable jury to reach the Board’s conclusion”). “Substantial evidence review is an objective assessment of the sufficiency of the evidence.” Pirelli Cable Corp. v. NLRB, 141 F.3d 503, 514 (4th Cir.1998) (citing Allentown Mack, 118 S.Ct. at 828).
During the process of reviewing the entire record for substantial evidence, a reviewing court must not only consider the evidence used to support the Board’s factual conclusion, but it also “must take into account whatever in the record fairly detracts” from the Board’s factfinding. Universal Camera, 340 U.S. at 487-88, 71 S.Ct. 456. “When the Board purports to be engaged in simple factfinding, ... it is not free to prescribe what inferences from the evidence it will accept and reject, but [240]*240must draw all those inferences that the evidence fairly demands.” Allentown Mack, 118 S.Ct. at 829. “Courts performing substantial evidence review, therefore, must examine whether the Board considered all of the reasonable inferences compelled by the evidence in reaching its decision.” Pirelli Cable Corp., 141 F.3d at 514.
An ALJ’s credibility determinations should be accepted by the reviewing court absent exceptional circumstances. See NLRB v. CWI of Maryland, Inc., 127 F.3d 319, 326 (4th Cir.1997). Exceptional circumstances include those instances when “a credibility determination is unreasonable, contradicts other findings of fact, or is based on an inadequate reason or no reason at all.” Id. (internal quotation marks omitted). Additionally, credibility determinations that are supported only by “generalized, conclusory statements] purportedly incorporating a host of individual comparative credibility determinations with respect to multiple witnesses” are not entitled to deference review. Be-Lo Stores v. NLRB, 126 F.3d 268, 279 (4th Cir.1997).
We review the Board’s decision accordingly.
IV.
Sam’s first challenges the Board’s determination that it violated § 8(a)(1) of the Act when supervisor Debra Belt threatened employee Danielle Porter that the Landover Sam’s would be closed if the Union were successful (Porter-Belt incident). Sam’s claims that this unfair labor practice finding is not supported by substantial evidence because its sole evidentiary support is an ex parte affidavit that was never entered into evidence during the hearing.
The Porter-Belt incident occurred on April 14, 1994, and was included in the Union’s charges filed with the Regional Director on April 24, 1994. Shortly thereafter, on May 5, 1994, Porter made as worn statement before representatives of the Board. In her statement, Porter reported: “I was talking to Deborah Belt ... about getting a union. I told her that I hoped we would get a union or at least vote on it. She told me that’s not what I wanted because Sam’s would probably close the store because they didn’t tolerate unions.”8 (J.A. at 179, testimony of Danielle Porter.)
During the hearing, which occurred approximately one year after the Porter-Belt incident transpired, Porter asserted that she herself raised the specter of Sam’s closing in response to a successful Union organizing campaign. Porter said that during her conversation with Belt, she first stated that the Sam’s might close if the Union won the election and that Belt simply agreed with her by saying that Porter was probably right. In response to Porter’s testimony that Belt had not directly threatened her, but rather simply agreed with Porter’s fears about the consequences of Union organization at Sam’s, the General Counsel proceeded to impeach Porter with her prior sworn statement. The General Counsel invited Porter to explain why the 1994 affidavit differed from her hearing testimony. Porter revealed that the statement was the product of a question and answer process during which she was instructed “to just simply answer the questions” posed by a Board representative. (J.A. at 179.) Porter stated that she was asked only if any manager had spoken with her about the consequences of a Union victory in the election, and that she responded that she and Belt had had such a conversation. Porter further explained that during the time her statement was taken she was never asked about the sequence of the conversation or who said what to whom. In sum, during the hear[241]*241ing Porter asserted that the affidavit accurately reflected the general contents of the conversation that occurred during the Porter-Belt incident, but that it did not accurately reflect the details of the interchange.
In her decision, the ALJ made a credibility determination and concluded that Porter’s ex parte statement was more believable than her live testimony because at the time of the hearing she was still a Sam’s employee and “was extremely reluctant to testify against her employer’s interests.” (J.A. at 125.) In light of that credibility determination, the ALJ found that Sam’s had violated § 8(a)(1) of the act.
Sam’s asserts that the ALJ erred in concluding that it had violated § 8(a)(1) based solely upon four lines from Porter’s ex parte statement. Because the General Counsel never entered the affidavit into evidence during the hearing, Sam’s argues that there was no evidence to support the ALJ’s determination that it violated § 8(a)(1) and that therefore, the unfair labor practice finding was not supported by substantial evidence on the record as a whole.
We agree with Sam’s that the § 8(a)(1) violation resulting from the Porter-Belt incident was not supported by substantial evidence and must be reversed. NLRB unfair labor practice hearings “shall, so far as practicable, be conducted in accordance with the rules of evidence applicable in the district courts of the United States under the rules of civil procedure applicable for the district courts of the United States.” 29 U.S.C.A. § 160(b) (1973). Applying the rules of evidence, Porter’s affidavit, because it was never entered into evidence during the hearing, was properly used by the General Counsel as impeachment evidence only. Therefore, the ALJ was entitled to base only its credibility determination upon it. The statement was not entitled to substantive weight. See Community Counselling Serv., Inc. v. Reilly, 317 F.2d 239, 243 (4th Cir.1963) (“[T]he general rule is that ... [tjhe pretrial statement is usable on cross-examination, for purposes of impeachment, to present earlier, contradictory statements, but it is not substantive evidence of the truth of the extra-judicial statements.”). Thus, the ALJ erred when she used evidence included in the hearing only for impeachment purposes as substantive evidence that an unfair labor practice had occurred. Cf. Michigan v. Harvey, 494 U.S. 344, 353-54, 110 S.Ct. 1176, 108 L.Ed.2d 293 (1990) (noting the distinction between substantive evidence and impeachment evidence); United States v. Leon, 468 U.S. 897, 910, 104 S.Ct. 3405, 82 L.Ed.2d 677 (1984) (same). Because no other evidence supported the unfair labor practice determination, it must be reversed.
The law of evidence supplies ample explanation for this rule. Out-of-court statements used to support the truth of the matter asserted therein are, by definition, hearsay. See United States v. Lewis, 10 F.3d 1086, 1091 (4th Cir.1993). Technically, a presumption of unreliability applies to hearsay evidence. See, e.g., United States v. Love, 134 F.3d 595, 607 (4th Cir.1998) (discussing reliable hearsay); United States v. Clark, 18 F.3d 1337, 1342 (6th Cir.1994) (stating that out-of-court statements are presumptively unreliable). That presumption must be rebutted by a showing of reliability before the hearsay evidence can stand in support of a substantive proposition. See Fed. R.Evid. 801(d)(1) (providing that a prior inconsistent statement is not hearsay and therefore admissible if the witness is subject to cross-examination concerning the statement and the statement was made under oath subject to penalty of perjury at a trial, hearing, or other proceeding, or in a deposition). The General Counsel never made a motion to enter Porter’s affidavit into evidence. As a result, Sam’s never had an opportunity to contest the document’s reliability and the ALJ never had a meaningful chance to examine that issue. Thus, the affidavit was never properly ad[242]*242mitted as substantive evidence during the hearing and the ALJ’s use of it as such was error. See Fed. R. of Evid. 105 (discussing the admission of evidence for limited purposes). Cf. United States v. Ince, 21 F.3d 576, 580 (4th Cir.1994) (discussing distinction between substantive and impeachment evidence); Martin v. United States, 528 F.2d 1157, 1160-61 (4th Cir.1975) (reversing conviction when impeachment evidence was erroneously used substantively).
Because the ex parte statement could not be used as substantive evidence, and the ALJ determined Porter’s live statements were not credible, an evidentiary vacuum was created surrounding the Porter-Belt incident. There was simply no substantive evidence that Belt ever made a threatening statement to Porter. An unfair labor practice finding cannot be sustained when there is no substantive evidence supporting it,9 and therefore we reverse the Board’s determination that the Porter-Belt incident was a violation of § 8(a)(1) of the Act.10
V.
Sam’s next challenges the ALJ’s conclusion, affirmed by the Board, that Perez was the victim of anti-union discrimination in violation of § 8(a)(1) & (a)(3) of the Act. Sam’s argues that the ALJ’s conclusion that Perez was unfairly disciplined twice for the same infraction was incorrect because the ALJ did not consider adequately the non-discriminatory reason for the second discipline that Sam’s articulated at the hearing. We agree, and accordingly reverse.
The Board applies a shifting burden of proof to determine whether a discriminatory animus led an employer to discipline an employee in violation of § 8(a)(3) of the Act. See NLRB v. CWI of Md., Inc., 127 F.3d 319, 330-31 (4th Cir.1997). First, the General Counsel must prove by a preponderance of the evidence that the employer was motivated, at least in part, by anti-union discriminatory intent when it made its decision to alter the employee’s terms of employment. See id. The General Counsel must demonstrate three elements to meet this requirement: (1) that the employee had been engaged in protected activity, (2) that the employer knew of the activity, and (3) that such activity was a substantial or motivating reason for the employer’s action. See id. at 330; ARA Leisure Servs., Inc. v. NLRB, 782 F.2d 456, 462 (4th Cir.1986); NLRB v. Daniel Construction Co., 731 F.2d 191, 197 (4th Cir.1984). Either direct or circumstantial evidence maybe used. See NLRB v. Low Kit Mining Co., 3 F.3d 720, 728 (4th Cir.1993).
If the General Counsel can meet that burden by a preponderance of the evidence, the employer may nevertheless overcome the unfair labor practice charge if it can show that the terms of employment would have been affected even in the absence of union activity. See NLRB v. Transportation Management Corp., 462 U.S. 393, 401, 103 S.Ct. 2469, 76 L.Ed.2d 667(1983). “Thus, an employer might [243]*243show that a worker’s deficiencies, economic necessity, or a legitimate business policy compelled” disciplinary or other adverse action. See ARA Leisure Servs., Inc., 782 F.2d at 462.
“When confronted with evidence of a legitimate business motive, General Counsel must prove by a preponderance of the evidence that union antipathy did actually play a part in the decision.” NLRB v. Instrument Corp., 714 F.2d 324, 327 (4th Cir.1983). In deciding what motivated the employer, the Board may not simply declare that the stated reasons for the disciplinary action are pretextual. Rather, the General Counsel must put forth substantial evidence that anti-union animus motivated the employer’s choice. See id. at 327-28.
Perez was a member of the Union’s organizing committee and from the record it is clear that Sam’s had knowledge of that fact. The Board cites virtually no evidence, however, to support the conclusion that Perez’s Union activity was a substantial or motivating reason for Sam’s decision to issue Perez a “Day of Decision.” The ALJ noted only the “arbitrary and vindictive” nature of the disciplinary action taken against Perez.
Even assuming that the evidence is sufficient to prove by a preponderance the General Counsel’s initial burden that the suspension was motivated in part by anti-union discriminatory animus, which we doubt, we conclude that Sam’s clearly met its burden of showing that it suspended Perez for one day with pay for a legitimate, non-pretextual reason.
The ALJ’s conclusion that Perez was' disciplined twice for the same infraction is contradicted by unrebutted testimony on the record. Perez was disciplined twice, once for each of two acts of insubordination. First Perez was insubordinate when he took his fifteen minute break despite being told by his supervisor to wait until another employee returned. Perez also was insubordinate when he refused to sign the counseling sheet or admit that his prior behavior regarding the break was improper. Perez testified that he defied his manager’s instruction to wait before taking his break and the ALJ credited that testimony. It is also unrebutted that Perez refused to sign the coaching form or admit that he had exercised poor judgment: Clearly, Perez’s refusal to follow the reasonable instructions of his manager to post-pone his break and to follow Sam’s counseling protocol was inappropriate behavior that had nothing to do with his Union activity. Likewise, the managers’ actions in disciplining Perez twice for the separate acts of insubordination were a legitimate response. Nothing in the record indicates that the same disciplinary actions would not have been meted out in the absence of Perez’s Union affiliation. Union activity should not serve to insulate an insubordinate worker from a company’s routine disciplinary process. See Procter & Gamble Manufacturing Co. v. NLRB, 658 F.2d 968, 980 (4th Cir.1981) (“[U]nion activities do not immunize [an employee] from discipline.”). Therefore, even assuming that the general counsel met its burden of establishing that Sam’s was motivated in part by anti-union animus, Sam’s met its affirmative burden of showing that Perez was disciplined for a legitimate reason and would have been disciplined regardless of any improper motive.
Here, the Board’s apparent conclusion that Sam’s explanation was pretextual11 is not supported by substantial evidence. [244]*244See Medeco Security Locks, Inc. v. NLRB, 142 F.3d 733, 742 (4th Cir.1998) (noting that the Board’s conclusion that an employer’s affirmative defense is pretextual must be supported by substantial evidence on the record as a whole). The ALJ’s conclusion rests upon the smallest strand of evidence — that when a different supervisor issued two coaching forms to another employee for the same set of unexcused absences, the supervisor withdrew the second coaching form upon consultation with the general manager.
This evidence simply is not sufficient to support the ALJ’s conclusion. The ALJ compared an occasion of concededly dupli-cative disciplinary action with an instance in which an employee received two disciplinary sanctions for two different infractions. The fact that the Sam’s supervisors were willing to correct errors in their disciplinary process is not at all probative on the point of whether Perez legitimately would have been disciplined absent his union activities or was merely disciplined twice for the same infraction because of his union activity. The ALJ’s conclusion that Kramer acted arbitrarily and vindictively while disciplining Perez is especially dubious in light of the fact that the comparator whose disciplinary record was corrected also was involved heavily in the Union organizing campaign.
Further, the ALJ disregarded a compelling inference to be drawn from this evidence. When faced with a situation in which a supervisor incorrectly had issued double discipline for the same infraction, Kramer acted to correct the disciplinary records without regard to the employee’s Union activity. “When the Board purports to be engaged in simple factfinding, ... it is not free to prescribe what inferences from the evidence it will accept and reject, but must draw all those inferences that the evidence fairly demands.” Allentown Mack, 118 S.Ct. at 829.
We cannot conclude that the evidence relied upon by the ALJ is substantial evidence to support the conclusion that the affirmative defense was pretextual. The observation regarding Kramer’s willingness to withdraw erroneous duplicative discipline for one Union activist but not to withdraw the second of two distinct disciplinary actions for another Union activist is insufficient to constitute “such relevant evidence as a reasonable mind might accept as adequate to support a conclusion,” Consolidated Edison Co. v. NLRB, 305 U.S. 197, 229, 59 S.Ct. 206, 83 L.Ed. 126 (1938), that management treated Perez unfairly in light of their affirmative defense that Perez was disciplined twice for two separate infractions. Therefore, we reverse.
VI.
Finally, Sam’s challenges the Board’s affirmance of the ALJ’s decision to permit the General Counsel to amend the complaint during the hearing to include a charge that, while employees were conversing with the SPURS outside Sam’s front entrance, the operations manager, Harris, had unlawfully threatened several employees that Sam’s would close the store if the Union won the election (Harris allegation). The General Counsel’s initial consolidated complaint made no reference to Harris; rather the Porter-Belt incident was the only instance of anti-Union threats referenced in the complaint. Sam’s asserts that amending the complaint to include the Harris allegation violated § 10(b) of the Act.
Section 10(b), 29 U.S.C.A. § 160(b) (West 1973), operates as a statute of limitations on the filing of unfair labor practice charges. Under § 10(b), the charges incorporated in the complaint must be based upon events occurring within six months prior to the filing of a charge with the Board. See id. (“[N]o complaint shall issue based upon any unfair labor practice occurring more than six months prior to the filing of the charge with the Board.”). The purpose of § 10(b) is to assure a party that on any given day its liability under the Act is limited to incidents that oc[245]*245curred within the preceding six months. See Local Lodge No. 1424 v. NLRB, 362 U.S. 411, 419, 80 S.Ct. 822, 4 L.Ed.2d 832 (1960).
Nevertheless, a complaint may be amended at any time prior to the issuance of a final order adjudicating the charges alleged in the complaint. See 29 U.S.C.A. § 160(b) (“Any such complaint may be amended ... at any time prior to the issuance of an order based thereon.”). When an amendment is offered alleging new illegal activity not contained in the initial charges giving rise to the complaint, the acts alleged in the amendment must be “closely related” to the charges timely filed with the Board. See FPC Holdings, Inc. v. NLRB, 64 F.3d 935, 941 (4th Cir.1995); accord Don Lee Distrib., Inc. v. NLRB, 145 F.3d 834, 844-45 (6th Cir.1998); Parsippany Hotel Management Co. v. NLRB, 99 F.3d 413, 417 (D.C.Cir.1996).
Sam’s first asserts that we should not reach the question of whether the Harris allegation and the Porter-Belt incident are “closely related.” Sam’s argues that the jurisprudence of § 10(b) requires that the facts underlying the proffered amendment occur before the action that comprises the factual underpinning of the timely filed charge. In this case, Sam’s correctly notes that the Harris allegation arose from acts that occurred after the Porter-Belt incident. Therefore, Sam’s contends that the Board exceeded its authority when it amended the complaint to include post-charge unlawful conduct.
Sam’s argument is misplaced. In NLRB v. Fant Milling Co., 360 U.S. 301, 79 S.Ct. 1179, 3 L.Ed.2d 1243 (1959), the Supreme Court examined the extent to which the Board may recognize events occurring after the filing of a charge upon which a complaint is based. Noting that the statute of limitations contained in § 10(b) does not apply “to conduct subsequent to the filing of the charge,” id. at 309 n. 9, 79 S.Ct. 1179, the Court held that the Board could address unfair labor practices “ ‘which are related to those alleged in the charge and which grow out of them while the proceeding is pending before the Board,’ ” id. at 309, 79 S.Ct. 1179 (quoting National Licorice Co. v. NLRB, 309 U.S. 350, 369, 60 S.Ct. 569, 84 L.Ed. 799 (1940)). The Board is not, however, given “carte blanche to expand the charge as they might please, or to ignore it altogether.” Id. (internal quotation marks omitted). Thus, for our purposes, the distinction Sam’s is drawing between acts that occurred before the charge was filed and acts that occurred after the charge is filed is not meaningful.12 In either case, the newly alleged unfair labor practice must be closely related to an allegation already contained in a timely filed charge.
To determine whether a new factual allegation is closely related to the charges already raised, we have adopted the Board’s test formulated in Redd-I, Inc. v. Sheet Metal Workers Int’l Ass’n, 290 NLRB 1115, available in 1988 WL 214320 (1988), and apply a three-factor analysis that examines:
(1) whether the allegations involve the same legal theory as the allegations in the charge, (2) whether the allegations arise from the same factual situation or sequence of events as the allegations in the charge, and (3) whether a respondent would raise the same or similar defenses to both allegations.
FPC Holdings, Inc., 64 F.3d at 941. Here, factors one and three are not disputed. Both Sam’s and the Board agree that the Porter-Belt incident and the Harris allegation involve the same legal theory— threats prohibited under § 8(a)(1) of the Act — -and that Sam’s was required to raise similar defenses to the two allegations. [246]*246The question before us, therefore, is whether the two incidents “arise from the same factual situation or sequence of events.” Id.
Sam’s argues that the Porter-Belt incident and the Harris allegation are factually dissimilar in several significant ways: (1) the Porter-Belt incident took place behind closed doors as a private conversation between two co-workers whereas the Harris allegation transpired in the parking lot at the entrance to Sam’s in front of several individuals; (2) Harris, Sam’s operations manager, was a much higher ranking official than was Belt; (3) Harris made the anti-Union statements in front of Union organizers; and (4) Harris allegedly made threats of store closure on several separate occasions whereas Belt made a single threat.
Two unfair labor practice allegations arise from the same factual situation or sequence of events when they demonstrate “ ‘similar conduct, usually during the same time period with a similar object.’” NLRB v. Overnite Transp. Co., 938 F.2d 815, 820 (7th Cir.1991) (quoting Redd-I, Inc., 290 NLRB No. 140, 1988 WL 214320 (1988)). A mere chronological relationship between the two events is not enough, see Drug Plastics & Glass Co. v. NLRB, 44 F.3d 1017, 1021 (D.C.Cir.1995), nor is it enough that the events simply occurred during the same union organizing campaign or reflected anti-union animus, see id. If, however, the two allegations are demonstrably part of an employer’s organized plan to resist union organization, they are closely related. See FPC Holdings, Inc., 64 F.3d at 941-42.
In FPC Holdings,13 we determined that two unfair labor practice accusations arose “from the same factual situation or sequence of events” when the actions were taken by the same managers against the same employees in response to the same catalyst. See id. at 942. In that case, two employees, DeCarlo and Zeback, filed charges with the Board stating that their employer had committed an unfair labor practice when it terminated them for their union activities. See id. at 940. After investigating the charges, it came to light that prior to termination, DeCarlo and Ze-beck had been threatened with termination after attending a union organizational meeting at a Big Boy Restaurant. See id. We held that the ALJ properly allowed amendment of the complaint to include a § 8(a)(1) charge incorporating the threats made prior to DeCarlo and Zebeck’s termination.
This facts of this case are not at all akin to the facts of FPC Holdings. 14 In FPC [247]*247Holdings, the new charge added in the complaint was the first step in the progression of events that resulted in the termination of two employees. The addition of the Harris charge is not similarly connected to those already contained in the complaint. Here, Harris and Belt are different managers with different levels of responsibility. Harris made his threats in public on several occasions to sizeable groups of several, largely unidentified, employees whereas Belt had only one single private conversation with Porter. Harris was not present during Porter’s conversation with Belt and there is no allegation that Porter and/or Belt were present during Harris’s statements. The Harris charge depicts a manager who would broadcast anti-union messages to all-comers in the parking lot of the store. Adding that charge to the complaint' on the basis of an intimate conversation regarding private concerns about the possible consequences of unionization is like mixing apples with oranges. Those charges are not closely related.
Additional factual differences between the Porter-Belt incident and the Harris allegation convince us that our conclusion that the two charges are not factually related is correct. The incidents did not occur during the same time period within the Union’s organizing campaign. The Porter-Belt incident occurred early in April, just as the Union campaign was beginning. The Harris allegation occurred late in the Union campaign, during the last six weeks leading up to the election when the SPURS were at Sam’s actively soliciting votes. Furthermore, there is no evidence on the record to support a conclusion that Sam’s was pursuing an effort or crusade against the Union through illegal means. In fact, the record reflects that Sam’s trained managers to prevent the occurrence of unfair labor practices.15 Harris testified that he was trained through the use of a pneumonic device— SPIT (signifying the words “spy, promise, interrogate, threaten”) — to avoid committing unfair labor practices diming the election campaign. Kent Kramer, the general manager, testified that during the period of election activity Sam’s stopped making "■discretionary promotions or pay increases to prevent the appearance of impropriety. Kramer also testified that Sam’s relied on formal. informational meetings to convey the company’s perspectives on unionization to the employees. The informational meetings were attended, and sometimes interrupted, by pro-Union employees who [248]*248were routinely given an opportunity to speak at the end of the meeting to share their views regarding the advantages of the Union.
As a result of the foregoing analysis, we conclude that the Porter-Belt incident and the Harris allegation were two discrete and insular occurrences over the course of the Union’s organizing campaign. They have no significant factual relationship to each other. Therefore, the amendment of the complaint to include the Harris allegation was improper and we reverse.16
VII.
Based upon the previous discussion, we grant Sam’s petition for review. We also grant the Board’s cross-petition for enforcement in part and deny it in part.
IT IS SO ORDERED