41

5. SHOWING OF INTEREST 

324-0125 et seq. 

324-2000 

324-4020-1400 

An employee or group of employees, or any individual or labor organization acting in the 

employees’ behalf, may file a representation petition under Section 9(c)(1)(A) of the Act. The 

Board is required to investigate any such petition which alleges that a “substantial number’’ of 

the employees desire an election, whether it is for certification or decertification. The Board has 

adopted the administrative rule that 30 percent constitutes a “substantial number.’’ Statements of 

Procedure, Section 101.18(a). This 30-percent rule applies to all representation petitions filed by 

or in behalf of a group of employees. 

The purpose of this requirement is to enable the Board to determine whether or not the filing 

of a petition warrants the holding of an election without the needless expenditure of Government 

time, efforts, and funds. River City Elevator Co., 339 NLRB 616 (2003); Pike Co., 314 NLRB 

691 (1994); S. H. Kress Co., 137 NLRB 1244, 1248 (1962); and O. D. Jennings & Co., 68 

NLRB 516 (1946). The showing-of-interest requirement is based on public policy and therefore 

may not be waived by the parties. Martin-Marietta Corp., 139 NLRB 925 fn. 2 (1962). The 

administrative determination of a showing of interest has no bearing on the issue of whether a 

representation question exists. Sheffield Corp., 108 NLRB 349, 350 (1954). 

The showing of interest is an administrative matter not subject to litigation. O. D. Jennings & 

Co., supra; River City Elevator Co., supra; General Dynamics Corp., 175 NLRB 1035 (1969); 

Allied Chemical Corp., 165 NLRB 235 (1967); and NLRB v. J. I. Case Co., 201 F.2d 597 (9th 

Cir. 1953). 

Specific issues which pertain to the showing of interest are treated below. 

5-100 Timeliness of Submission of a Showing of Interest 

324-4020-3000 

324-6033-6700 

324-6067-6700 

A showing must be submitted within 48 hours of the filing of the petition, but in no event 

later than the last day a petition might timely be filed. Statements of Procedure, Section 101.17; 

Mallinckrodt Chemical Works, 200 NLRB 1 (1972). CHM section 11024.1. See also Excel 

Corp. (Excell II), 313 NLRB 588 (1993), where the Board on reconsideration of its earlier 

decision at 311 NLRB 710 (1993) (Excel I), refused to permit additional showing to be filed after 

the window period. The Board in Excel II characterized its decision in Excel I as “an ill-advised 

departure’’ from precedent and the Board’s Rules. 

An exception to this rule, based on the special circumstances involved, was made in 

Rappahannock Sportswear Co., 163 NLRB 703 (1967). In that case, there was no bargaining 

history, and two rival unions were engaged in initial organization of the employer’s employees. 

The employer was aware of both organizational campaigns, and, on being notified that one of the 

unions had filed a petition, recognized, and executed a collective-bargaining agreement with the 

other. Although the showing of interest in support of that petition was not furnished to the 

Regional Office until the date the contract was executed, all cards predated the filing of the 

petition. The Board declined to apply Section 101.17, noting the manifest inequity in permitting 

the hasty signing of a contract to truncate the normal 48 hours for the filing of a showing of 

interest. See also Smith’s Food & Drug Centers, 320 NLRB 844 (1996), discussed under 

Recognition Bar (sec. 10-500). 
42 SHOWING OF INTEREST 

When the petitioner broadens its original unit to one that is substantially larger and different

from that originally petitioned for, the broadened unit request is treated like a new petition and

must be supported by an adequate showing of interest. Centennial Development Co., 218 NLRB 

1284 (1975). Cf. Brown Transport Corp., 296 NLRB 1213 (1989). See also section 5-800, infra. 

In Metal Sales Mfg., 310 NLRB 597 (1993), the Board permitted the late filing of an

affidavit attesting to the dates the employees signed the showing of interest. 

5-200 Nature of Evidence of Interest 

324-4040-3300 et seq. 

324-8025 

590-7550 

The most commonly submitted type of evidence of interest consists of cards on which

employees apply for membership in the labor organization and/or authorize it to represent them. 

Cards which were neither applications for membership nor specific authorizations to 

represent, but merely asked the Board to conduct an election, were held to suffice as evidence of

interest when the cards stated that the purpose of seeking an election was for the union to be

certified. Potomac Electric Co., 111 NLRB 553, 554–555 (1955).

Other types of evidence of interest are also used, particularly when intervention is sought. 

Thus, a current contract constitutes evidence of interest. Brown-Ely Co., 87 NLRB 27 fn. 2 

(1950). A recently expired contract may also serve as such evidence. Bush Terminal Co., 121

NLRB 1170 fn. 1 (1958). Where a labor organization has a contract covering the employer’s

plant at another location and claims that the contract is applicable to the new plant, it has 

sufficient evidence of interest to warrant intervention. Intervention has also been granted based on 

agreements between the intervenors and a trade association that had been adopted by the 

employer in the proceeding, each signatory union being regarded as having “at least a colorable

interest in certain of the employees involved.’’ W. Horace Williams Co., 130 NLRB 223 fn. 2

(1961). 

It is clear, of course, that a contract found in an unfair labor practice proceeding to have been 

executed in violation of Section 8(a)(2) of the Act may not serve as evidence of interest. Bowman 

Transportation, 120 NLRB 1147 fn. 7 (1958); see also Halben Chemical Co., 124 NLRB 1431

(1959). 

5-210 Construction Industry 

In John Deklewa & Sons, 282 NLRB 1375 (1987), the Board announced new unfair labor 

practice rules with respect to 8(f) prehire agreements in the construction industry. The Board 

noted that the second proviso to Section 8(f) provides that these agreements do not bar an election 

petition, and held that during the term of an 8(f) agreement, no showing of interest is required for

an RM election petition filed by the signatory employer. The Board has decided to apply the same 

rule to an RC petition filed by the signatory union during the term of an 8(f) agreement or shortly 

after the expiration. Stockton Roofing Co., 304 NLRB 699 (1991). 

In Pike Co., supra, the Board determined that the numerical sufficiency of a showing of 

interest in the construction industry is based on the number of unit employees employed at the 

time the petition is filed. In doing so, the Board rejected a contention that the showing should be 

based on the number of employees eligible to vote under the formula announced in Steiny & Co.,

308 NLRB 1323 (1992), discussed in section 23-420, infra. 

For other construction industry issues see sections 9-211, 9-1000, 10-600–10-700, and 15-

130. 
SHOWING OF INTEREST 43

5-300 Designee 

324-8025-5000 

324-8075 

530-2075 

Issues are sometimes raised as to whether an authorization designating one labor organization 

may serve as valid evidence of interest for another. 

The general policy has been stated as follows: “The Board has always accepted showing-ofinterest cards designating a Labor Organization affiliated with . . . the labor organization 

appearing on the ballot.’’ New Hotel Monteleone, 127 NLRB 1092, 1094 (1960) (see also cases in 

fn. 6 of this decision), and Monmouth Medical Center, 247 NLRB 508 (1980). Note, however 

that in Woods Quality Cabinetry Co., 340 NLRB No. 163 (2003), the Board set aside an election

where the petitioner was incorrectly designated as an affiliate of the AFL–CIO. 

A designation of a parent organization is a valid designation of its affiliate. Thus, cards

designating the AFL–CIO have been held to be valid evidence of interest for an international

union affiliated with the AFL–CIO. Up-To-Date Laundry, 124 NLRB 247 (1959); see also 

McDonald Corp., 83 NLRB 427 fn. 2 (1949); General Shoe Corp., 113 NLRB 905, 905–906 

(1955). Similarly, cards designating an international have been accepted as valid evidence 

submitted by one of its locals. Norfolk Southern Bus Corp., 76 NLRB 488, 489–490 (1948). 

Designations of an organizing committee that was acting on behalf of the petitioner constitute 

valid evidence of interest on behalf of the latter. Cab Service & Parts Corp., 114 NLRB 1294

fn. 2 (1956). But see O & T Warehousing Co., 240 NLRB 386 (1979), in which the Board 

declined to place on the ballot “AFL–CIO and/or its Appropriate Affiliate,’’ requiring the parent

organization either to place itself on the ballot or designate a specific affiliate to appear on the 

ballot in advance of the election. 

Two or more labor organizations may join together to file a petition as joint petitioners or to 

intervene in a proceeding. Authorization cards designating only one petitioner are sufficient to

establish the interest of joint petitioners, and it is immaterial whether the cards indicate a desire

for joint or individual representation. “We are persuaded that when 30 percent of the employees

in a bargaining unit have indicated a desire to be represented by one or the other or two unions, 

and the two unions then offer themselves as joint representatives of the employees, the petitioning

unions have demonstrated enough employee interest in their attaining representative status to 

warrant holding an election.’’ St. Louis Packing Co., 169 NLRB 1106, 1107 (1968). See also

Mid-South Packers, 120 NLRB 495 fn. 1 (1958); Stickless Corp., 115 NLRB 979, 980 (1956). 

In such circumstances, the jointly acting labor organizations are jointly certified if successful

in the election, and the employer may then insist that they, in fact, bargain jointly for the 

employees in question in a single unit. Mid-South Packers, supra. If testimony at the hearing 

indicates that in fact the joint petitioners intervened to represent groups of employees separately,

the Board will dismiss the petition. Automatic Heating Co., 194 NLRB 1065 (1972); Suburban

Newspaper Publications, 230 NLRB 1215 (1977). 

For further discussion of joint representation see section 6-370, infra. 
44 SHOWING OF INTEREST 

5-400 Validity of Designations 

324-8025 

324-8075 

530-2075 

737-4267-7500 

Evidence of interest consisting of authorizations from employees must, of course, bear the

valid signatures of such employees. Signatures are presumed to be genuine unless there is some

indication to the contrary. 

An employee’s subjective state of mind in signing a union card cannot negate the clear

statement on the card that the signer is designating the union as that employee’s bargaining agent. 

Gary Steel Products Corp., 144 NLRB 1160 (1963). However, inducements offered to obtain 

authorizations may be brought into issue. In one case, the Board held that cards submitted by the 

petitioner, which had been signed by supporters of the incumbent union, were not invalid because 

solicited through appeals to sign to get an election, in which the petitioner’s literature clearly

reflected that the petitioner’s purpose in seeking such authorizations was to supplant the 

incumbent. Potomac Electric Co., 111 NLRB 553 (1955). These issues are not, as noted earlier, 

litigable. See CHM section 11028 et seq. for procedures for challenging showing. See also 

General Dynamics Corp., 213 NLRB 851, 853 (1974), concerning the appropriate timing of the 

challenge. 

Issues have arisen involving the validity of designations because of alleged supervisory 

participation in securing the showing of interest and allegations to that effect have been found 

meritorious where in fact such participation existed. Thus, when a supervisor participated in

obtaining the signatures of all the employees whose cards were submitted as evidence of interest,

the petition was dismissed. Southeastern Newspapers, 129 NLRB 311 (1961). In that case, the 

employer’s motion to dismiss was treated “as a request for administrative investigation of the

petitioner’s showing.’’ Cards signed at a meeting at which a supervisor vigorously espoused the 

petitioner’s cause were not counted as valid evidence of interest. Wolfe Metal Products Corp., 

119 NLRB 659 (1958). See also Desilu Productions, 106 NLRB 179 (1953). More recently, the 

Board has characterized this policy as a “bright line rule” of excluding all cards directly solicited 

by a supervisor. Dejana Industries, 336 NLRB 1202 (2001).

In Catholic Community Services, 254 NLRB 763 (1981), the Board found no supervisory

taint when supervisors and unit employees signed a letter endorsing the need for a union and an 

alleged supervisor sat at petitioner counsel’s table during the representation hearing. In a 

decertification proceeding, where the supervisor is a member of the bargaining unit and there is

no showing that his/her solicitation of the showing of interest was at the behest of the employer, 

the Board will not find taint of the showing of interest. Los Alamitos Medical Center, 287 NLRB 

415, 417 (1987). 

In a case which the Regional Director referred to the Board for an administrative 

determination of a showing of interest, the Board found that the individual alleged to have 

participated in obtaining all the authorization cards was not a supervisor within the meaning of 

the Act “during the period in which the authorization cards were solicited,’’ and consequently his 

participation did not taint or otherwise cast a doubt on the uncoerced nature of the showing of

interest. L. A. Benson Co., 154 NLRB 1371 (1965). See also Silver Spur Casino, 270 NLRB 

1067 (1984).

See also sections 24-110 and 24-328 for discussion of supervisory solicitation of support for

union as objectionable conduct. 

A showing of interest is not subject to attack on the ground that the cards on which it is based

have been revoked or withdrawn. “Such an attack,’’ said the Board, “has no bearing on the 

validity of the original showing but merely raises the question as to whether particular employees
SHOWING OF INTEREST 45

have changed their minds about union representation. That question can best be resolved on the 

basis of an election by secret ballot.’’ General Dynamics Corp., 175 NLRB 1035 (1969). See also

Allied Chemical Corp., 165 NLRB 235 fn. 2 (1967); Vent Control, Inc., 126 NLRB 1134 

(1960). 

Cards signed for more than one labor organization may be counted in determining showing of 

interest. “There is no reason why employees, if they so desire, may not join more than one labor 

organization.’’ The election will determine which labor organization, if any, the employees wish

to represent them. Brooklyn Gas Co., 110 NLRB 18, 20 (1955). 

5-500 Currency and Dating of Designations 

324-8050 

530-2075-6700 

The general rule is that the individual authorization must be dated and must be current. A. 

Werman & Sons, 114 NLRB 629 (1956). The requirement for dating the showing may be 

accomplished by affidavit either submitted with the showing itself or timely filed thereafter. Dart 

Container Corp., 294 NLRB 798 (1989). See also Metal Sales Mfg., 310 NLRB 597 (1993), 

where the Board permitted the late filing of an affidavit attesting to the dates of the showing. 

Questions have arisen, however, as to what is meant by “current.’’ Thus, it has been held that

cards dated more than a year prior to the filing of the petition were sufficiently current. Carey 

Mfg. Co., 69 NLRB 224 fn. 4 (1946); see also Northern Trust Co., 69 NLRB 652 fn. 4 (1946)

(10 months). Evidence of interest submitted in a prior Board proceeding which had been 

withdrawn was held to be valid evidence of interest in a new case more than 2 months later.

Cleveland Cliffs Iron Co., 117 NLRB 668 (1957); see also Knox Glass Bottle Co., 101 NLRB 36

fn. 1 (1953). However, cards dated prior to a state-conducted election, which had been lost by the 

petitioner 3 months prior to the Board proceeding, were held to be insufficient evidence of 

interest. King Brooks, Inc., 84 NLRB 652, 652–653 (1949). In Big Y Foods, 238 NLRB 855 fn. 4 

(1978), a contention that the showing of interest was stale was rejected when the delay in

processing the petition to an election was attributable to the employer’s unfair labor practices. 

Similarly, the Board rejected a suggestion that a new showing be made because of a lapse of time

and turnover among employees between the first and directed second election. Sheraton Hotel 

Waterbury, 316 NLRB 238 (1995). See also Freund Baking Co., 330 NLRB 17 (1999).

Under certain circumstances, labor organizations are permitted to intervene after the close of 

the hearing. However, they must meet the requirements for an intervenor’s showing of interest as 

of the time of the hearing in the case. Gary Steel Products Corp., 127 NLRB 1170 fn. 3 (1960); 

see also Transcontinental Bus System, 119 NLRB 1840 fn. 3 (1958); United Boat Service Corp.,

55 NLRB 671 (1944). See also Crown Nursing Home Associates, 299 NLRB 512 (1990). 

5-600 Quantitative Sufficiency 

324-0187 

324-4020 

As already indicated, a showing of 30 percent of the employees in the appropriate unit is

normally required of a petitioner. Pearl Packing Co., 116 NLRB 1489, 1489–1490 (1957); see 

also S. H. Kress & Co., 137 NLRB 1244, 1249 (1962). 

The Board has rejected contentions that a larger showing of interest should be required when 

the petitioner has previously lost several elections. Sheffield Corp., 134 NLRB 1101 fn. 4 (1962); 

Barber-Colman Co., 130 NLRB 478 fn. 3 (1961). When cards attacked because of alleged 

unreliability are insufficient in number to reduce a petitioner’s showing of interest to less than 30 

percent, the showing is accepted as adequate. Pearl Packing Co., supra. 

A showing of interest of less than 30 percent was found to be adequate in which (1) the 

petitioner had represented most of the classifications in the requested unit for 20 years; (2) its last
46 SHOWING OF INTEREST 

contract had contained a valid union-security provision requiring the employees to become and 

remain members; and (3) the Board, in refusing to resolve the unit issues pursuant to a motion for 

clarification, had already advised the petitioner that it would entertain a petition for certification. 

FWD Corp., 138 NLRB 386 (1962) (see also cases cited in fn. 3 of this decision). 

Board practice does not require a new showing of interest in the case of expanding units. 

Avondale Shipyards, 174 NLRB 73 (1969). 

No evidence of interest is required when the labor organization seeks to add employees to an

existing certified unit as an accretion to such unit. Kennametal, Inc., 132 NLRB 194 fn. 4 (1961).

In Duke Power Co., 191 NLRB 308, 311 fn. 10 (1971), the Board held that there is no 

requirement that the employees’ interest in decertification be expressed on the Board’s standard

forms. 

A change in ownership of the employer during the organizing campaign does not require a 

new showing of interest. New Laxton Coal Co., 134 NLRB 927 (1961). 

5-610 No Showing of Interest in 8(b)(7)(C) Cases 

578-8075-6056 

Despite the statutory provision noted above requiring that the petition be supported by a

substantial number of employees, Section 8(b)(7)(C) of the Act provides that, when a petition is

filed in conjunction with an unfair labor practice charge alleging a violation of this section, the 

Board shall direct an election in the appropriate unit without regard to the absence of a showing 

of substantial interest. Accordingly, in these circumstances, no showing of interest is required. 

See section 7-150 for further information. 

5-620 A Specific 30-Percent Requirement in UD Cases 

324-4060-5000 

On the other hand, Section 9(e)(1) of the Act establishes a specific 30-percent requirement in

support of petitions to rescind a labor organization’s authority to enter into collective-bargaining 

contracts requiring membership in the union as a condition of employment, as set forth in Section

8(a)(3) of the Act. 

5-630 Employer Petitions 

316-6725 

324-4020-5000 

When the petition is filed by an employer, pursuant to Section 9(c)(1)(B) of the Act, no 

evidence of representation on the part of the labor organization claiming a majority is required. 

Felton Oil Co., 78 NLRB 1033, 1035–1036 (1948). This is true of any intervenor claiming to

represent a majority of the employees in the unit involved in the petition. See also General 

Electric Co., 89 NLRB 726, 726–727 (1950). It is also true even if the employer seeks to 

withdraw its petition but a union claiming to represent a majority in the unit desires an election. 

International Aluminum Corp., 117 NLRB 1221 (1957). 

See also discussions of 8(f) agreements under section 5-210 in this chapter, supra. 

5-640 Showing of Interest for Intervention 

324-4040 

Administratively, the Board has adopted the following policies with respect to the showing of

interest of intervenors: 

(a) If an intervenor has less than a 10-percent showing of interest and the other parties 

are willing to consent to an election, the consent-election agreement is approved, and the 

intervenor has the right to appear as a choice on the ballot. 
SHOWING OF INTEREST 47

(b) If an intervenor has more than a 10-percent showing and is unwilling to consent to 

an election, even though the other parties are willing, a consent-election agreement will not 

be approved, and the matter must go to hearing (unless dismissal is required by some other 

factor). 

(c) “Intervention’’ based on more than 30-percent showing amounts to a cross-petition 

which permits the union to seek a unit differing in substance from that of the original 

peitition. 

An intervenor seeking a unit different from that sought by the petitioner must make a 

petitioner’s showing of interest in the unit it seeks. Great Atlantic & Pacific Tea Co., 130 NLRB 

226, 226–227 (1961). 

When the petitioner sought an election in a single unit of employees in two departments and

the intervenor sought to represent the employees in separate departmental units, but the intervenor 

had failed to make the necessary 30-percent showing among the employees in either department,

the Board did not direct elections in separate units, but placed the intervenor’s name on the ballot

in the overall unit since it had made some showing of interest among the employees sought. 

Southern Radio & Television Equipment Co., 107 NLRB 216, 216–217 (1954). When 

intervention was sought for the purpose of securing a separate election in a craft unit, severing it

from an existing larger unit, the union was required to make a 30-percent showing of interest in

the craft unit. Boeing Airplane Co., 86 NLRB 368 (1949). 

If the petitioner lacks a sufficient interest in a unit found appropriate, but an intervenor 

possesses a petitioner’s interest and wishes to proceed to an election, the petition will not be

dismissed, nor will a withdrawal request be granted, but the intervenor will be treated as a crosspetitioner. Borden Co., 120 NLRB 1447, 1449 (1958); Seaboard Machinery Corp., 98 NLRB 

537 (1951). In such circumstances, the petitioner may be placed on the ballot as a choice in any

unit in which it has some evidence of interest, but may not be on the ballot for any unit in which it 

has no evidence of interest. Borden Co., supra. 

In Crown Nursing Home Associates, 299 NLRB 512 (1990), the Board held that an 

intervenor has the right to make an additional showing of interest when the original petitioner 

sought to withdraw because another incumbent union had served a contract. The additional

showing was required to be submitted timely but was not required to predate the execution of the 

contract. 

See also section 3-830, supra. 

5-700 Relation to Bargaining Unit 

In all cases, the showing of interest must relate to the bargaining unit involved. Esso Standard 

Oil Co., 124 NLRB 1383, 1385 (1959).

5-800 Date for Computation 

324-4090 

It is apparent that the computation as to the showing of interest must be made at some certain

date or dates. Normally, this is as of the date the petition was filed, or the showing may be 

computed from the payroll period immediately preceding the filing of the petition. Brunswick

Quick Freezer, 117 NLRB 662 (1957). This is true even in industries when there is fluctuating

employment. Higgins, Inc., 111 NLRB 797 fn. 2 (1955); Trenton Foods, 101 NLRB 1769 (1953). 

When the unit found appropriate differs from that sought and a new check of the showing of

interest is necessary, the Union may be given reasonable time to procure additional showing of

interest. CHM section 11031.2. See also Brown Transport Corp., 296 NLRB 1213 (1989); 

Casale Industries, 311 NLRB 951 (1993); and Alamo Rent–A–Car, 330 NLRB 897, 899 fn. 9 

(2000).

In seasonal industries, the showing of interest may be made as of the time of filing the

petition, even though the number of employees at such time is only a small percentage of the 
48 SHOWING OF INTEREST 

complement at the seasonal peak. J. J. Crosetti Co., 98 NLRB 268 fn. 1 (1951). If there are no

employees employed at the time of filing the petition, the showing of interest may be made 

among the employees of the previous season if it is expected that they will be recalled during the 

new season. Grower-Shipper Vegetable Assn., 112 NLRB 807 (1955); cf. Holly Sugar Corp., 94 

NLRB 1209 (1951). In a seasonal industry, a significant rate of reemployment will permit the use 

of the previous periods showing of interest. Bogus Basin Recreation Assn., 212 NLRB 833

(1974). 

Unusual circumstances occasionally require a different policy. Thus, when the petition was 

prematurely filed (in a nonseasonal industry) and a later election was directed, a current showing 

of interest was required. Mrs. Tucker’s Products, 106 NLRB 533, 535 (1953). When the 

petitioner had been found in an unfair labor practice proceeding to have received employer

assistance in violation of Section 8(a) (2), an adequate showing of interest had to be made with 

cards obtained after the petitioner’s illegal status as the representative of the employees had been 

“effectively cut off.’’ Halben Chemical Co., 124 NLRB 1431 (1959). See also Bowman 

Transportation, 120 NLRB 1147, 1150 fn. 7 (1958); and Share Group, Inc., 323 NLRB 704

(1997). 

In Gaylord Bag Co., 313 NLRB 306 (1993), the Board restated its rule that the showing was 

not litigable. In reviewing the Regional Director’s objections determination the Board assumed

that a contention concerning the showing was timely and went on to conclude that the showing

was adequate even assuming the employer’s contentions were correct. Thus, the Board noted that 

even discounting the cards of employees allegedly affected by the union’s conduct, there were 

sufficient remaining cards to satisfy the showing. It is important to note here that the Board’s 

discussion of the adequacy of the showing was not essential to its determination of the case

because as the Board noted “after the election the adequacy of the showing is irrelevant.’’ See

also City Stationery, Inc., 340 NLRB No. 70 (2003). 

5-900 Investigations of Showing of Interest 

324-2000 

393-6814 

530-2075-6767 

737-2850-9900 

“An integral and essential element of the Board’s showing-of-interest rule is the 

nonlitigability of a petitioner’s evidence as to such interest. The Board reserves to itself the 

function of investigating such claims, and in its investigation it endeavors to keep the identity of

the employees involved secret from the employer and other participating labor organizations. . . .

The Board’s requirement that petitions be supported by a 30-percent showing of interest gives 

rise to no special obligation or right on the part of employers.’’ S. H. Kress & Co., 137 NLRB 

1244, 1248–1249 (1962). 

In keeping with these policies, a hearing officer is barred by the Board’s Rules and 

Regulations from producing the evidence of interest. Plains Cooperative Oil Mill, 123 NLRB 

1709, 1711 (1959), and the Board refused to supply cards in response to a subpoena. Irving v. 

DiLapi, 600 F.2d 1027 (2d Cir. 1979). The manner, method, and procedure in determining the 

showing of interest is not for disclosure. Pacific Gas & Electric Co., 97 NLRB 1397 fn. 3

(1951). In Smith’s Food & Drug Centers, 320 NLRB 844 (1996), the Board, on review, found 

sufficient evidence of lack of a showing of interest to dismiss the petition without a remand to the 

Regional Director. 

When a party contends that a showing of interest was obtained by fraud, duress, or coercion, 

the proper procedure is to submit to the Regional Director any proof it might have. Perdue 

Farms, Inc., 328 NLRB 909 (1999); and Pearl Packing Co., supra. See also Columbia Records, 

125 NLRB 1161 (1960); and Waste Management of New York, 323 NLRB 590 (1997). Such
SHOWING OF INTEREST 49

conduct may also be considered as objectionable. See St. Peter More-4, 327 NLRB 878 (1999),

and Millsboro Nursing & Rehabilitation Center, 327 NLRB 879 (1999). Similarly, any attack on 

the genuineness of signatures should be made by submitting available evidence to the Regional 

Director within 5 days after the close of the hearing. Georgia Kraft Co., 120 NLRB 806 (1958);

Phillips Petroleum Co., 130 NLRB 895 fn. 2 (1961). See also Tung-Sol Electric, 120 NLRB 

1674, 1678 (1958). See also CHM section 11028.1, et seq. 

When evidence is submitted to the Regional Director which gives reasonable cause for 

believing that the showing of interest may have been invalidated by fraud or otherwise, an 

administrative investigation will be made. See, for example, Perdue Farms, supra; Globe Iron 

Foundry, 112 NLRB 1200 (1955); Georgia Kraft Co., supra. However, an administrative

investigation will not be made unless the allegations of invalidity are accompanied by supporting 

evidence. Goldblatt Bros., 118 NLRB 643 fn. 1 (1957). Thus, affidavits by more than 70 percent 

of the unit to the effect that the affiants had not authorized the petitioner to represent them

warranted an administrative investigation. Globe Iron Foundry, supra. Compare General Shoe

Corp., 114 NLRB 381, 382–383 (1956), in which such denials were from less than 70 percent of

the unit. 

A request for a check of the showing to determine its quantative sufficiency must be made

timely, viz. “only at or around the petition is filed” Community Affairs, Inc., 326 NLRB 311

(1998). 

The above administrative procedures parallel, but do not impinge on, the general rule that the

Board normally refuses to receive evidence in representation cases that signatures on cards were 

unlawfully obtained or were otherwise invalid or fraudulent, but that such issues may be litigated,

on appropriate charges and a complaint, in an unfair labor practice proceeding. Dale’s Super 

Valu, 181 NLRB 698 (1970). See also Radio Corp. of America, 89 NLRB 699 fn. 5 (1950); White

River Lumber Co., 88 NLRB 158 fn. 3 (1950); Clarostat Mfg. Co., 88 NLRB 723 fn. 2 (1950).