29 CFR 401.10: Labor organization engaged in an industry affecting commerce.

A labor organization shall be deemed to be engaged in an industry affecting commerce if it:

(a) Is the certified representative of employees under the provisions of the National Labor Relations Act, as amended, or the Railway Labor Act, as amended; or

(b) Although not certified, is a national or international labor organization or a local labor organization recognized or acting as the representative of employees of an employer or employers engaged in an industry affecting commerce; or

(c) Has chartered a local labor organization or subsidiary body which is representing or actively seeking to represent employees of employers within the meaning of paragraph (a) or (b) of this section; or

(d) Has been chartered by a labor organization representing or actively seeking to represent employees within the meaning of paragraph (a) or (b) of this section as the local or subordinate body through which such employees may enjoy membership or become affiliated with such labor organization; or

(e) Is a conference, general committee, joint or system board, or joint council, subordinate to a national or international labor organization, which includes a labor organization engaged in an industry affecting commerce within the meaning of any of the preceding paragraphs of this section, other than a State or local central body.