19 CFR §206.42

1. (a)A petition under section 406(a) of the Trade Act may be filed by an entity, including a trade association, firm, certified or recognized union, or group of workers, that is representative of a domestic industry producing an article with respect to which there are imports of a like or directly competitive article which is the product of a Communist country, which imports, allegedly, are increasing rapidly, either absolutely or relative to domestic production, so as to be a significant cause of material injury, or the threat thereof, to such domestic industry.
2. (b)A petition under section 421(b) or (o) of the Trade Act may be filed by an entity, including a trade association, firm, certified or recognized union, or group of workers, which is representative of an industry.