19 CFR §220.7

1. (a)In general. A petition will not be considered to be properly filed unless the petition and the Commission disclosure form are filed in accordance with and contain the information required by §§ 220.3 through 220.5
2. (b)Identical and overlapping petitions.
   1. (1)A petition will not be considered to be properly filed if the petitioner has previously filed, and has not withdrawn, a petition for duty suspension or reduction during the current filing cycle:
      1. (i)For an article that is identical to that in the current petition;
      2. (ii)For an article whose article description includes the article covered by the current petition; or
      3. (iii)For an article that is included in the scope of the current petition.
   2. (2)Should the Commission find that a petitioner has filed one or more identical or overlapping petitions and that such earlier filed petitions have not been withdrawn, the Commission will generally consider the earliest filed pending petition to be the petition of the petitioner.