19 USC 2413 - Consultation upon initiation of investigation

(a) In general 

(1) On the date on which an investigation is initiated under section 2412 of this title, the Trade Representative, on behalf of the United States, shall request consultations with the foreign country concerned regarding the issues involved in such investigation.
(2) If the investigation initiated under section 2412 of this title involves a trade agreement and a mutually acceptable resolution is not reached before the earlier of
(A) the close of the consultation period, if any, specified in the trade agreement, or
(B) the 150th day after the day on which consultation was commenced,

the Trade Representative shall promptly request proceedings on the matter under the formal dispute settlement procedures provided under such agreement.

(3) The Trade Representative shall seek information and advice from the petitioner (if any) and the appropriate committees established pursuant to section 2155 of this title in preparing United States presentations for consultations and dispute settlement proceedings.
(b) Delay of request for consultations 

(1) Notwithstanding the provisions of subsection (a) of this section
(A) the United States Trade Representative may, after consulting with the petitioner (if any), delay for up to 90 days any request for consultations under subsection (a) of this section for the purpose of verifying or improving the petition to ensure an adequate basis for consultation, and
(B) if such consultations are delayed by reason of subparagraph (A), each time limitation under section 2414 of this title shall be extended for the period of such delay.
(2) The Trade Representative shall
(A) publish notice of any delay under paragraph (1) in the Federal Register, and
(B) report to Congress on the reasons for such delay in the report required under section 2419 (a)(3) of this title.