(a) This section applies to a transportation project that is a state transportation project or an FHWA transportation project, except that subsection (h) of this section applies only if the project is an FHWA transportation project.
(b) A DEIS, FEIS, or supplemental EIS may be supplemented at any time. An EIS will be supplemented if the department delegate determines that:
  (1) changes to the project would result in significant environmental impacts that were not evaluated in the EIS; or
  (2) new information or circumstances relevant to environmental concerns and bearing on the project or its impacts would result in significant environmental impacts not evaluated in the EIS.
(c) A supplemental EIS will not be necessary if:
  (1) the changes to the project, new information, or new circumstances result in a lessening of adverse environmental impacts evaluated in the EIS without causing other environmental impacts that are significant and were not evaluated in the EIS; or
  (2) the department delegate decides to approve an alternative fully evaluated in an approved final EIS but not identified as the preferred alternative, in which event a revised ROD will be prepared and circulated in accordance with §2.84 of this subchapter (relating to Environmental Impact Statements) and §2.108 of this subchapter (relating to Notice of Availability).
(d) If the department delegate is uncertain of the significance of the new impacts, the project sponsor will develop appropriate environmental reports or, if the department delegate considers appropriate, an EA to assess the impacts of the changes, new information, or new circumstances. If, based on the studies, the department delegate determines that a supplemental EIS is not necessary, the department delegate must indicate that determination in the project file.
(e) To the extent of the significant new impact, a supplement is to be developed using the same process and format (i.e., DEIS, FEIS, and ROD) as an original EIS, except that scoping is not required.
(f) In some cases, a supplemental EIS may be required to address issues of limited scope, such as the extent of proposed mitigation or the evaluation of location or design variations for a limited portion of the overall project. In such an event, the preparation of a supplemental EIS does not necessarily:
  (1) prevent the granting of new approvals;
  (2) require the withdrawal of previous approvals; or
  (3) require the suspension of any project activities not directly affected by the supplement.
(g) If the changes in question are of such a magnitude as to require a reassessment of the entire project, or more than a limited portion of the overall project, the department delegate will suspend any activities that would have an adverse environmental impact or limit the choice of reasonable alternatives, until the supplemental EIS is completed.
(h) For an FHWA transportation project, in addition to the requirements of subsections (a) - (g) of this section, the department delegate and project sponsor must comply with any federal laws, including FHWA's rules, applicable to the processing of the supplemental EIS. If federal law, including FHWA's rules, conflicts with this chapter, federal law controls to the extent of the conflict. At the conclusion of technical review, the department delegate will forward the environmental review document and any other relevant documentation to FHWA with an appropriate recommendation.

Source Note: The provisions of this §2.86 adopted to be effective April 16, 2012, 37 TexReg 1727; amended to be effective April 16, 2014, 39 TexReg 2941