Indiana Code Title 13. Environment § 13-14-9-12

(1) The board determines that necessary amendments to the proposed rule will affect persons that reasonably require an opportunity to comment under section 4 of this chapter.

(2) The board determines that due to the fundamental or inherent structure or content of the proposed rule, the only reasonably anticipated method of developing a rule acceptable to the board is to require the department to redraft the rule and to obtain public comments under section 4 of this chapter.

(3) The board determines that, due to a procedural or other defect in the implementation of applicable rulemaking requirements, an interested or affected party will be unfairly and substantially prejudiced if the public comment period under section 4 of this chapter is not again afforded and that no reasonable alternative method to obtain public comments is available to the interested or affected party other than the public comment period under section 4 of this chapter.