Indiana Code Title 13. Environment § 13-25-2-18

Sec. 18. (a) A court, in issuing a final order in an action brought under section 15, 16, or 17 of this chapter, may award costs of litigation, including reasonable attorney's fees and expert witness fees, to the prevailing or the substantially prevailing party if the court determines that the award is appropriate.

(b) Sections 15, 16, and 17 of this chapter do not restrict or expand any right that a person may have under federal or state law to seek enforcement of a requirement or to seek other relief.

(c) In an action brought under section 15, 16, or 17 of this chapter, the state, if the state is not a party, may intervene as a matter of right.

(d) In an action brought under section 15, 16, or 17 of this chapter, a person may intervene as a matter of right if:

unless the state shows that the person's interest is adequately represented by existing parties to the action.