Indiana Code Title 13. Environment § 13-11-2-242.3

Sec. 242.3. “Upset”, for purposes of IC 13-18-12-8, means an exceptional incident in which there is unintentional and temporary noncompliance with technology-based permit effluent limitations because of factors beyond the reasonable control of the permittee, and does not include noncompliance to the extent caused by operational error, improperly designed treatment facilities, inadequate treatment facilities, lack of preventive maintenance, or careless or improper operation.