TREs, TIEs and WET limits

(a) TRE and TIE. A TRE is required when persistent toxicity is demonstrated. When intermittent toxicity is demonstrated DEQ may require a TRE/TIE. (b) WET limits. DEQ shall incorporate a WET limit into a permit for the species affected by whole effluent toxicity upon the completion of a TRE /TIE, unless DEQ determines that chemical- specific effluent limits or toxicity-specific management practices in accordance with OAC 252:690-3-27 are sufficient to comply with the narrative toxicity criterion and protect the designated use. DEQ may also incorporate a WET limit or chemical-specific effluent limits into a permit when reasonable potential is established. (c) Effective date of WET limit. The effective date of a WET limit or a chemical-specific limit may be deferred up to three (3) years from the date of completion of the TRE /TIE or the effective date of a permit, as applicable. The effective date of toxicity-specific management practices may be deferred up to one (1) year from the date of completion of the TRE /TIE or the effective date of a permit, as applicable.