1. (a) TRE and TIE. A TRE is required when persistent toxicity is demonstrated. When intermittent toxicity is demonstrated DEQ may require a TRE/TIE.
2. (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 252:606-6-27 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.
3. (c) Effective date of WET limit. The effective date of a WET limit or a chemical-specific limit may be deferred up to three 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 year from the date of completion of the TRE/TIE or the effective date of a permit, as applicable.

Added at 41 Ok Reg, Number 23, effective 9-15-24