1. (1) If only the routine compliance monitoring toxicity test which initiated the additional monitoring described in WAC 173-205-090 fails the compliance test, then the toxicity can be considered as transient and the discharger shall:

   1. (a) Search all recent facility records which might explain the transient toxicity (operating records, monitoring results, inspection records, spill reports, weather records, production records, etc.); and
   2. (b) Submit a report to the department on the possible causes and preventive measures for the transient toxicity within thirty days of the last additional sample.

2. (2) If any toxicity test fails the compliance test described in WAC 173-205-070 during the additional monitoring conducted in accordance with WAC 173-205-090(1), then the permittee shall submit a plan to the department within sixty days of the last additional sample for a toxicity identification/reduction evaluation.

   1. (a) As a part of this plan, the permittee may request that the department allow up to six months before beginning the investigation outlined in the EPA manuals for facility personnel to attempt to control the most likely sources of toxicity through efforts such as changes in plant operation, replacement of a toxic material used in the facility, or improvement of best management practices.

      1. (i) The department shall approve the request in writing.
      2. (ii) The department approval may be sent to the permittee before completion of the review of the toxicity identification/reduction evaluation plan.

   2. (b) The toxicity identification/reduction evaluation plan shall be based on procedures in the latest versions of the EPA guidance documents for conducting toxicity reduction evaluations or toxicity identification evaluations.

      1. (i) The toxicity identification/reduction evaluation plan need not include any procedure from the EPA manuals that is not necessary to the goal of controlling the discharge of whole effluent toxicity by the permittee.
      2. (ii) The department may approve any modifications or additions to the EPA procedures that will improve the ability to identify or reduce toxicity.
   3. (c) The permittee shall submit to the department a toxicity identification/reduction evaluation plan revised in accordance with department comments within thirty days after receipt of department comments.
3. (3) The permittee shall implement the toxicity identification/reduction evaluation plan immediately upon notification by the department of plan approval.

4. (4) The department may allow a reduction in compliance monitoring for whole effluent toxicity limits during a toxicity identification/reduction evaluation if:

   1. (a) Effluent toxicity is being regularly measured and reported to the department; and
   2. (b) The department determines that the toxicity identification/reduction evaluation is being conducted in a timely manner.

[Statutory Authority: Chapter 90.48 RCW and 40 C.F.R. 122.44. WSR 93-20-110 (Order 91-54), § 173-205-100, filed 10/6/93, effective 11/6/93.]