(1) Purpose. The purpose of the PBT list is to identify toxic chemicals that require further action because they remain ("persist") in the environment for long periods of time where they can bioaccumulate to levels that pose threats to human health and environment in Washington.

(2) Intended uses of the PBT list. Ecology will use the PBT list in the following ways:

(a) Chemical action plans. To select chemicals for chemical action plan development.

(b) Ambient monitoring. To help guide decisions on the design and implementation of ecology programs for characterizing chemical concentrations in the ambient environment.

(c) Biomonitoring. To encourage and inform the department of health regarding their efforts to monitor chemicals in human tissue.

(d) Public awareness. To promote greater public awareness on the problems associated with PBT chemicals, the uses and sources of individual PBTs and steps that individuals and organizations can take to reduce PBT uses, releases and exposure.

(e) Voluntary measures. To help identify opportunities for government agencies, businesses and individuals to implement voluntary measures for reducing and phasing out PBT uses and releases.

(3) Relationship to actions addressing chemical uses and releases. Ecology has determined that the chemicals on the PBT list pose a potential threat to human health and the environment in Washington.

(a) Ecology's decision to include a particular chemical on the PBT list does not represent a final determination that all uses and releases of that chemical should be reduced and phased-out. Any recommendations on uses and releases of a particular chemical will be made in the CAP process.

(b) Ecology will not use the PBT list as the sole basis for establishing discharge monitoring requirements that are not required under current permits. Ecology will evaluate and, if necessary, prepare recommendations for additional monitoring requirements when preparing chemical action plans (WAC 173-333-420 and 173-333-430).