(1) An initial investigation is a review of a reported heating oil tank release by the agency and documentation of reported conditions. The purpose of the initial investigation is to determine:

(a) Whether there has been a release from a heating oil tank that may pose a threat to human health or the environment;

(b) Whether further remedial action is necessary to confirm the release or to address the threat posed by the release under MTCA to protect human health and the environment;

(c) Whether emergency remedial action is necessary to confirm the release or to address the threat posed by the release; and

(d) Whether referral to another authority is appropriate.

(2) The agency will complete an initial investigation unless:

(a) The circumstances associated with the suspected or confirmed release are known to the agency and have previously been, or are currently being, evaluated by the agency or other government agency; or

(b) The agency does not have a reasonable basis to believe that there has been a release or threatened release of a hazardous substance that may pose a threat to human health or the environment.

(3) The agency will complete an initial investigation within 90 days of a release being reported to the agency.

(4) The agency may rely on another government agency or a contractor to the agency to conduct an initial investigation on its behalf, provided the agency determines:

(a) The other agency or contractor is not suspected to have contributed to the release of heating oil; and

(b) The other agency or contractor has no conflict of interest.

(5) Within 30 days of completing an initial investigation of a release, the agency will conduct additional investigation or make one of the following determinations:

(a) No release of heating oil occurred.

(b) A release of heating oil occurred but does not pose a threat to human health or the environment requiring remedial action under MTCA.

(c) A release of heating oil occurred that posed a threat to human health or the environment, a remedial action to address the threat has been completed, and no further remedial action is necessary to address the threat.

(d) A release of heating oil occurred that poses a threat to human health or the environment and further remedial action other than emergency remedial action is necessary to address the threat. The agency will notify the owner and operator and the department of ecology of the agency's determination.

(e) A release of heating oil occurred that poses a threat to human health or the environment and an emergency remedial action is necessary to address the threat. The agency will notify the owner and operator and the department of ecology of the agency's determination.