(1) This chapter applies to all sites where there has been a release or threatened release of a hazardous substance that may pose a threat to human health or the environment. Under this chapter, ecology may require or take those actions necessary to investigate and clean up these releases.

(2) Ecology retains all its authority to address a release or threatened release under other applicable laws or regulations. The cleanup process and procedures under this chapter and under other laws may be combined. Ecology may initiate a remedial action under this chapter and may upon further analysis determine that another law is more appropriate, or vice versa.

(3) If a hazardous substance remains at a site after actions have been completed under other applicable laws or regulations, ecology may apply this chapter to protect human health or the environment.