Owners and operators must respond to spills and overfills of regulated substances in accordance with the requirements of this section.

(1) If a spill or overfill of regulated substances from an UST system results in a release that may pose a threat to human health or the environment, including in the following cases, then the release must be reported, investigated, and cleaned up in accordance with WAC 173-360A-0750:

(a) A spill or overfill of petroleum results in a release to the environment of more than twenty-five gallons, a sheen on surface water, or groundwater contamination; or

(b) A spill or overfill of a hazardous substance results in a release to the environment of more than the reportable quantity specified in 40 C.F.R. Sec. 302.

(2) If a spill or overfill of regulated substances from an UST system does not result in a release or results in a release that does not pose a threat to human health or the environment, then the spill or overfill must be:

(a) Immediately contained and cleaned up as follows:

(i) Eliminate or reduce any fire, explosive, or vapor hazards resulting from the spill or overfill, and do so in a manner that minimizes the release of regulated substances into the environment;

(ii) Prevent the release or further release of regulated substances into the environment and the migration of any substances already released;

(iii) Absorb or otherwise contain any free product and properly dispose of the product and any used absorbent materials in accordance with all applicable federal, state, and local requirements. Free product must not be flushed into storm drains, catch basins, dry wells, monitoring wells, or other locations with a possible connection to surrounding soils, groundwater, or surface water; and

(iv) Provide for the proper disposal or treatment of any contaminated soils in accordance with applicable federal, state, and local requirements; and

(b) Reported to the department within twenty-four hours if the cleanup required under (a) of this subsection has not been completed.