Means either of the following:
a. There is indication that a tank system or dispensing system has leaked — such as inventory losses; observable free product or evidence of free product in secondary containment at dispensers, submersible pumps or spill buckets; petroleum odors; unexplained presence of water in a tank; or activation of a leak detection alarm system — but there is no observable environmental evidence of a release.
b. There is observable environmental evidence of a release, such as soil discoloration or free product, but the source is unknown.
Note: See subsection (62) for a definition of “leak,” subsection (76) for a definition of “obvious release” and subsection (103) for a definition of “release.”