For purposes of using the higher EPCRA gasoline and diesel fuel thresholds, when is a retail gas station considered "not in compliance" with UST requirements?

A facility is not in compliance with the UST requirements (and therefore not eligible for the higher EPCRA thresholds) when it first fails to meet the UST requirements. For example, if an owner or operator of a retail gas station has a tank system that was not in compliance with UST requirements that went into effect in December of 1998 (see 40 CFR 280.21(a) and 281.31), that owner or operator can not apply the higher thresholds.