The applicability of U.S. EPA's Spill Prevention, Control and Countermeasures (SPCC) rule, found at 40 CFR 112, is based upon two criteria:
1. The first criterion is the determination of whether a discharge of oil, in harmful quantities, can potentially occur into or upon navigable waters of the United States. Navigable waters are broadly defined to include waterways, swamps, lowlands, intermittent ditches, and storm and sanitary sewers.
2. The second criterion is the determination of whether the specified oil storage capacity volumes are exceeded. These volumes are as follows:
a. Greater than 42,000 gallons underground oil storage capacity; or
b. Greater than 1,320 gallons combined aboveground oil storage capacity in quantities greater than or equal to 55 gallons.
An SPCC Plan must be developed if both the discharge potential criterion and quantity criterion are met.
Many EHS professionals are aware of the oil storage capacity criterion (1,320 gallons) for aboveground storage, but how often does the buried storage capacity of 42,000 gallons actually trigger the need for an SPCC plan?
The answer to this question is that it rarely happens. Most SPCC plans are triggered by a facility’s aboveground storage capacity of 1,320 gallons or more of oil.
The reason for this is because underground storage tanks (UST’s) are governed by their own regulations (40 CFR 280 and 281). These UST regulations require owners and operators of tanks in the ground to prevent, detect, and clean up releases. Since the UST’s are already governed by their own set of rules, there is no reason for them to be governed by two programs.
The location and capacity of 40 CFR 280 and 281 regulated UST’s still need to be marked on the SPCC facility diagram as per SPCC regulations 40 CFR 112.7(a)(3), but they do not need to be noted anywhere else in the plan including the SPCC applicability calculations.
There is one wrinkle to UST’s as defined by the UST regulations compared to the SPCC definition. The UST rule defines underground tanks as having 10% or greater of its volume underground but the SPCC regulations consider anything that is not completely buried to be above ground storage tanks. So a tank needs to have 100% of its volume underground to be considered a UST under the SPCC rule.
Because of this, there is the chance that a tank already covered by the UST regulations could still be subject to the SPCC rule. Even though a tank would be considered a UST as defined by the UST regulations and therefore be exempt from SPCC regulations, it would be considered an aboveground tank according to SPCC regulations, would be subject to the SPCC rule, and must be included when calculating the aboveground storage capacity.