Storage Tank Financial Responsibility Requirements

Table outlines Aboveground Storage Tank (AST) and Underground Storage Tank (UST) financial responsibility requirements with supporting information.  See also the Quick Guide.

• AST financial assurance amounts are based on “an owner or operator’s largest facility, with regards to total AST tank capacity.”
  • An owner or operator (in this discussion, "owner") has two facilities (and only ASTs).  Facility 1 has two 4,000 gallon tanks (total facility capacity of 8,000 gallons), and Facility 2 has three 9,000 gallon tanks (total facility capacity of 27,000 gallons). Facility 2 with the larger total facility capacity will determine the owner’s coverage requirements  ($1 million/$1 million).
  • AST tanks that are not regulated solely due to their small size, at a facility with at least one regulated AST, will have their capacity added to that of the regulated tank(s).  For example, an AST facility with one 9,000 gallon capacity tank and ten 500 gallon capacity tanks will have a total facility AST capacity of 14,000 gallons (requiring $1 million/$1 million coverage). 
  • Any facility with both ASTs and USTs will ignore all aspects of the USTs in determining the AST coverage requirements (then see below). (A facility with regulated USTs and only ‘undersized’ ASTs will, for our calculations, have an AST facility capacity of 0 gallons.)
• UST financial assurance Annual Aggregate Coverage is based on the number of regulated UST tanks covered by the financial mechanism, regardless of location (state) or number of facilities.  (UST Per Occurrence Coverage is based on other parameters.)
  • USTs that are not regulated are not counted.
  • For counting purposes, a “tank” means a single containment unit and does not mean combinations of single containment units
  • Any facility or owner with both USTs and ASTs will ignore all aspects of the ASTs in determining the UST coverage requirements.  (No AST tank is counted, nor is its throughput considered.)
• ASTs and USTs: To determine the financial assurance amounts for an owner who owns both ASTs and USTs, use the larger Per Occurrence Coverage amount as determined separately for ASTs and USTs.  Similarly, use the larger Annual Aggregate Coverage amount as determined by the two parts of the chart. 
• Multiple mechanisms: An owner or operator who uses multiple mechanisms to cover their liability (e.g., self-insurance for out-of-service tanks and insurance for in-service tanks), the calculations for coverage will be determined by the tanks covered by that mechanism.

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