40 CFR § 280.115 - Replenishment of guarantees, letters of credit, or surety bonds.
(a) If at any time after a standby trust is funded upon the instruction of the Director of the implementing agency with funds drawn from a guarantee, local government guarantee with standby trust, letter of credit, or surety bond, and the amount in the standby trust is reduced below the full amount of coverage required, the owner or operator shall by the anniversary date of the financial mechanism from which the funds were drawn:
(1) Replenish the value of financial assurance to equal the full amount of coverage required; or
(2) Acquire another financial assurance mechanism for the amount by which funds in the standby trust have been reduced.
(b) For purposes of this section, the full amount of coverage required is the amount of coverage to be provided by § 280.93. If a combination of mechanisms was used to provide the assurance funds which were drawn upon, replenishment shall occur by the earliest anniversary date among the mechanisms.