a) The operator may utilize either of the following mechanisms to comply with Section 830.604:

1. 1) A cash reserve fund; or
2. 2) Self-insurance.

b) An operator choosing to use a cash reserve account as the mechanism by which to comply with Section 830.604 shall:

1. 1) Fully fund the account within one year after the initial receipt of waste, except that facilities in operation on the November 10, 1994 shall fully fund the account by November 10, 1995; and
2. 2) Thereafter maintain full funding pending the expenditure of such funds to cover the costs of closure.

c) An operator choosing to use self-insurance as the mechanism by which to comply with subsection (a) of this Section shall have:

1. 1) Net working capital and tangible net worth each at least six times the current cost estimate;
2. 2) Tangible net worth of at least $10 million;
3. 3) Assets in the United States amounting to at least 90 percent of the operator's total assets and at least six times the current cost estimate; and

4. 4) Either:

   1. A) Two of the following three ratios: a ratio of total liabilities to net worth of less than 2.0; a ratio of the sum of net income plus depreciation, depletion and amortization to total liabilities of greater than 0.1; or a ratio of current assets to current liabilities of greater than 1.5; or
   2. B) A current rating of AAA, AA, A or BBB for its most recent bond issuance, as issued by Standard and Poor, or a rating of Aaa, Aa, A or Bbb, as issued by Moody.