(a) Notwithstanding any other provision of law, unless the person was granted an exemption pursuant to subdivision (b) on or before December 31, 1987, pursuant to Section 25208.4, as it read on December 31, 1988, or pursuant to Section 25208.13 or 25208.18, a person shall not discharge liquid hazardous wastes or hazardous wastes containing free liquids into a surface impoundment, if the surface impoundment, or the land immediately beneath it, contains hazardous wastes and is within one-half mile upgradient from a potential source of drinking water.

A person who owns a surface impoundment which meets the conditions specified in this subdivision shall close the impoundment.

(b) A person may apply to a regional board to exempt a surface impoundment from subdivision (a) pursuant to this subdivision. A person shall submit the application for exemption to the regional board on or before January 1, 1986.

1. (1) A regional board shall either grant or deny an exemption from subdivision (a) on or before December 31, 1987. A regional board may grant an exemption from subdivision (a) only if the regional board makes both of the following findings:

   1. (A) No extremely hazardous wastes are currently being discharged into the surface impoundment, and either one of the following applies:

      1. (i) The records of the person applying for an exemption indicate that no extremely hazardous wastes have been discharged into the surface impoundment.
      2. (ii) Extremely hazardous wastes are not present in the surface impoundment, in the vadose zone, or in the waters of the state.
   2. (B) The surface impoundment is in compliance with Section 25208.5, and a report has been filed pursuant to Section 25208.8.

2. (2) An exemption granted pursuant to this subdivision shall not be effective for more than five years. Applications for an exemption or a renewal of an exemption shall be accompanied by the fee specified in the fee schedule adopted by the state board pursuant to Section 25208.3. A regional board shall not renew the exemption unless the regional board makes both of the following findings:

   1. (A) No hazardous waste constituents have migrated from the surface impoundment into the vadose zone or the waters of the state in concentrations which pollute the vadose zone, or pollute, or threaten to pollute, the waters of the state.
   2. (B) Continuing the operation of the surface impoundment does not pose a significant potential of hazardous waste constituents migrating from the surface impoundment into the vadose zone or the waters of the state, thus polluting the vadose zone, or polluting, or threatening to pollute, these waters.
3. (3) Except as provided in paragraph (4), the regional board shall revoke an exemption granted pursuant to this subdivision and require the person granted the exemption to comply with subdivision (a) if the regional board determines that the surface impoundment granted the exemption is polluting, or threatening to pollute, the waters of the state or that hazardous waste constituents are migrating from the surface impoundment into the vadose zone or the waters of the state in concentrations which pollute or threaten to pollute these waters. The regional board shall also issue a cease and desist order pursuant to Section 13301 of the Water Code and require appropriate removal and remedial actions by the person granted the exemption, or the responsible parties, to clean up any pollution which may have occurred.

4. (4) Notwithstanding paragraph (3), a regional board may continue in effect an exemption granted pursuant to this subdivision if the regional board orders the person to double line the surface impoundment, equip the surface impoundment with a leachate collection system, and conduct groundwater monitoring, as specified in subdivision (a) of Section 25208.5, within one year after granting this continuance, and if the regional board makes all of the following findings:

   1. (A) The surface impoundment granted the exemption has hazardous waste constituents, in concentrations which threaten to pollute the waters of the state, which are migrating from the surface impoundment into the vadose zone, but no hazardous waste constituents have migrated into the waters of the state.
   2. (B) Installing double liners and a leachate collection system and conducting groundwater monitoring, as specified in subdivision (a) of Section 25208.5, will abate the threat to the waters of the state before any hazardous waste constituents migrate to the waters.
   3. (C) All removal and remedial actions necessary to abate the threat specified in subparagraph (A) can be completed prior to the migration of any hazardous waste constituents into the waters of the state.

5. (5) Notwithstanding paragraph (4), the regional board shall revoke the exemption continued pursuant to paragraph (4) and shall require the person granted this continuance to comply with subdivision (a) if the regional board determines either of the following:

   1. (A) The surface impoundment is polluting the waters of the state or that hazardous waste constituents are migrating from the surface impoundment into the vadose zone or the waters of the state in concentrations which pollute, or threaten to pollute, these waters.

   2. (B) The person does not comply with the board’s order or conduct the necessary removal or remedial actions, as required by paragraph (4).

      The regional board shall also issue a cease and desist order pursuant to Section 13301 of the Water Code and require appropriate removal and remedial actions by the person granted the exemption, or the responsible parties, to clean up any pollution which may have occurred, upon making either of these determinations.