NAC444.667. Operating criteria: Control of explosive gas.

     1. An owner or operator shall provide for the control of explosive gas at the municipal solid waste landfill unit in accordance with the provisions of this section.

     2. The owner or operator shall ensure that:

     (a) The concentration of methane gas generated at the unit does not exceed 25 percent of the lower explosive limit for methane in structures, excluding components for any system to control or recover the gas; and

     (b) The concentration of methane gas does not exceed the lower explosive limit for methane at the boundary of the unit.

     3. The owner or operator shall carry out a routine program for monitoring methane gas to ensure that the standards set forth in subsection 2 are met. Except as otherwise provided in subsection 4, the level of methane must be monitored at least quarterly each year. The type and frequency of monitoring must be determined based on the:

     (a) Conditions of the soil;

     (b) Hydrogeologic conditions surrounding the unit;

     (c) Hydraulic conditions surrounding the unit; and

     (d) Location of the structures and boundaries of the unit.

     4. The solid waste management authority may, after public review and comment, allow the owner or operator of a Class II site to monitor the level of methane gas less frequently than one time each quarter. In deciding whether to allow such a deviation, the solid waste management authority shall consider:

     (a) The unique characteristics of small communities;

     (b) Climatic and hydrogeologic conditions; and

     (c) Whether allowing the deviation would have an adverse effect on human health or the environment.

     5. If the owner or operator detects levels of methane gas exceeding the limits specified in paragraph (a) of subsection 2, he or she shall:

     (a) Immediately take all necessary actions to ensure protection of public health and safety and notify the solid waste management authority;

     (b) Except as otherwise provided in subsection 6, within 7 days after detection, place in the operating records for the unit the levels of methane gas detected and a description of the actions taken to protect public health and safety; and

     (c) Except as otherwise provided in subsection 6, within 60 days after detection, carry out a plan for remediation for the releases of methane gas, place a copy of the plan in the operating records and notify the solid waste management authority that the plan has been carried out. The plan must describe the nature and extent of the problem and the proposed remedy.

     6. The solid waste management authority may establish alternative schedules for demonstrating compliance with paragraphs (b) and (c) of subsection 5.

     7. As used in this section, “lower explosive limit” means the lowest percent by volume of a mixture of explosive gases in air that will propagate a flame at 25°C and at atmospheric pressure.

     (Added to NAC by Environmental Comm’n, eff. 11-8-93; A 3-1-94; R034-98, 4-17-98)