(a) Ambient Concentration Standard.

(1) Except as provided in subsection (d) of this section, no person shall cause or permit emissions from any facility that result in predicted ambient hydrogen sulfide concentrations at any place beyond the facility's perimeter property boundary greater than eighty parts per billion (80 PPB) for any eight-hour averaging period for residential areas, or greater than one hundred parts per billion (100 PPB) for any eight-hour averaging period for nonresidential areas.

(2) No person shall cause or permit emissions from any facility that result in actual ambient hydrogen sulfide concentrations at any place beyond the facility's perimeter property boundary greater than twenty parts per million (20 ppm) for any five-minute averaging period.

(b) Method of Prediction. All estimates of ambient concentrations required under this section shall be performed by the Arkansas Department of Environmental Quality or performed by the facility and approved by the department based on the facility's potential to emit hydrogen sulfide, the applicable air quality models, databases, and other requirements specified in the "Guideline on Air Quality Models (Revised)" (1986), supplement A (1987) and supplement B (1993).

(c) Compliance Plan.

(1) In the event the standard is predicted to be exceeded, the facility or facilities whose emissions are found to contribute to the excess shall be given a reasonable period of time to undertake measures to demonstrate compliance, such as a site-specific risk assessment that demonstrates that the emissions do not pose a risk to human health at the nearest public receptor, ambient monitoring, that demonstrates that the standard is not being exceeded, or undertaking emission reduction measures to reduce emissions of hydrogen sulfide such that the standard will not be exceeded.

(2) The compliance measures and schedule of compliance shall be stated in an enforceable settlement agreement or permit modification or, if the facility does not have an existing permit, an enforcement order.

(d) Control Technology Requirements.

(1) General Requirements. Rather than demonstrate compliance with the ambient limit contained in subsection (a) of this section, a facility may elect to install and operate or continue to operate appropriate control technology that addresses hydrogen sulfide emissions for that source or source category.

(2) Determination of Appropriate Control Technology.

(A) For purposes of this section, "appropriate hydrogen sulfide control technology" means control technology, operational practices, or some combination thereof, which will result in the lowest emissions of hydrogen sulfide that a particular facility is reasonably capable of meeting, considering technological and economic feasibility.

(B) Compliance with all applicable portions of the following technology standards, in accordance with the schedule set forth in such standards, shall be deemed to be compliance with appropriate hydrogen sulfide control technology:

(i) Maximum Achievable Control Technology Standards issued pursuant to section 112 of the Clean Air Act, promulgated at 40 C.F.R. Part 63, when compliance with such standards will reduce hydrogen sulfide emissions;

(ii) Standards of Performance for New Stationary Sources, promulgated at 40 C.F.R. Part 60:

(a) Subpart J, Standards of Performance for Petroleum Refineries;

(b) Subpart BB, Standards of Performance for Kraft Paper Mills;

(c) Subpart VV, Standards of Performance for Equipment Leaks of VOC in the Synthetic Organic Chemicals Manufacturing Industry;

(d) Subpart GGG, Standards of Performance for Equipment Leaks of VOC in Petroleum Refineries;

(e) Subpart KKK, Standards of Performance for Equipment Leaks of VOC from Onshore Natural Gas Processing Plants; or

(f) Subpart LLL, Standards of Performance for Onshore Natural Gas Processing; or

(iii) National Emission Standards for Hazardous Air Pollutants under Title III of the Clean Air Act and standards of performance promulgated pursuant to section 111(d) of the Clean Air Act, when compliance with such standards will reduce hydrogen sulfide emissions.

(C) A facility that is not subject to one (1) of the technology limits listed in subdivision (d)(2)(B) of this section and that wishes to apply appropriate hydrogen sulfide control technology may apply to the department for a determination of appropriateness at any time, but no later than ninety (90) days after a determination that the ambient standard has been exceeded. The application shall be made on such forms and contain such information as the department may require and shall include a reasonable time schedule for implementation. When making a determination of appropriateness, the department shall follow the procedures used for making permitting decisions, including public participation requirements.

(D) The ambient standard shall not apply to the following facilities:

(i) Natural gas pipelines and related facilities that do not transmit gas with a concentration of hydrogen sulfide in excess of four parts per million (4 ppm);

(ii) Natural gas gathering and production pipelines and related facilities that do not transmit gas with a concentration of hydrogen sulfide in excess of thirty parts per million (30 ppm);

(iii) Brine pipelines that carry natural gas as a byproduct of the brine;

(iv) Wastewater treatment facilities; and

(v) Oil and gas drilling and production operations and facilities from the wellhead to the custodial transfer meter as that term is defined by law.

(e) The Oil and Gas Commission is hereby delegated the authority to set hydrogen sulfide standards for oil and gas drilling and production facilities from the wellhead to the custodial transfer meter.