#### § 550.303 Facilities described in a new or revised Exploration Plan, Development and Production Plan, or Development Operations Coordination Document.

(a) *New plans.* All Exploration Plans, Development and Production Plans, and Development Operations Coordination Documents shall include the information required to make the necessary findings under [paragraphs (d)](/on/2024-09-16/title-30/section-550.303#p-550.303(d)) through [(i)](/on/2024-09-16/title-30/section-550.303#p-550.303(i)) of this section, and the lessee shall comply with the requirements of this section as necessary.

(b) *Applicability of [§ 550.303](/on/2024-09-16/title-30/section-550.303) to existing facilities.*

(1) The Regional Supervisor may review any Exploration Plan, Development and Production Plan, or Development Operations Coordination Document to determine whether any facility described in the plan should be subject to review under this section and has the potential to significantly affect the air quality of an onshore area. To make these decisions, the Regional Supervisor shall consider the distance of the facility from shore, the size of the facility, the number of sources planned for the facility and their operational status, and the air quality status of the onshore area.

(2) For a facility identified by the Regional Supervisor in [paragraph (b)(1)](/on/2024-09-16/title-30/section-550.303#p-550.303(b)(1)) of this section, the Regional Supervisor shall require the lessee to refer to the information required in [§ 550.218](/on/2024-09-16/title-30/section-550.218) or [§ 550.249 of this part](/on/2024-09-16/title-30/part-550/section-550.249) and to submit only that information required to make the necessary findings under [paragraphs (d)](/on/2024-09-16/title-30/section-550.303#p-550.303(d)) through [(i)](/on/2024-09-16/title-30/section-550.303#p-550.303(i)) of this section. The lessee shall submit this information within 120 days of the Regional Supervisor's determination or within a longer period of time at the discretion of the Regional Supervisor. The lessee shall comply with the requirements of this section as necessary.

(c) *Revised facilities.* All revised Exploration Plans, Development and Production Plans, and Development Operations Coordination Documents shall include the information required to make the necessary findings under [paragraphs (d)](/on/2024-09-16/title-30/section-550.303#p-550.303(d)) through [(i)](/on/2024-09-16/title-30/section-550.303#p-550.303(i)) of this section. The lessee shall comply with the requirements of this section as necessary.

(d) *Exemption formulas.* To determine whether a facility described in an initial, modified, supplemental, or revised Exploration Plan, Development and Production Plan, or Development Operations Coordination Document is exempt from further air quality review, the lessee must use the highest annual-total amount of emissions from the facility calculated for each criteria air pollutant, VOC, and TSP listed in [§ 550.249(a)](/on/2024-09-16/title-30/section-550.249#p-550.249(a)) or [§ 550.218(a)](/on/2024-09-16/title-30/section-550.218#p-550.218(a)) and compare these emissions to the emission exemption threshold (EET) calculated using the following formulas: EET = 3400\*D2/3 for carbon monoxide (CO); and EET = 33.3\*D for total suspended particulates (TSP), sulfur dioxide (SO2), nitrogen oxides (NOX), utilizing NO2 as the indicator pollutant for NOX, and VOC (where EET is the emission exemption threshold expressed in short tons per year, and D is the distance of the proposed facility from the closest onshore area of a State expressed in statute miles). If the amount of these projected emissions is less than or equal to the emission exemption threshold (EET) for the corresponding criteria air pollutant, VOC, and TSP, the facility is exempt from further air quality review required under [paragraphs (e)](/on/2024-09-16/title-30/section-550.303#p-550.303(e)) through [(i)](/on/2024-09-16/title-30/section-550.303#p-550.303(i)) of this section.

(e) *Significance levels (SLs).*

(1) For a facility not exempt under [paragraph (d)](/on/2024-09-16/title-30/section-550.303#p-550.303(d)) of this section, the lessee must use a BOEM approved air quality model to determine whether projected emissions from the facility result in an onshore ambient air concentration above any SL set forth in the following table:

Table 1 to Paragraph (e)(1)—Significance Levels (SLs)

| | Averaging time | | | | |
| --- | --- | --- | --- | --- | --- |
| 1 hour (mg/m3) | 3 hour (μg/m3) | 8 hour (mg/m3) | 24 hour (μg/m3) | Annual (μg/m3) |
| Criteria Air Pollutant: | | | | | |
| Sulfur Dioxide | | 25.0 | | 5.0 | 1.0 |
| PM10 | | | | 5.0 | 1.0 |
| PM2.5 | | | | 1.2 | 0.3 |
| Nitrogen Dioxide1 | | | | | 1.0 |
| Carbon Monoxide | 2.0 | | 0.5 | | |
| | | | | | |
| --- | --- | --- | --- | --- | --- |
| 1 NO2 is the indicator pollutant for NOX. | | | | | |

(2) In the event that the emissions of TSP exceed the EET for TSP, the lessee must use a BOEM approved air quality model to determine whether the projected emissions from the facility result in an onshore ambient air concentration above the SL for either PM10 or PM2.5.

(f) *Significance determinations.*

(1) The projected emissions of any criteria air pollutant from any facility that result in an onshore ambient air concentration above a SL determined under [paragraph (e)](/on/2024-09-16/title-30/section-550.303#p-550.303(e)) of this section for that criteria air pollutant will be deemed to significantly affect the air quality of the onshore area for that criteria air pollutant.

(2) The projected emissions of VOC from any facility which is not exempt under [paragraph (d)](/on/2024-09-16/title-30/section-550.303#p-550.303(d)) of this section will be deemed to significantly affect the air quality of the onshore area for VOC.

(g) *Controls required.*

(1) The projected emissions of any criteria air pollutant from any facility, except a temporary facility, which significantly affect the quality of a nonattainment area, shall be fully reduced. This shall be done through the application of BACT and, if additional reductions are necessary, through the application of additional emission controls or through the acquisition of offshore or onshore offsets.

(2) The projected emissions of any criteria air pollutant from any facility which significantly affect the air quality of an attainment or unclassifiable area shall be reduced through the application of BACT.

(i)

(A) Except for temporary facilities, the lessee also shall use an approved air quality model to determine whether the emissions of TSP or SO2 that remain after the application of BACT cause the following maximum allowable increases over the baseline concentrations established in [40 CFR 52.21](/on/2024-09-16/title-40/section-52.21) to be exceeded in the attainment or unclassifiable area:

Maximum Allowable Concentration Increases

[μg/m3]

| Air pollutant | Averaging times | | |
| --- | --- | --- | --- |
| Annual mean1 | 24-hour maximum | 3-hour maximum |
| Class I: | | | |
| TSP | 5 | 10 | |
| SO2 | 2 | 5 | 25 |
| Class II: | | | |
| TSP | 19 | 37 | |
| SO2 | 20 | 91 | 512 |
| Class III: | | | |
| TSP | 37 | 75 | |
| SO2 | 40 | 182 | 700 |
| | | | |
| --- | --- | --- | --- |
| 1 For TSP—geometric; For SO2—arithmetric. | | | |

(B) No concentration of an criteria air pollutant shall exceed the concentration permitted under the national secondary ambient air quality standard or the concentration permitted under the national primary air quality standard, whichever concentration is lowest for the criteria air pollutant for the period of exposure. For any period other than the annual period, the applicable maximum allowable increase may be exceeded during one such period per year at any one onshore location.

(ii) If the maximum allowable increases are exceeded, the lessee shall apply whatever additional emission controls are necessary to reduce or offset the remaining emissions of TSP or SO2 so that concentrations in the onshore ambient air of an attainment or unclassifiable area do not exceed the maximum allowable increases.

(3)

(i) The projected emissions of VOC from any facility, except a temporary facility, which significantly affect the onshore air quality of a nonattainment area shall be fully reduced. This shall be done through the application of BACT and, if additional reductions are necessary, through the application of additional emission controls or through the acquisition of offshore or onshore offsets.

(ii) The projected emissions of VOC from any facility which significantly affect the onshore air quality of an attainment area shall be reduced through the application of BACT.

(4)

(i) If projected emissions from a facility significantly affect the onshore air quality of both a nonattainment and an attainment or unclassifiable area, the regulatory requirements applicable to projected emissions significantly affecting a nonattainment area shall apply.

(ii) If projected emissions from a facility significantly affect the onshore air quality of more than one class of attainment area, the lessee must reduce projected emissions to meet the maximum allowable increases specified for each class in [paragraph (g)(2)(i)](/on/2024-09-16/title-30/section-550.303#p-550.303(g)(2)(i)) of this section.

(h) *Controls required on temporary facilities.* The lessee must apply BACT to reduce projected emissions of any criteria air pollutant or VOC from a temporary facility that significantly affect the air quality of an onshore area of a State.

(i) *Emission offsets.* When emission offsets are to be obtained, the lessee must demonstrate that the offsets are equivalent in nature and quantity to the projected emissions that must be reduced after the application of BACT; a binding commitment exists between the lessee and the owner or owners of the source or sources; the appropriate air quality control jurisdiction has been notified of the need to revise the State Implementation Plan to include the information regarding the offsets; and the required offsets come from sources which affect the air quality of the area significantly affected by the lessee's offshore operations.

(j) *Review of facilities with emissions below the emission exemption thresholds.* If, during the review of a new, modified, or revised Exploration Plan, Development and Production Plan, or Development Operations Coordination Document, the Regional Supervisor determines or an affected State submits information to the Regional Supervisor which demonstrates, in the judgment of the Regional Supervisor, that projected emissions from an otherwise exempt facility will, either individually or in combination with other facilities in the area, significantly affect the air quality of an onshore area, then the Regional Supervisor shall require the lessee to submit additional information to determine whether emission control measures are necessary. The lessee shall be given the opportunity to present information to the Regional Supervisor which demonstrates that the exempt facility is not significantly affecting the air quality of an onshore area of the State.

(k) *Emission monitoring requirements.* The lessee shall monitor, in a manner approved or prescribed by the Regional Supervisor, emissions from the facility. The lessee shall submit this information monthly in a manner and form approved or prescribed by the Regional Supervisor.

(l) *Collection of meteorological data.* The Regional Supervisor may require the lessee to collect, for a period of time and in a manner approved or prescribed by the Regional Supervisor, and submit meteorological data from a facility.

[[76 FR 64623](https://www.federalregister.gov/citation/76-FR-64623), Oct. 18, 2011, as amended at [85 FR 34937](https://www.federalregister.gov/citation/85-FR-34937), June 5, 2020]