Section 49.4172 - Emissions inventory(a)Applicability. The emissions inventory requirements of this section apply to each oil and natural gas source, as identified in § 49.4169(b) , that has actual emissions of any pollutant identified in paragraph (c) of this section greater than or equal to one ton in any consecutive 12-month period.(b) Each oil and natural gas source must submit an inventory for every third year, beginning with the 2023 calendar year, for all emission units at a source.(c) The inventory must include the total emissions for PM10, PM2.5, oxides of sulfur, nitrogen oxides, carbon monoxide, and volatile organic compounds, as defined at 40 CFR 51.50 , for each emissions unit at the source. Emissions for each emissions unit at the source must be calculated using the emissions unit's actual operating hours, appropriate emissions rates, the use of performance test results where applicable, product rates and types of materials processed, stored, or combusted during the calendar year of the reporting period.(d) The inventory must include the type and efficiency, for each pollutant controlled, of any air pollution control equipment present at the reporting source. The detail of the emissions inventory must be consistent with the detail and data elements required by 40 CFR part 51, subpart A.(e) The inventory must be submitted to the EPA no later than April 15th of the year following each inventory year.