4 The record articles

U.S. EPA has Finalized NOx Limits to Curb Ozone Transport from non-EGUs in 20 States

Posted: March 22nd, 2023

Authors: Amy M.  Roy R. 

On March 15, 2023, the U.S. Environmental Protection Agency (EPA) signed a final rule titled Federal “Good Neighbor Plan” for the 2015 Ozone National Ambient Air Quality Standards” (NAAQS). This final rule contains first-time requirements to limit emissions of nitrogen oxides (NOX) during ozone season from nine types of non-electric generating units (non-EGUs) in the following 20 states: Arkansas, California, Illinois, Indiana, Kentucky, Louisiana, Maryland, Michigan, Mississippi, Missouri, Nevada, New Jersey, New York, Ohio, Oklahoma, Pennsylvania, Texas, Utah, Virginia, and West Virginia. The final rule does not include requirements for non-EGUs in Minnesota, Wisconsin, or Wyoming, differing from the 2022 proposal.

The rule establishes NOX emissions limitations and associated compliance requirements during the ozone season for the following emissions unit types for sources in non-EGU industries: reciprocating internal combustion engines (RICE) in Pipeline Transportation of Natural Gas sources; kilns in Cement and Cement Product Manufacturing sources; reheat furnaces in Iron and Steel Mills and Ferroalloy Manufacturing sources; furnaces in Glass and Glass Product Manufacturing sources; boilers in Iron and Steel Mills and Ferroalloy Manufacturing, Metal Ore Mining, Basic Chemical Manufacturing, Petroleum and Coal Products Manufacturing, and Pulp, Paper, and Paperboard Mills; and municipal solid waste combustors. The compliance date for non-EGU requirements is May 1, 2026, with an option to request an extension if it is not possible to install the required controls by then.

The rule will apply to all existing emissions units and to any future emissions units constructed in the covered states. The following table shows the final non-EGU emissions limits.

Industry Emissions Unit Type Form of Final Emissions Limits Final Ozone Season NOX Emissions Limits
Pipeline Transportation of Natural Gas RICE > 1,000 brake horsepower (BHP) Grams per horsepower hour (g/hp-hr) Four Stroke Rich Burn: 1.0 g/hp-hr

Four Stroke Lean Burn: 1.5 g/hp-hr

Two Stroke Lean Burn: 3.0 g/hp-hr

Cement and Concrete Product Manufacturing Kilns with potential to emit (PTE) > 100 tpy NOX Pounds per ton (lb/ton) of clinker Long Wet: 4.0 lb/ton

Long Dry: 3.0 lb/ton

Preheater: 3.8 lb/ton

Precalciner: 2.3 lb/ton

Preheater/precalciner: 2.8 lb/ton

Iron and Steel Mills and Ferroalloy Manufacturing Reheat Furnaces with PTE > 100 tpy NOX Pounds per million British Thermal Units (lb/MMBtu) Test and set limit based on installation of low-NOX burners
Glass and Glass Product Manufacturing Furnaces with PTE > 100 tpy NOX Pounds per ton of glass produced (lb/ton) Container Glass Furnace: 4.0 lb/ton

Pressed/Blown Glass Furnace: 4.0 lb/ton

Fiberglass Furnace: 4.0 lb/ton

Flat Glass Furnace: 9.2 lb/ton

Iron and Steel Mills and Ferroalloy Manufacturing; Metal Ore Mining; Basic Chemical Manufacturing; Petroleum and Coal Products Manufacturing; Pulp, Paper, and Paperboard Mills Fossil Fuel-Fired Boilers ≥100 MMBtu/hr Lb/MMBtu (30-day average) Coal: 0.20 lb/MMBtu

Residual Oil: 0.20 lb/MMBtu

Distillate Oil: 0.12 lb/MMBtu

Natural Gas: 0.08 lb/MMBtu


The limits for multifuel boilers are pro-rated based on heat input.

Solid Waste Combustors and Incinerators Combustors or incinerators ≥ 250 tons of waste/day Parts per million, dry volume basis (ppmvd) 110 ppmvd (24-hour average)

105 ppmvd (30-day average)


Several important changes were made to the originally proposed affected sources and emissions limits between the proposed and final rules based on information obtained during the public comment period, as summarized below:

Industry Final Rule Revisions
Pipeline Transportation of Natural Gas
  • Emergency RICE excluded from applicability
  • Provisions for Facility-wide averaging plans added
Cement and Concrete Product Manufacturing
  • Daily NOX cap limit provisions removed
Iron and Steel Mills and Ferroalloy Manufacturing
  • Blast furnaces, basic oxygen furnaces, electric arc furnaces, ladle/tundish preheaters, annealing furnaces, vacuum degassers, ladle metallurgy furnaces, taconite production kilns, and coke ovens (charging, coking, and pushing) removed from applicability
  • Provisions for reheat furnaces > 100 tpy PTE were retained, with requirement for low NOX burners and emissions limits based on  “test and set” concept
Glass and Glass Product Manufacturing
  • Alternative requirements that may apply during startup, shutdown, and idling conditions were added
Iron and Steel Mills and Ferroalloy Manufacturing; Metal Ore Mining; Basic Chemical Manufacturing; Petroleum and Coal Products Manufacturing; Pulp, Paper, and Paperboard Mills
  • A low-use boiler exemption was added
  • Process heaters, biomass boilers, and recovery boilers excluded from applicability


Several additional final rule clarifications regarding the non-EGU provisions of the rule are as follows:

  • U.S. EPA finalized a provision that allows a source to request approval of a case-by-case emissions limit based on a showing that an emissions unit cannot meet the applicable standard due to technical impossibility or extreme economic hardship. The request must be submitted within a year of the effective date of the final rule.
  • U.S. EPA has provided a process for individual non-EGU sources to seek limited compliance extensions extending no later than 2029 based on a case-by-case demonstration of necessity.
  • U.S. EPA will allow sources to rely on enforceable requirements that limit its PTE and is finalizing a regulatory definition of PTE that consistent with the definitions of that term in the Title V and NSR permit programs. However, the applicability criteria for the Cement and Concrete Manufacturing, Iron and Steel and Ferroalloy Manufacturing, and Glass and Glass Product Manufacturing industries only include enforceable PTE limits in effect as of the effective date of the final rule (60 days after it is published in the Federal Register).
  • Cogeneration units are not covered under the EGU requirements but are subject to the rule if they meet the applicability criteria for boilers.
  • Non-EGUs are not included in the EGU trading program.
  • Emissions testing is required no more frequently than once per year and requests for alternate monitoring are allowed.
  • Recordkeeping is required for exempt low-use boilers (<10% per year over three years or <20% per year, hourly basis) and emergency engines. If you exceed the 10% per year hours of operation over three years or the 20% hours of operation per year criteria, you must meet the applicable emissions limits and other applicable provisions as soon as possible but not later than one year after you exceeded the low-use boiler criteria.
  • U.S. EPA did not exempt temporary boilers.
  • The boiler standards apply only to boilers with a design capacity 100 MMBtu/hr or greater burning 90% or more by heat input of coal, oil, gas, or a combination of those fuels. The limit for a combination boiler is prorated based on the amount of coal, oil, gas burned, 30-day average.
  • Submittal of monitoring plans, compliance reports, and emissions test data is required via the Compliance and Emissions Data Reporting Interface (CEDRI).

The final rule has not yet been published in the Federal Register, but once it does, legal action is sure to follow. If you have questions on whether your facility is covered under the final rule or need help planning for compliance, please reach out to Amy Marshall or Roy Rakiewicz.


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