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  • Allison Stalker

EPA Issues Final Amendments to RICE Rules

Updated: Aug 29, 2023

The Environmental Protection Agency (EPA) announced today that the final amendments have been issued to the National Emission Standards for Hazardous Air Pollutants for Reciprocating Internal Combustion Engines (RICE). These standards were created to reduce air pollution from stationary engines at industrial, agricultural, oil and gas production, power generation and other facilities. The EPA states that these final amendments “will ensure that the standards are cost effective, achievable and protective”.


The EPA estimates that the new changes will reduce the capital and annual costs of the original 2010 rules by $287 million and $139 million respectively. Additionally, the rules are estimated to reduce 2,800 tons per year (tpy) of hazardous air pollutants (HAP); 36,000 tpy of carbon monoxide; 2,800 tpy of particulate matter; 9,600 tpy of nitrogen oxides; and 36,000 tpy of volatile organic compounds.


According to the EPA, these rules generally apply to the following:

  • engines typically used in sparsely populated areas for oil and gas production

  • engines in remote areas of Alaska

  • engines scheduled to be replaced in the next few years due to state or local requirements, and certain engines installed in 2006

  • engine testing requirements for formaldehyde emissions

  • engines for offshore vessels operating on the Outer Continental Shelf

  • engines used in emergency demand response programs

The amendments include changes to various parts of the RICE rules. For example, these are the new amendments for area source stationary spark ignition engines above 500 HP:

  • These engines are typically natural gas powered engines that are used to power equipment for oil and gas production.

  • EPA is replacing numerical emission limits for existing area source stationary spark ignition (SI) 4-stroke engines above 500 horsepower (HP) that are located in populated areas with requirements to install catalytic controls, conduct an initial test and annual performance checks of the catalyst, and equip the engine with a high temperature shutdown device or monitor the catalyst inlet temperature continuously.

    • Populated areas are defined as not being on Department of Transportation (DOT) Class 1 pipeline segments or having more than 5 buildings within 0.25 mile radius of the engine.

  • EPA is specifying that existing area source stationary SI 4-stroke engines above 500 HP that are not located in populated areas are subject to management practices.

    • Unpopulated areas are DOT Class 1 pipeline segments or having 5 or fewer buildings within 0.25 mile radius of the engine.

There are also a number of changes to the regulation for engines scheduled to be replaced in the next few years, stationary compression ignited (CI) engines on offshore vessels, emergency engines, and engines in remote areas of Alaska. To find an overview on these amendments, the EPA has created a fact sheet found here. The actual rule can be found here. More specific information on how the rule affects emergency engines can be found here.

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