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General Conformity Rule


General Description

Under the General Conformity Rule, federal agencies must work with State, Tribal and local governments in a air quality nonattainment or maintenance areas to ensure that federal actions conform to the initiatives established in the applicable state implementation plan (SIP) or tribal implementation plan.

Summary of Federal Requirements

Conformity determinations are required when a department, agency or instrumentality of the Federal Government engages in, supports in any way or provides financial assistance for, license or permit, or approve any activity which does not conform to an applicable implementation plan (i.e., the State Implementation Plan [SIP]). EPA guidance should be consulted as well as the regulations pertaining to General Conformity.

Conformity Determination Process

A Federal agency making a conformity determination under must provide to the appropriate EPA Regional Office(s), State and local air quality agencies and, where applicable, affected Federal land managers, the agency designated under section 174 of the Act and the MPO a 30 day notice which describes the proposed action and the Federal agency's draft conformity determination on the action.

The Federal agency must notify the appropriate EPA Regional Office(s), State and local air quality agencies and, where applicable, affected Federal land managers, the agency designated under section 174 of the CAA and the MPO within 30 days after making a final conformity determination.

A Federal agency must make public its draft conformity determination by placing a notice by prominent advertisement in a daily newspaper of general circulation in the area affected by the action and by providing 30 days for written public comment prior to taking any formal action on the draft determination. This comment period may be concurrent with any other public involvement, such as occurs in the NEPA process.

Upon request by any person regarding a specific Federal action, a Federal agency must make available for review its draft conformity determination with supporting materials which describe the analytical methods and conclusions relied upon in making the applicability analysis and draft conformity determination.

A Federal agency must document its response to all the comments received on its draft conformity determination and makes the comments and responses available, upon request by any person regarding a specific Federal action, within 30 days of the final conformity determination.

A Federal agency must make public its final conformity determination for a Federal action by placing a notice by prominent advertisement in a daily newspaper of general circulation in the area affected by the action within 30 days of the final conformity determination.

Conformity Determination Requirements

When undertaking a Federal actions not related to activities developed, funded, or approved under the Federal Transit Act, a conformity determination is required for each criteria pollutant or precursor where the total of direct and indirect emissions of the criteria pollutant or precursor in a nonattainment or maintenance area caused by a Federal action would equal or exceed any of the following rates:

  • rates in nonattainment area (NAA):

    • ozone (VOCs or NOX), serious NAA's: 50 tons/yr
    • ozone (VOCs or NOX), severe NAA's: 25 tons/yr
    • ozone (VOCs or NOX), extreme NAA's: 10 tons/yr
    • other ozone NAA's outside an ozone transport region: 50 tons/yr
    • other ozone NAA's inside an ozone transport region, VOC: 50 tons/yr
    • other ozone NAA's inside an ozone transport region, NOX: 100 tons/yr
    • carbon monoxide, all NAA's: 100 tons/yr
    • SO2 or NO2, All NAA's: 100 tons/yr
    • PM-10, moderate NAA's: 100 tons/yr
    • PM-10, serious NAA's: 70 tons/year
    • PM 2.5, direct emissions: 100 tons/yr
    • PM 2.5, SO2: 100 tons/yr
    • PM 2.5, NOX (unless determined not to be a significant precursor): 100 tons/yr
    • PM 2.5, VOC or ammonia (if determined to be significant precursor): 100 tons/yr
    • Pb, all NAA's: 25 tons/yr.
  • rates in maintenance areas:
    • ozone (NOX, SO2, or NO2), all maintenance areas: 100 tons/yr
    • ozone (VOCs), maintenance area inside an ozone transport region: 50 tons/yr
    • ozone (VOCs) maintenance area outside an ozone transport region: 100 tons/yr
    • carbon monoxide, all maintenance areas: 100 tons/yr
    • PM-10, all maintenance areas: 100 tons/yr
    • PM 2.5, direct emissions: 100 tons/yr
    • PM 2.5, SO2: 100 tons/yr
    • PM 2.5, NOX (unless determiend not to be a significant precursor): 100 tons/yr
    • - PM.2.5, VOC or ammonia (if determiens to be significant precursors): 100 tons/yr
    • - Pb, all maintenance areas: 25 tons/yr.

A determination that an action is in conformance with the applicable implementation plan does not exempt the action from any other requirements of the applicable implementation plan, NEPA, or the CAA.

Conformity Status

The conformity status of a Federal action automatically lapses 5 years from the date a final conformity determination is reported, unless the Federal action has been completed or a continuous program has been commenced to implement that Federal action within a reasonable time.  Ongoing Federal activities at a given site showing continuous progress are not new actions and do not require periodic redeterminations so long as such activities are within the scope of the final conformity determination.  If, after the conformity determination is made, the Federal action is changed so that there is an increase in the total of direct and indirect emissions, above the regulatory minimum levels, a new conformity determination is required.

Exemptions from Conformity Determination

The requirement for conformity determination does not apply to the following Federal actions:

  • actions where the total of direct and indirect emissions are below the specified emissions levels
  • actions which would result in no emissions increase or an increase in emissions that is clearly de minimis
  • actions where the emissions are not reasonably foreseeable, such as the following:
    • initial Outer Continental Shelf lease sales which are made on a broad scale and are followed by exploration and development plans on a project level
    • electric power marketing activities that involve the acquisition, sale and transmission of electric energy
  • actions which implement a decision to conduct or carry out a conforming program such as prescribed burning actions which are consistent with a conforming land management plan.

A conformity determination is not required for the following Federal actions (or portion thereof):

  • the portion of an action that includes major new or modified stationary sources that require a permit under the new source review (NSR) program or the prevention of significant deterioration (PSD) program
  • actions in response to emergencies or natural disasters such as hurricanes, earthquakes, etc., which are commenced on the order of hours or days after the emergency or disaster and, if applicable, which meet the requirements for Federal actions which are part of a continuing response
  • research, investigations, studies, demonstrations, or training (unless otherwise exmpted) where no environmental detriment is incurred and/or, the particular action furthers air quality research, as determined by the State agency primarily responsible for the applicable SIP
  • alteration and additions of existing structures as specifically required by new or existing applicable environmental legislation or environmental regulations (e.g., hush houses for aircraft engines and scrubbers for air emissions)
  • direct emissions from remedial and removal actions carried out under CERCLA (and associated regulations to the extent such emissions either comply with the substantive requirements of the PSD/NSR permitting program or are exempted from other environmental regulation under the provisions of CERCLA and applicable regulations issued under CERCLA.)

Presumption of Conformity

Federal agencies meet the following criteria for establishing activities that are presumed to conform by fulfilling one of the following requirements:

  • clearly demonstrate, using appropriate methods, that the total of direct and indirect emissions from the type of activities which would be presumed to conform would not:

  • cause or contribute to any new violation of any standard in any area
  • interfere with provisions in the applicable SIP for maintenance of any standard
  • increase the frequency or severity of any existing violation of any standard in any area
  • delay timely attainment of any standard or any required interim emission reductions or other milestones in any area including, where applicable, emission levels specified in the applicable SIP for purposes of one of the following:
    • a demonstration of reasonable further progress
    • a demonstration of attainment
    • a maintenance plan
  • the Federal agency provides documentation that the total of direct and indirect emissions from such future actions would be below the emission rates for a conformity determination, based, for example, on similar actions taken over recent years.

Additionally, the following procedures must be followed to presume that activities will conform:

  • the Federal agency identifies through publication in the Federal Register its list of proposed activities that are presumed to conform and the basis for the presumptions
  • the Federal agency notifies the appropriate EPA Regional Office(s), State and local air quality agencies and, where applicable, the agency designated under section 174 of the Act and the MPO and provides at least 30 days for the public to comment on the list of proposed activities presumed to conform
  • the Federal agency documents its response to all the comments received and makes the comments, response, and final list of activities available to the public upon request
  • the Federal agency publishes the final list of activities in the Federal Register.

Where an action otherwise presumed to conform is a regionally significant action or does not meet the criteria for establishing activities that are presumed to conform, that action shall not be presumed to conform.

Transportation

Conformity determinations for Federal actions related to transportation plans, programs, and projects developed, funded, or approved under title 23 U.S.C. or the Federal Transit Act (49 U.S.C. 1601 et seq.) are not required to meet the conformity determination requirements under the Clean Air Act. Instead they must meet the procedures and criteria of 40 CFR 51, subpart T.

Summary of State Requirements

The Federal conformity rules under 40 CFR 93, Subpart B, in addition to any existing applicable State requirements, establish the conformity criteria and procedures necessary to meet the Clean Air Act requirements until such time as the required conformity SIP revision is approved by EPA.

The following states have had their conformity rules approved by EPA: Alabama, Alaska, Arizona, California*, Colorado, District of Columbia, Delaware, Illinois, Iowa, Indiana, Kansas, Kentucky, Louisiana, Maine, Maryland, Michigan, Minnesota, Missouri, Montana, Nebraska, New Hampshire, New Mexico, Ohio, Oregon, South Carolina, Texas, Virginia, West Virginia, and Wyoming.

Additionally, EPA has accepted the SIP plans for these areas in California: South Coast AQMD, Santa Barbara County APCD, San Joaquin Unified APCD, Yolo-Solano AQMD, Ventura County APCD, San Diego APCD, Sacramento APCD, Placer County APCD, Monterey Bay Unified APCD, Mojave AQMD, Feather River AQMD, Imperial County APCD, Great Basin Unified APCD, El Dorado County APCD, Butte County APCD, and Bay Area AQMD.

Laws and Statutes

Clean Air Act

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