Show All Minnesota State Implementation Plan (SIP)
What is the State Implementation Plan (SIP)?
The goal of the federal Clean Air Act (CAA) is to ensure that human health and the environment are protected from the adverse effects of air pollution. Under the CAA, the U.S. Environmental Protection Agency (EPA) sets limits on certain air pollutants, along with standards for how much of various air pollutants certain sources can emit.
The CAA places most of the responsibility on the states to prevent air pollution and control air pollution at its source. In order for a state to conduct certain air quality programs, the state must adopt a plan and obtain approval of the plan from the EPA. The federal review and approval process provides for some consistency in different state programs and ensures that each state program complies with the requirements of the CAA and EPA rules.
The vehicle for demonstrating compliance with the CAA and EPA rules is the State Implementation Plan or "SIP," which is established as part of Title I, Section 110 of the CAA. A SIP adopted by the state and approved by the EPA is legally binding under both state and federal law, and may be enforced by authorities at either level.
Criteria Air Pollutants and the National Ambient Air Quality Standards
The SIP focuses on regulation of the criteria air pollutants, which are those pollutants for which EPA has set a National Ambient Air Quality Standard (NAAQS) to protect human health. Air toxics, or hazardous air pollutants, are regulated under other portions of the CAA and are not included in the SIP.
The six criteria pollutants are: carbon monoxide (CO), sulfur dioxide (SO2), ozone (O3), nitrogen oxides (NOx), lead, and particulate matter in two size fractions: less than 10 microns (PM10) and less than 2.5 microns (PM2.5). Primary and secondary NAAQS are established for each of these pollutants. Primary standards define the air quality required to prevent adverse impacts on human health while secondary standards define the air quality required to prevent adverse impact on other elements of the environment such as vegetation.
A listing of the current health-based primary NAAQS standards can be found on EPA’s Web site.
The main objective of the SIP process is to ensure that all areas of the country meet the NAAQS. If EPA determines that the ambient air in all or part of state does not meet a NAAQS, the area is designated as a “nonattainment area” and the state must submit a SIP revision that outlines what the state is doing to address the relevant air pollutant. In areas where the ambient air does meet the NAAQS, the state often must demonstrate that it has sufficient authority to control air pollution in order to ensure that the area continues to maintain the NAAQS.
If a state is not in attainment with these standards, it must have a SIP to demonstrate how it will come into attainment. States that are in attainment must demonstrate that they have authority to require measures in order to remain in attainment, and in some cases must provide more substantive demonstrations that the standards will be maintained.
One important aspect of the SIP is that states are required to have a New Source Review (NSR) permitting program, known as Nonattainment New Source Review (NA NSR) in nonattainment areas and Prevention of Significant Deterioration (PSD) in attainment or maintenance areas. These permitting programs apply to new and modifying major sources and are designed to ensure that NAAQS are protected. States can have a SIP-approved NSR program, operated under their own rules but meeting minimum federal requirements, or operate a delegated NSR program by following the federal rules. Minnesota’s SIP includes an approved program for NA NSR and a delegated program for PSD. For more information, see the MPCA’s NSR Web page.
The EPA can also require States to submit SIPs to meet air quality goals other than the NAAQS, such as SIPs that have been required for regional haze.
Other CAA programs also require states to design an implementation plan and submit that plan to EPA for approval. However, these are not considered SIPs. Examples of such plans include the state Title V operating permit program and programs (such as 111(d) plans) to deal with hazardous air pollutants. Since these plans do not specifically relate to criteria pollutants, they are not part of the SIP. However, the Minnesota Pollution Control Agency (MPCA) has submitted, and EPA has approved, part of Minnesota’s operating permit program as a state rule for SIP inclusion.
What is in the SIP and where can I find it?
The contents of a SIP can be considered in two broad categories, (1) site or area-specific plans and documents; and (2) state rules or statutes and programs. Both become federally enforceable once approved by EPA as part of the SIP.
Any site-specific plan or rule that the state or EPA believes is necessary to attain and maintain the NAAQS should be included in the SIP. A state may request, on its own, to include a plan or rule in the SIP, or EPA may require a state to include certain rules and plans in its SIP. For instance, EPA’s recent revisions to the fine particle (PM2.5) and ozone NAAQS will require states with nonattainment areas to write and submit SIPs to attain those standards, and for other areas to demonstrate that their SIPs contain appropriate measures to allow them to maintain the standards.
If a state fails to meet an EPA deadline for SIP submittal, or does not include an EPA mandated item in its SIP, the state may be subject to a Federal Implementation Plan (FIP). Under a FIP, EPA determines what steps are necessary within the state to meet the NAAQS or other requirements.
Once a requirement is put into the SIP to control pollution, it does not expire. Even once the area attains the NAAQS, the requirements must stay in place in order to ensure that the NAAQS are maintained. Requirements may be revised, but are subject to EPA approval. EPA reviews changes carefully to ensure there is no backsliding. Minnesota had several areas designated as nonattainment for lead, PM10, and SO2 during the 1980s and 1990s. Although these areas were all redesignated to attainment by 2002, SIP requirements on various facilities remain in place.
SIPs that were submitted by states to the EPA and acted upon by the EPA are listed in 40 CFR pt. 52. Minnesota’s SIP is identified in 40 CFR § 52, subpart Y. Since the SIP has changed considerably since its original submittal, and the CFR is updated only annually, some of the items listed in 40 CFR § 52, subpart Y are obsolete and recent additions to the SIP may not be reflected. To view, go to the Code of Federal Regulations and retrieve 40 CFR pt. 52, subp. Y.
The document below lists the specific sources and facilities that are subject to limits established by the SIP, listed by geographic area and pollutant. It also includes a listing of the enforceable document that contains those requirements, the state effective date, and the federal approval and effective date. In addition, the document lists Minnesota’s SIP-included state rules. The MPCA’s SIP coordinator can supply current information on the status of the SIP.
What's in Minnesota's SIPThe following links contain more detailed information about SIPs and what is included in Minnesota’s SIP.
SIP Revisions
Revisions to the SIP may be required when there are amendments to the CAA, changes to EPA regulations (such as new NAAQS), or if the state initiates changes to its air program.
When the MPCA submits a SIP to EPA, whether it is a new plan or a revision to an existing plan, the SIP submittal includes:
- A formal letter of submittal to the EPA Regional Administrator from the Commissioner
- Copies of final, enforceable documents (such as administrative orders, permits with SIP conditions, or adopted rules) that contain emission limits and compliance requirements for culpable sources
- Air dispersion modeling of the area showing projected or continued attainment of the NAAQS (if necessary)
- Letters from the Attorney General’s Office or other documentation demonstrating that the state has legal authority to implement the SIP revision and that state procedural requirements were complied with in adopting the SIP
- Copy of the public notice - every change to the SIP, no matter how small, is required to be public noticed for 30 days
- If a public meeting is held, certification that it was held after a 30-day notice (a public meeting is not required but can always be requested during the comment period)
- Any public comments received, along with MPCA’s response
The legal requirements for SIP submittals are found in the CAA, section 110, parts (a) and (d). If a state fails to meet an EPA deadline for SIP submittal, or does not include an EPA mandated item in its SIP, the state may be subject to a Federal Implementation Plan (FIP). Under a FIP, EPA determines what steps are necessary within the state to meet the NAAQS or other requirements.
At this time, many of the MPCA’s SIP submittals are revisions to enforceable documents for specific sources that have already been included in the SIP. These are usually necessitated by changes being made at the source. In such cases, the SIP must demonstrate that the changes being made at the source and to the SIP-approved emission limits will not jeopardize the area’s attainment status. The MPCA may also submit revisions to update the rules that are included in the SIP. For these revisions, dispersion modeling would not be required unless the rule affects emission levels. Also, if the rules submitted are thought to be a “relaxation” of the SIP, the MPCA must justify this and ensure there will be no backsliding.
SIP Revisions in Progress
As described above, existing SIP requirements can be revised. All changes to the SIP require public notice and comment, and are then submitted to EPA for approval.
Public notices for SIP revisions can be found on MPCA’s Public Notice Web page. If the SIP revision is being proposed in conjunction with a proposed permit, links to the proposed permit can also be found on that page.
There are currently no SIP revisions in progress.
Revising the NAAQS and Resulting SIP Revisions
The NAAQS are not static. EPA must review each standard every five years, in order to ensure that each standard continues to provide adequate human health protection. Although the standard reviews do not always result in revisions of the standards, recent and upcoming reviews have and are likely to result in lower standards for several pollutants. From 2008 through 2012, EPA will review and very likely revise the NAAQS for each of the six criteria pollutants, making the standards more stringent. Therefore, it is likely that some areas in Minnesota will become nonattainment areas for some of the criteria pollutants.
The MPCA is currently working on the following criteria pollutants:
- Lead - Nonattainment area in Eagan
- NO2 - New standard implementation
- SO2 -New standard implementation and infrastructure SIP
- Ozone and PM2.5 - Preparing for new standard
Designations for New Standards
When a new or revised NAAQS is promulgated, EPA sets forth guidelines for data to be used to determine whether the standard is being attained. The data to be used can include both monitoring and modeling data. States are responsible for making designation recommendations to EPA, but the final designation of an area’s status as attainment or nonattainment is made by the EPA.
Minnesota’s original nonattainment areas were determined by which air quality control monitors showed a violation of a particular criteria pollutant standard. Then an area surrounding the monitor, including all potentially significant contributors to that violation, was delineated as the nonattainment area. By definition, nonattainment areas must contain the ambient air that exceeds the standard along with all the sources that contribute to the nonattainment.
Generally, the potentially significant contributors to each nonattainment area are identified by determining which sources (both point and area) emit a significant amount of the pollutant of concern. These sources are termed culpable sources. This data is obtained from an emissions inventory of each potential source in the area. Culpable sources can also be determined through the use of air quality modeling, to determine what sources have an impact on the area that is exceeding the standard. Occasionally, other methods such as receptor modeling are used to determine potentially significant contributors. The distance and direction of the potential source from the monitor with the violation is also considered.
As EPA revises the NAAQS, it will provide guidance on designating nonattainment areas. MPCA will follow EPA guidance, but the process will likely be similar to that described above.
Special Requirements for Stationary Sources in Nonattainment Areas
Once an area is officially designated as a nonattainment area by EPA, some specific requirements come into play. The first is nonattainment New Source Review (NA NSR) permitting for new or expanding facilities, including requirements for offsets. Minnesota’s Offset rule or NA NSR program became federally enforceable on May 31, 1994. The rule is found at Minn. R. 7007.4000 - 7007.4030 and essentially incorporates by reference 40 CFR § 51, Appendix S, with some exceptions. This EPA approval means that the MPCA operates a SIP-approved NA NSR program in nonattainment areas.
The Offset rule applies to new major sources or major modifications in nonattainment areas (for the pollutant that the area is designated nonattainment), or new major sources or major modifications that would contribute to a violation of the NAAQS in a nonattainment area. For clarity, if a facility located in a SO2 nonattainment area wanted to do a major modification for PM10, the facility would not be subject to the Offset rule.
New sources wanting to locate in a nonattainment area must go through NA NSR if they have the potential to emit 100 tpy or more of the criteria pollutant for which the area is designated nonattainment. If a facility already located in a nonattainment area wants to do a modification, it must go through the NA NSR process if the change would result in a net emissions increase above the thresholds noted above.
The following conditions must be met by a source before an NSR permit can be granted to a source located in a nonattainment area:
- The source must meet an emission limitation which specifies the lowest achievable emission rate (LAER) for that particular source.
- The source must certify that all other facilities it owns or operates in Minnesota are in compliance with all applicable requirements.
- The source must obtain emission reductions, or “offsets”, from existing sources in the same area of the proposed source or source modification. In addition, offsets are based on actual emissions and can only be intrapollutant (e.g. SO2 for SO2, not PM10 for SO2).
For example, if Company X wants to locate a new major source in a SO2 nonattainment area, it must obtain SO2 emission offsets from another facility in the area. The facility that it obtains the emission offsets from can be owned by Company X or owned by another company. If Company X wants to do a SO2 major modification at Facility Z, it has three options to obtain SO2 offsets: the offsets can come right from Facility Z (internal netting), from another facility in the area owned by Company X, or from a facility in the area owned by any other company.
Note that, at this time, Minnesota does not have a banking provision in its Offset rule, so emission reductions at a facility cannot be saved to provide offsets for a source seeking a permit in the future. - Emission offsetting must provide a positive net air quality benefit in the nonattainment area. This means the emission offset must be greater than a one-to-one ratio. Dispersion modeling may also be needed to determine whether the new source or modification will attain the ambient air quality standards.
Developing SIPs for New Standards
Once an area is designated as a nonattainment area, the state must develop a plan to bring that area back into attainment. Monitoring and modeling data are used to determine the specific sources or source categories that are important contributors to the nonattainment.
The plan must include permanent, non-expiring, enforceable limits and controls on sources that contribute to the nonattainment, accomplished either through rules or site-specific conditions. The plan must then include a demonstration, usually using air quality modeling, that the controls included in the plan will be sufficient to bring the area back into attainment by a date specified by EPA.
Implementing SIP Limits
Originally, MPCA imposed site-specific conditions through issuing an Administrative Order (Order) to each of the culpable sources. These Orders were similar to the MPCA’s early (pre-Title V) air quality permits except that they regulated only one pollutant and did not expire. Currently, the MPCA’s preferred practice is to place federally-enforceable limits in a facility’s Title V or state permit. This ensures that all the applicable requirements for a facility are contained in a single document. Each limit that is established under Minnesota’s Title I SIP authority is noted in the permit as a “Title I Condition: SIP for (pollutant name) NAAQS,” clearly marking it as a SIP requirement. Title I conditions never expire, regardless of the overall status of the permit, allowing them to meet federal requirements for the permanence of SIP conditions.
The enforceable document is then referred to as the joint Title I/Title V or joint Title I/permit document, because Minnesota is establishing SIP limits through its Title I authority and issuing a permit through its Title V or permitting authority. (Title I and Title V are portions of the CAA.)
If limits or conditions are needed on a variety of sources, the MPCA would also consider rules to implement limits needed for the SIP.
Maintenance Areas, Ongoing SIP Requirements, and Updating the SIP
Maintenance areas are areas that were once in nonattainment with a NAAQS, but which are now meeting the NAAQS. States must submit a SIP in order for EPA to redesignate a nonattainment area to attainment, when it is then known as a maintenance area. In order for the redesignation request to be approved, the state must already have an approved SIP for that area. The state must also show current modeled attainment, two years of monitoring without a violation, maintenance plans for maintaining the NAAQS for at least ten years, and, in some cases, contingency plans outlining procedures the state will implement in the event that the area violates the NAAQS. The MPCA is required to submit, for EPA approval, a second updated maintenance plan eight years after the redesignation to attainment to ensure maintenance of the NAAQS for an additional ten years.
Even in nonattainment areas that have been reclassified to attainment and are now known as maintenance areas, sources must continue to comply with the limits established when the area was in nonattainment. The limits never expire, and can only be changed or removed through the previously described SIP revision process.
The official boundaries of Minnesota’s current maintenance areas are as follows:
- Carbon Monoxide:
- The area within the official city limits of the city of St. Cloud contained within Benton, Sherburne, and Stearns Counties
- City of Duluth
- Anoka, Hennepin, Ramsey, and portions of Carver, Dakota, Scott, Washington, and Wright Counties
- Sulfur Dioxide:
- Seven county Twin Cities Metropolitan Area (Anoka, Carver, Dakota, Hennepin, Ramsey, Scott, Washington)
- City of Rochester
- Particulate Matter (PM10):
- A portion of the city of Rochester, bounded on the south by U.S. Highway 14; on the west by U.S. Highway 52; on the north by 14th Street N.W. between U.S. Highway 52 and U.S. Route 63 (Broadway Avenue), U.S. Route 63 north to Northern Heights Drive, N.E. and Northern Heights Drive N.E. extended east to the 1990 city of Rochester limits; and on the east by the 1990 city of Rochester limits.
- A portion of the city of St. Paul bounded by the Mississippi River from Lafayette to Route 494, Route 494 east to Route 61, Route 61 north to I-94, I-94 west to Lafayette, and Lafayette south to the Mississippi River.
Modifications at Facilities with Site-Specific SIP Requirements
Sources that have site-specific SIP requirements may wish to make changes to their operations that require changes to either their Administrative Order or Title I SIP conditions in their permits. Compared to the general permit amendment process, this tends to be more complex and lengthy. Once approved and promulgated by the EPA, the SIP (of which the limits are a part) becomes federal rule. This means that every change made to an Order or Title I SIP condition in a permit must be public noticed at the state level, then submitted to and approved by EPA as a SIP revision, including going through the federal process of notice and comment in the Federal Register. This process can take over a year to complete, even for changes that would not otherwise be major amendments as defined under permitting rules. (All changes to SIP conditions must be major permit amendments.)
The MPCA’s policy of replacing Orders with federally enforceable air emission permits helps to alleviate some problems with the extended time frame. The permit can sometimes be written with more built-in operational flexibility than the original order, at least to the extent that changes to the facility that do not require a permit amendment are unlikely to require a SIP amendment. If the permit needs to be amended, the MPCA can usually give construction authorization through the permit so that the SIP amendment process and construction at the facility can occur in parallel. No additional public notice is necessary, provided that the public notice for the permit amendment includes a notice referring to pending changes in the SIP.
Modifications of Title I SIP Conditions
The MPCA and EPA have agreed to the following procedure for modifying site-specific SIP requirements in air quality permits:
- When the MPCA wants to modify a SIP requirement contained in the permit, MPCA will draft a permit amendment. Once the permit is drafted, EPA’s Title I SIP staff will be informed of pending SIP revisions, including the revised language and any supporting materials, and can comment if they find any problems with the Title I SIP language.
- The proposed permit amendment will include the new SIP conditions, with the caveat that these new SIP conditions will only become effective upon EPA approval of the SIP revision. The proposed permit amendment will continue to require compliance with the SIP requirements of the existing permit until the SIP is revised. (In other words, the company follows the “old” SIP requirements until EPA approves the “new” requirements into the SIP.) When the new requirements are approved, they become effective and the old requirements disappear.
- The proposed permit amendment will be public noticed as a permit revision and as a Title I SIP revision.
- In conjunction with the public participation process on the proposed permit and SIP amendments, the permit amendment will be sent to EPA for its 45-day permitting review. (Applies to Title V permits only).
- If EPA has no permitting objection to the proposed permit amendment, the MPCA will issue the permit amendment. Therefore, EPA’s permitting staff have not objected to the new SIP requirements, but also recognize and agree that they are not “applicable requirements” (under the permit) until the new requirements are approved into the SIP.
- The permit amendment is sent to EPA as a SIP revision.
- Once EPA SIP staff approve, and federal notice and comment procedures are complete, the Title I SIP conditions of the permit are incorporated into Minnesota’s SIP at the federal level.
More information
For questions regarding the State Implementation Plan, contact This e-mail address is being protected from spambots. You need JavaScript enabled to view it. , 651-757-2607.
For more information about the air program at the MPCA, see the following presentation:
