United States: Which Way Is The Wind Blowing? U.S. Supreme Court Upholds EPA’s Cross-State Air Pollution Rule

On April 29, 2014, the U.S. Supreme Court issued a decision upholding EPA's Cross-State Air Pollution Rule (also known as the Transport Rule). The Transport Rule restricts air emissions from upwind states that in EPA's judgment contribute significantly to nonattainment of the National Ambient Air Quality Standards (NAAQS) in downwind states. According to EPA's regulatory impact analysis, the Rule is expected to have significant cost implications for electric generating utilities, and much of the costs could occur in Midwestern and Southern states that were identified in the Transport Rule as contributing to nonattainment of the NAAQS for states along the East Coast.

The Transport Rule was promulgated pursuant to what is often called the "Good Neighbor" provision of the Clean Air Act. In the Rule, EPA established a two-step approach for restricting emissions in upwind states. First, EPA used air modeling to determine which upwind states contributed more than one percent to the NAAQS for 8-hour ozone and PM2.5 in downwind states. Second, EPA determined the level of emission reductions that could be achieved in downwind states based on cost estimates for reducing emissions. For example, EPA concluded that significant emission reductions could be obtained for a cost of $500 per ton of NOx reduced, but that at greater than $500 per ton the emission reductions were minimal. The Agency then translated those cost estimates into the amount of emissions that upwind states would be required to eliminate. Lastly, EPA developed a Federal Implementation Plan (FIP) detailing how states were to comply with the emission budgets assigned under the Transport Rule.

As we previously reported in August 2012, the Transport Rule had been struck down by the U.S. Court of Appeals for the District of Columbia on Aug. 21, 2012. The Court of Appeals struck down the rule primarily for two reasons. First, the court found the cost estimates that EPA used as a basis to justify emission reductions would in some cases result in requirements for upwind states to reduce their emissions more than necessary to eliminate "significant" contributions to nonattainment in downwind states. The court held that EPA could only require reductions proportionate to a specific upwind state's contribution to a downwind state's nonattainment status. Second, the court held that states should have been given an opportunity to develop their own implementation plans before EPA required states to follow the FIP in the Transport Rule.

In reversing the Court of Appeals, the U.S. Supreme Court concluded that the Clean Air Act does not require EPA to mandate only proportionate reductions in emissions from upwind states. The court argued that the "proportionality approach could scarcely be satisfied in practice" because there are multiple upwind states that each affect multiple downwind states. The Court concluded that the proportionality approach would mean that "each upwind State will be required to reduce emissions by the amount necessary to eliminate that State's largest downwind contribution," but that would result in cumulative emission reductions and "costly overregulation." The court also concluded that it was appropriate for EPA to use cost as a means of allocating emissions, instead of the proportionality approach favored by the D.C. Circuit.

Regarding the FIP approach, the court held that after EPA issues a NAAQS, each state is required to propose a State Implementation Plan (SIP), including requirements to satisfy the Good Neighbor provision of the Clean Air Act. Therefore, the Court held it was appropriate for EPA to establish a FIP because the statutory deadline to propose SIPs that complied with the Good Neighbor provision had passed. The court rejected the D.C. Circuit's conclusion that it was premature to establish a FIP before EPA had made a determination regarding each upwind state's contribution to downwind states' nonattainment.

Supreme Court Justice Antonin Scalia, joined by Justice Clarence Thomas, authored a dissent in the case agreeing with the D.C. Circuit that costs are not contemplated as a basis for reducing emissions under the Good Neighbor provision. Further, the dissent addressed the majority opinion's assertion that the proportionality approach would result in "costly overregulation." The dissent stated, "over-control is no more likely to occur when the required reductions are apportioned among upwind States on the basis of amounts of pollutants contributed than when they are apportioned on the basis of cost." The dissent went on to note, "the solution to over-control under a proportional-reduction system is not difficult to discern. In calculating good-neighbor responsibilities, EPA . . . would set upwind States' obligations at levels that, after taking into account those reductions, suffice to produce attainment in all downwind States. Doubtless, there are multiple ways for the Agency to accomplish that task in accordance with the statute's amounts-based, proportional focus."

At this juncture, it is unclear whether EPA will need to promulgate additional rules to implement the Transport Rule as many of the Transport Rules' deadlines have already expired. Additionally, it is unclear whether other legal challenges to the Transport Rule, including challenges to whether the Rule satisfies regional haze emission requirements, will delay final implementation of the Rule. Those challenges have been stayed since the D.C. Circuit Court of Appeals vacated the rule in 2012 but appear to be able to proceed now that the vacatur has been overturned by the U.S. Supreme Court. There are also questions as to whether the Transport Rule, which was designed to help meet the 1997 ozone NAAQs of 80 ppb, will need to be reworked by EPA to meet the stricter 2008 ozone NAAQs of 75 ppb. It is also possible that estimates of emission cuts expected from the original the Transport Rule will change given the move by several power plants to convert from coal to natural gas in recent years.

A copy of the U.S. Supreme Court's decision is available here.

The content of this article is intended to provide a general guide to the subject matter. Specialist advice should be sought about your specific circumstances.

To print this article, all you need is to be registered on Mondaq.com.

Click to Login as an existing user or Register so you can print this article.

In association with
Related Video
Up-coming Events Search
Font Size:
Mondaq on Twitter
Register for Access and our Free Biweekly Alert for
This service is completely free. Access 250,000 archived articles from 100+ countries and get a personalised email twice a week covering developments (and yes, our lawyers like to think you’ve read our Disclaimer).
Email Address
Company Name
Confirm Password
Mondaq Topics -- Select your Interests
 Law Performance
 Law Practice
 Media & IT
 Real Estate
 Wealth Mgt
Asia Pacific
European Union
Latin America
Middle East
United States
Worldwide Updates
Check to state you have read and
agree to our Terms and Conditions

Terms & Conditions and Privacy Statement

Mondaq.com (the Website) is owned and managed by Mondaq Ltd and as a user you are granted a non-exclusive, revocable license to access the Website under its terms and conditions of use. Your use of the Website constitutes your agreement to the following terms and conditions of use. Mondaq Ltd may terminate your use of the Website if you are in breach of these terms and conditions or if Mondaq Ltd decides to terminate your license of use for whatever reason.

Use of www.mondaq.com

You may use the Website but are required to register as a user if you wish to read the full text of the content and articles available (the Content). You may not modify, publish, transmit, transfer or sell, reproduce, create derivative works from, distribute, perform, link, display, or in any way exploit any of the Content, in whole or in part, except as expressly permitted in these terms & conditions or with the prior written consent of Mondaq Ltd. You may not use electronic or other means to extract details or information about Mondaq.com’s content, users or contributors in order to offer them any services or products which compete directly or indirectly with Mondaq Ltd’s services and products.


Mondaq Ltd and/or its respective suppliers make no representations about the suitability of the information contained in the documents and related graphics published on this server for any purpose. All such documents and related graphics are provided "as is" without warranty of any kind. Mondaq Ltd and/or its respective suppliers hereby disclaim all warranties and conditions with regard to this information, including all implied warranties and conditions of merchantability, fitness for a particular purpose, title and non-infringement. In no event shall Mondaq Ltd and/or its respective suppliers be liable for any special, indirect or consequential damages or any damages whatsoever resulting from loss of use, data or profits, whether in an action of contract, negligence or other tortious action, arising out of or in connection with the use or performance of information available from this server.

The documents and related graphics published on this server could include technical inaccuracies or typographical errors. Changes are periodically added to the information herein. Mondaq Ltd and/or its respective suppliers may make improvements and/or changes in the product(s) and/or the program(s) described herein at any time.


Mondaq Ltd requires you to register and provide information that personally identifies you, including what sort of information you are interested in, for three primary purposes:

  • To allow you to personalize the Mondaq websites you are visiting.
  • To enable features such as password reminder, newsletter alerts, email a colleague, and linking from Mondaq (and its affiliate sites) to your website.
  • To produce demographic feedback for our information providers who provide information free for your use.

Mondaq (and its affiliate sites) do not sell or provide your details to third parties other than information providers. The reason we provide our information providers with this information is so that they can measure the response their articles are receiving and provide you with information about their products and services.

If you do not want us to provide your name and email address you may opt out by clicking here .

If you do not wish to receive any future announcements of products and services offered by Mondaq by clicking here .

Information Collection and Use

We require site users to register with Mondaq (and its affiliate sites) to view the free information on the site. We also collect information from our users at several different points on the websites: this is so that we can customise the sites according to individual usage, provide 'session-aware' functionality, and ensure that content is acquired and developed appropriately. This gives us an overall picture of our user profiles, which in turn shows to our Editorial Contributors the type of person they are reaching by posting articles on Mondaq (and its affiliate sites) – meaning more free content for registered users.

We are only able to provide the material on the Mondaq (and its affiliate sites) site free to site visitors because we can pass on information about the pages that users are viewing and the personal information users provide to us (e.g. email addresses) to reputable contributing firms such as law firms who author those pages. We do not sell or rent information to anyone else other than the authors of those pages, who may change from time to time. Should you wish us not to disclose your details to any of these parties, please tick the box above or tick the box marked "Opt out of Registration Information Disclosure" on the Your Profile page. We and our author organisations may only contact you via email or other means if you allow us to do so. Users can opt out of contact when they register on the site, or send an email to unsubscribe@mondaq.com with “no disclosure” in the subject heading

Mondaq News Alerts

In order to receive Mondaq News Alerts, users have to complete a separate registration form. This is a personalised service where users choose regions and topics of interest and we send it only to those users who have requested it. Users can stop receiving these Alerts by going to the Mondaq News Alerts page and deselecting all interest areas. In the same way users can amend their personal preferences to add or remove subject areas.


A cookie is a small text file written to a user’s hard drive that contains an identifying user number. The cookies do not contain any personal information about users. We use the cookie so users do not have to log in every time they use the service and the cookie will automatically expire if you do not visit the Mondaq website (or its affiliate sites) for 12 months. We also use the cookie to personalise a user's experience of the site (for example to show information specific to a user's region). As the Mondaq sites are fully personalised and cookies are essential to its core technology the site will function unpredictably with browsers that do not support cookies - or where cookies are disabled (in these circumstances we advise you to attempt to locate the information you require elsewhere on the web). However if you are concerned about the presence of a Mondaq cookie on your machine you can also choose to expire the cookie immediately (remove it) by selecting the 'Log Off' menu option as the last thing you do when you use the site.

Some of our business partners may use cookies on our site (for example, advertisers). However, we have no access to or control over these cookies and we are not aware of any at present that do so.

Log Files

We use IP addresses to analyse trends, administer the site, track movement, and gather broad demographic information for aggregate use. IP addresses are not linked to personally identifiable information.


This web site contains links to other sites. Please be aware that Mondaq (or its affiliate sites) are not responsible for the privacy practices of such other sites. We encourage our users to be aware when they leave our site and to read the privacy statements of these third party sites. This privacy statement applies solely to information collected by this Web site.

Surveys & Contests

From time-to-time our site requests information from users via surveys or contests. Participation in these surveys or contests is completely voluntary and the user therefore has a choice whether or not to disclose any information requested. Information requested may include contact information (such as name and delivery address), and demographic information (such as postcode, age level). Contact information will be used to notify the winners and award prizes. Survey information will be used for purposes of monitoring or improving the functionality of the site.


If a user elects to use our referral service for informing a friend about our site, we ask them for the friend’s name and email address. Mondaq stores this information and may contact the friend to invite them to register with Mondaq, but they will not be contacted more than once. The friend may contact Mondaq to request the removal of this information from our database.


From time to time Mondaq may send you emails promoting Mondaq services including new services. You may opt out of receiving such emails by clicking below.

*** If you do not wish to receive any future announcements of services offered by Mondaq you may opt out by clicking here .


This website takes every reasonable precaution to protect our users’ information. When users submit sensitive information via the website, your information is protected using firewalls and other security technology. If you have any questions about the security at our website, you can send an email to webmaster@mondaq.com.

Correcting/Updating Personal Information

If a user’s personally identifiable information changes (such as postcode), or if a user no longer desires our service, we will endeavour to provide a way to correct, update or remove that user’s personal data provided to us. This can usually be done at the “Your Profile” page or by sending an email to EditorialAdvisor@mondaq.com.

Notification of Changes

If we decide to change our Terms & Conditions or Privacy Policy, we will post those changes on our site so our users are always aware of what information we collect, how we use it, and under what circumstances, if any, we disclose it. If at any point we decide to use personally identifiable information in a manner different from that stated at the time it was collected, we will notify users by way of an email. Users will have a choice as to whether or not we use their information in this different manner. We will use information in accordance with the privacy policy under which the information was collected.

How to contact Mondaq

You can contact us with comments or queries at enquiries@mondaq.com.

If for some reason you believe Mondaq Ltd. has not adhered to these principles, please notify us by e-mail at problems@mondaq.com and we will use commercially reasonable efforts to determine and correct the problem promptly.