Mississippi v. EPA: Support of the Clean Air Science Advisory Committee is Not Necessary to Affirm EPA’s NAAQS

by Foley Hoag LLP - Environmental Law

On Tuesday, in Mississippi v. EPA, the Court of Appeals for the D.C. Circuit affirmed EPA’s 2008 NAAQS for ozone of 0.075 ppm.  However, it remanded EPA’s decision to set the secondary NAAQS, for public welfare, at the same 0.075 ppm level.  With respect to the primary standard, the Court gave short shrift to industry and red-state challenges that the standard was too stringent.  This is not surprising, since the Clean Air Science Advisory Committee had recommended a range of between 0.060 and 0.070 ppm.

The interesting part of the decision is the Court’s explanation of why it rejected environmental group and blue-state challenges which argued that the standard was not sufficiently protective, given the CASAC recommendation.  As this space has addressed in connection with judicial review of the PMSO2, and NOx NAAQS, the Court’s decisions in recent years have severely circumscribed EPA’s discretion to ignore CASAC.

I think it clear from this decision that CASAC support remains sufficient to justify the NAAQS set by EPA, but the Court has now carved out a narrow window where CASAC support is not necessary; EPA has some discretion to set an NAAQS outside of CASAC’s recommendation, so long as EPA clearly explains why it has rejected CASAC’s recommendation.  It may also be necessary that the basis for CASAC’s recommendation to be at least arguably ambiguous.

As the Court noted:

CASAC concluded that “the current primary 8-hr standard of 0.08 ppm needs to be substantially reduced to be protective of human health, particularly in sensitive subpopulations” and that the standard should be set within the range of 0.060 to 0.070 ppm. Id. at 4–5. CASAC reiterated this recommendation in a March 2007 letter to EPA, underscoring that “overwhelming scientific evidence” supported its recommendation “that the level of the current primary ozone standard should be lowered from 0.08 ppm to no greater than 0.070 ppm.”

Believe it or not, to the Court, this was not a sufficiently clear statement that CASAC believed that adverse health effects were in fact likely above 0.070 ppm.

Had CASAC reached a scientific conclusion that adverse health effects were likely to occur at the 0.070 ppm level, EPA’s failure to justify its uncertainty regarding the existence of adverse health effects at this level would be unacceptable.  …

But we are unable to determine whether CASAC reached any such scientific conclusion.  Although CASAC stated that “overwhelming scientific evidence” supported its recommendation that the standard be set no higher than 0.070 ppm, Mar. 2007 CASAC Letter, at 2, it never explained whether this proposal was based on its scientific judgment that adverse health effects would occur at that level or instead based on its more qualitative judgment that the range it proposed would be appropriately protective of human health with an adequate margin of safety.

I’m sorry, but does anyone doubt that, if CASAC were asked the precise question framed by the Court, its answer would have been that it indeed believed that adverse impacts are likely above 0.070 ppm?  It is difficult to see this decision other than as the Court trying really hard to preserve final decision-making authority for the EPA administrator.  I’m sympathetic to that view.  The Administrator is appointed by the President; CASAC members are not.  Nonetheless, I have a hard time buying the Court’s rationale here.

It may not matter much in the long run, because the evidence for a standard at or below 0.070 ppm has only gotten stronger.  So long as EPA does not propose a standard below natural background, the new standard, due late in 2014, is certainly not going to be above 0.070 ppm, and is likely to be affirmed – because it will be consistent with the CASAC recommendation.


Written by:

Foley Hoag LLP - Environmental Law

Foley Hoag LLP - Environmental Law on:

Readers' Choice 2017
Reporters on Deadline

"My best business intelligence, in one easy email…"

Your first step to building a free, personalized, morning email brief covering pertinent authors and topics on JD Supra:
Sign up using*

Already signed up? Log in here

*By using the service, you signify your acceptance of JD Supra's Privacy Policy.
Custom Email Digest
Privacy Policy (Updated: October 8, 2015):

JD Supra provides users with access to its legal industry publishing services (the "Service") through its website (the "Website") as well as through other sources. Our policies with regard to data collection and use of personal information of users of the Service, regardless of the manner in which users access the Service, and visitors to the Website are set forth in this statement ("Policy"). By using the Service, you signify your acceptance of this Policy.

Information Collection and Use by JD Supra

JD Supra collects users' names, companies, titles, e-mail address and industry. JD Supra also tracks the pages that users visit, logs IP addresses and aggregates non-personally identifiable user data and browser type. This data is gathered using cookies and other technologies.

The information and data collected is used to authenticate users and to send notifications relating to the Service, including email alerts to which users have subscribed; to manage the Service and Website, to improve the Service and to customize the user's experience. This information is also provided to the authors of the content to give them insight into their readership and help them to improve their content, so that it is most useful for our users.

JD Supra does not sell, rent or otherwise provide your details to third parties, other than to the authors of the content on JD Supra.

If you prefer not to enable cookies, you may change your browser settings to disable cookies; however, please note that rejecting cookies while visiting the Website may result in certain parts of the Website not operating correctly or as efficiently as if cookies were allowed.

Email Choice/Opt-out

Users who opt in to receive emails may choose to no longer receive e-mail updates and newsletters by selecting the "opt-out of future email" option in the email they receive from JD Supra or in their JD Supra account management screen.


JD Supra takes reasonable precautions to insure that user information is kept private. We restrict access to user information to those individuals who reasonably need access to perform their job functions, such as our third party email service, customer service personnel and technical staff. However, please note that no method of transmitting or storing data is completely secure and we cannot guarantee the security of user information. Unauthorized entry or use, hardware or software failure, and other factors may compromise the security of user information at any time.

If you have reason to believe that your interaction with us is no longer secure, you must immediately notify us of the problem by contacting us at info@jdsupra.com. In the unlikely event that we believe that the security of your user information in our possession or control may have been compromised, we may seek to notify you of that development and, if so, will endeavor to do so as promptly as practicable under the circumstances.

Sharing and Disclosure of Information JD Supra Collects

Except as otherwise described in this privacy statement, JD Supra will not disclose personal information to any third party unless we believe that disclosure is necessary to: (1) comply with applicable laws; (2) respond to governmental inquiries or requests; (3) comply with valid legal process; (4) protect the rights, privacy, safety or property of JD Supra, users of the Service, Website visitors or the public; (5) permit us to pursue available remedies or limit the damages that we may sustain; and (6) enforce our Terms & Conditions of Use.

In the event there is a change in the corporate structure of JD Supra such as, but not limited to, merger, consolidation, sale, liquidation or transfer of substantial assets, JD Supra may, in its sole discretion, transfer, sell or assign information collected on and through the Service to one or more affiliated or unaffiliated third parties.

Links to Other Websites

This Website and the Service may contain links to other websites. The operator of such other websites may collect information about you, including through cookies or other technologies. If you are using the Service through the Website and link to another site, you will leave the Website and this Policy will not apply to your use of and activity on those other sites. We encourage you to read the legal notices posted on those sites, including their privacy policies. We shall have no responsibility or liability for your visitation to, and the data collection and use practices of, such other sites. This Policy applies solely to the information collected in connection with your use of this Website and does not apply to any practices conducted offline or in connection with any other websites.

Changes in Our Privacy Policy

We reserve the right to change this Policy at any time. Please refer to the date at the top of this page to determine when this Policy was last revised. Any changes to our privacy policy will become effective upon posting of the revised policy on the Website. By continuing to use the Service or Website following such changes, you will be deemed to have agreed to such changes. If you do not agree with the terms of this Policy, as it may be amended from time to time, in whole or part, please do not continue using the Service or the Website.

Contacting JD Supra

If you have any questions about this privacy statement, the practices of this site, your dealings with this Web site, or if you would like to change any of the information you have provided to us, please contact us at: info@jdsupra.com.

- hide
*With LinkedIn, you don't need to create a separate login to manage your free JD Supra account, and we can make suggestions based on your needs and interests. We will not post anything on LinkedIn in your name. Or, sign up using your email address.