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                -                       the agency docket number / agency internal file number                    
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###### Environmental Protection Agency

          - 40 CFR Part 82
          - [EPA-HQ-OAR-2004-0488; FRL-8956-5]

# AGENCY:

Environmental Protection Agency (EPA).

# ACTION:

Data availability.

# SUMMARY:

                        Under section 612 of the Clean Air Act, the Environmental Protection Agency (EPA) reviews and lists as acceptable alternatives to ozone-depleting substances (ODS). In 2006, EPA proposed to list R-744 (CO2) as “acceptable with use conditions” as a substitute for CFC-12 in the motor vehicle air conditioning (MVAC) end-use within the refrigeration and air-conditioning sector. When using CO2                         as a refrigerant, MVAC systems would be required to use the refrigerant according to those legally enforceable conditions. EPA proposed use conditions because of the potential risk of exposure to elevated concentrations of CO2                         within the passenger compartment if there was a leak of the MVAC system. Elevated CO2                         levels could cause passengers, and of particular concern, the driver, to become drowsy. Since the time of the proposed rule, additional information regarding the effects of short-term CO2                         exposures has become available and EPA is now making that information available to the public. As noted in the proposed rule, EPA is considering whether to establish a breathing zone ceiling and this short-term exposure information is relevant to EPA's decision on this issue. In addition, EPA is providing the public with opportunity to respond to an issue raised in a public comment on the proposed rule.                    

# DATES:

Comments must be received on or before November 16, 2009.

# ADDRESSES:

Submit your comments, identified by Docket ID No. EPA-HQ-OAR-2004-0488, by one of the following methods:
      -  http://www.regulations.gov : Follow the on-line instructions for submitting comments.                    
      -  E-mail: a-and-r-Docket@epa.gov .                    
      -  Fax:                          202-566-1741.                    
      -  Mail:                          EPA Docket Center (EPA/DC), Mailcode 6102T, Attention Docket ID No. EPA-HQ-OAR-2004-0488, 1200 Pennsylvania Avenue, NW.,  Washington, DC 20460.                    
      -  Hand Delivery:                          Public Reading Room, Room 3334,  EPA West Building, 1301 Constitution Avenue, NW., Washington, DC.                    

*Instructions:*                         Direct your comments to Docket ID No. EPA-HQ-OAR-2004-0488. EPA's policy is that all comments received will be included in the public docket without change and may be made available online at                         *http://www.regulations.gov*, including any personal information provided, unless the comment includes information claimed to be Confidential Business Information (CBI) or other information whose disclosure is restricted by statute. Do not submit information that you consider to be CBI or otherwise protected through                         *http://www.regulations.gov*                         or e-mail. The                         *http://www.regulations.gov*                         Web site is an “anonymous access” system, which means EPA will not know your identity or contact information unless you provide it in the body of your comment. If you send an e-mail comment directly to EPA without going through                         *http://www.regulations.gov*                         your e-mail address will be automatically captured and included as part of the comment that is placed in the public docket and made available on the Internet. If you submit an electronic comment, EPA recommends that you include your name and other contact information in the body of your comment and with any disk or CD-ROM you submit. If EPA cannot read your comment due to technical difficulties and cannot contact you for clarification, EPA may not be able to consider your comment. Electronic files should avoid the use of special characters, any form of encryption, and be free of any defects or viruses.                    

*Docket:*                         All documents in the docket are listed in the                         *http://www.regulations.gov*                         index. Although listed in the index, some information is not publicly available,                         *e.g.*, CBI or other information whose disclosure is restricted by statute. Certain other material, such as copyrighted material, will be publicly available only in hard copy. Publicly available docket materials are available either electronically in                         *http://www.regulations.gov*                         or in hard copy at the Air Docket, EPA/DC, EPA West, Room 3334, 1301 Constitution Ave., NW., Washington, DC. This Docket Facility is open from 8:30 a.m. to 4:30 p.m., Monday through Friday, excluding legal holidays. The telephone number for the Public Reading Room is (202) 566-1744, and the telephone number for the Air Docket is (202) 566-1742.                    

# FOR FURTHER INFORMATION CONTACT:

                        Melissa Fiffer, Stratospheric Protection Division, Office of Atmospheric                               ( print page 47775)                            Programs (6205J), Environmental Protection Agency, 1200 Pennsylvania Ave.,  NW., Washington, DC 20460,                         *telephone number:*                         (202) 343-9464,                         *fax number:*                         (202) 343-2363;                         *e-mail address: fiffer.melissa@epa.gov.*

# SUPPLEMENTARY INFORMATION:

## Outline

1. What is today's action?

2. What information is EPA making available for review and comment?

3. Where can I get the information?

4. What is EPA taking comment on and what supporting documentation do I need to include in my comments?

5. What should I consider as I prepare my comments for EPA?

## 1. What is today's action?

                    This notice of data availability (NODA) makes available to the public a human health effects review of R-744 (CO2) that EPA will consider as it moves forward to address its proposed “acceptable subject to use conditions” listing for R-744 in MVACs. In the proposed rule (71 FR 55140), EPA noted that a maximum CO2                     concentration never to be exceeded (“ceiling limit”) in the space where people breathe (“breathing zone”) may be needed in addition to the proposed CO2                     exposure limit of 3.0% by volume averaged over 15 minutes. A breathing zone ceiling limit may provide additional assurance regarding vehicle driver alertness. EPA subsequently hired a contractor to examine the human health effects of elevated CO2                     concentrations within the confined space of a vehicle passenger compartment. Today we are making available for comment the contractor-authored memo on ceiling limits for R-744 in the passenger compartment space of a motor vehicle. This memo reflects the latest information on short-term exposure to R-744 in an enclosed space.                

                    In 2006, EPA proposed to amend the acceptability of R-744 to include the use condition that MVAC systems must be designed to avoid occupant exposure to concentrations above the CO2                     short-term exposure limit of 3% averaged over 15 minutes. In the proposal, EPA also suggested including a ceiling limit within the 3% average limit. Based on the analysis in the contractor-author memo made available today, EPA is considering a ceiling limit of 4% R-744, or 40,000 parts per million (ppm). This ceiling limit could not be exceeded for any duration inside the passenger compartment.                

In addition, during the public comment period, one commenter suggested that the proposed use conditions should be clarified to address whether the same standard applies or whether a requirement even applies when the motor vehicle ignition is off.

## 2. What information is EPA making available for review and comment?

                    EPA is making available, for review and comment, a contractor-authored memo on the toxicological impacts of short-term exposure to CO2                     in the confined space of a vehicle passenger compartment, “Review of Health Impacts from Short-Term Carbon Dioxide Inhalation Exposures,” as well as the papers cited in the memo. This memo provides information concerning a ceiling limit for the passenger compartment of vehicles using R-744 in MVAC systems. In addition, the public comment concerning application of the proposed use conditions when the ignition is off is available in the public docket as item EPA-HQ-OAR-2004-0488-35.1.                

## 3. Where can I get the information?

                    All of the information can be obtained through the Air Docket and at                     *http://www.regulations.gov*                     (                    *see***ADDRESSES**                     section above for docket contact information).                

## 4. What is EPA taking comment on and what supporting documentation do I need to include in my comments?

*EPA is only accepting comment on two topics:*

1. Whether EPA should include a ceiling limit of 4% R-744, or 40,000 ppm, in the final rule on the use of R-744 in new MVAC systems, in addition to the short-term exposure limit of 3% averaged over 15 minutes, and

2. Whether the proposed use conditions on R-744 in new MVAC systems should apply when the ignition is off.

Commenters may provide any published studies or supporting statements. At this time, EPA is not requesting comments of a general or editorial nature. EPA is not accepting comments more generally on the proposed listing of R-744 as acceptable with use conditions. Interested readers are directed to 71 FR 55140 for additional information regarding EPA's proposed listing of R-744 as acceptable with use conditions in the MVAC sector.

## 5. What should I consider as I prepare my comments for EPA?

*You may find the following suggestions helpful for preparing your comments:*

1. Explain your views as clearly as possible.

2. Describe any assumptions that you used.

3. Provide any technical information or data you used that support your views.

4. Provide specific examples to illustrate your concerns.

5. Make sure to submit your comments by the comment period deadline identified.

6. To ensure proper receipt by EPA, identify the appropriate docket identification number in the subject line on the first page of your response. It would also be helpful if you provided the name, date, and Federal Register citation related to your comments.

# List of Subjects in 40 CFR Part 82

      - Environmental protection
      - Administrative practice and procedure
      - Air pollution control
      - Reporting and recordkeeping requirements

Dated: August 14, 2009.

Brian J. McLean,

Director, Office of Atmospheric Programs.

[FR Doc. E9-22425 Filed 9-16-09; 8:45 am]

BILLING CODE 6560-50-P