An equal opportunity employer 1220 L Street, Northwest Russell White Washington, DC 20005

- 4070 Health Sciences Manager Tel 202

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- 682

- 8270 whiter@api.org

March 8 , 201 3

Byron J. Bunker, Division Director Compliance Division Office of Transportation and Air Quality US Environmental Protection Agency 2000 Traverwood Drive Ann Arbor, Michigan 48105

RE: Interim Report # 24

– Fuels and Fuel Additives Health Effects Testing Regulation; Pursuant to Section 211(b)(2) and 211(e) of the Clean Air Act.

Dear Mr. Bunker :

The American Petroleum Institute (API), on behalf of the Secti on 211(b) Research Group is submitting this interim report on the progress and status between 01 J uly 2012 and 01 J anuary 201 3 of the testing program set forth in the Alternative Tier 2 provisions of the testing regulation.

1. Toxicology Testing 1

Baseline Gasoline Vapor Condensate :

 Subchronic study (with GFAP, genotoxicity, immunotoxicity, and neurotoxicity assays)

– The final report was submitted to EPA 05 July 2007.

 Two

- generation reproductive study

– The final report was submitted to EPA 23 January 2009.

 Rat and mouse developmental toxicity studies

– The rat final report was submitted to EPA 11 August 2008. The mouse final report was revised and resubmitted to EPA 23 November 2009.

 Chronic study

– T he final report was submitted to EPA 16 June 20 10

. Gasoline/MTBE Vapor Condensate :

 Subchronic study (with GFAP, genotoxicity, immunotoxicity, and neurotoxicity assays)

– The final report was submitted to EPA 14 September 2007.

 Two

- generation reproductive study

– The final report was submitted to EPA 07 July 2011.

 Rat and mouse developmental toxicity studies

– The final report of the rat study wa s submitted to EPA 07 July 2009

. The mouse final report was submitted to EPA 04 June 2009. The final report of the repeat mouse study was submitted to EPA 06 May 2010.

 Chronic study

– The final report was submitted to EPA 16 June 2010 . A report amendm ent was submitted to EPA on 21 April 2011

.

1 All studies were conducted in rats, unless otherwise notedMarch 8 , 201 3 Page 2 of 3 Gasoline/Ethanol Vapor Condensate:

 Subchronic study (with GFAP, genotoxicity, immunotoxicity , and neurotoxicity assays)

– The final report was submitted to EPA on 24 February 2 0 10.

 One

- generation reproductive toxicity study

– The final report was submitted to EPA 29 May 2009.

 Developmental toxicity study

- The final report was submitted to EPA 10 December 2008.

Gasoline/TAME Vapor Condensate:

 Subchronic study (with GFAP, genotoxicity, immunotoxicity, and neurotoxicity assays)

– The final report was submitted to EPA on 27 December 2011.

 One

- generation reproductive study

- The final report was submitted to EPA 29 May 2009.

 Developmental toxicity study

– The final report was submitted to EPA 17 December 2008.

Gasoline/ETBE Vapor Condensate:

 Subchronic study (with GFAP, genotoxicity, immunotoxicity, and neurotoxicity assays)

– The final report was submitted to EPA on 23 March 2011

.

 One

- generation reproductive study

– The final report was submitted to EPA 06 May 2010

.

 Developmental toxicity study

– The final report was submitted to EPA 17 D e cember 2008.

Gasoline/DIPE Vapor Condensate:

 Subchronic study (with GFAP, genotoxicity, immunotoxi city, and neurotoxicity assays)

– EPA approved the second draft report 14 September 2012.

 One

- generation reproductive study

- The final report was submitted to EPA 02 September 2011

.

 Developmental toxicity study

– The final report was submitted to EPA 15 November 2012.

Gasoline/TBA Vapor Condensate:

 Subchronic study (with GFAP, genotoxicity, immunotoxic ity, and neurotoxicity assays)

– EPA approved the second draft report 14 September 2012.

 One

- generation reproductive study

- The final report was submitted to EPA 02 September 2011

.

 Developmental toxicity stud y

- The final report was submitted to EPA 16 October 2009.

Pharmacokinetic Studies on DIPE, ETBE, and TBA :

 ETBE

– Preparation of the first draft report was in progress.

 DIPE

– T he in

- life studies were completed in October 2012

. Preparation of the f irst draft report was in progress.

 TBA

– The final report of the pilot study was submitted to EPA 31 August 2012. The definitive study was cancelled by the Company with EPA registration for TBA.March 8 , 201 3 Page 3 of 3

2. Exposure Screening Studies

T he report entitled “ Section 211(B) Tier 2 High End Exposure Study of Conventional and Oxygenated Gasoline ” and previously submitted associated materials were accepted by EPA on 1 9 May 2010

. A compiled version of the final r eport was submitted to EPA on 10 June 2011, completing the Section 211(B) Tier 2 exposure screening study requir e ments.

Sincerely,

Russell White, Ph.D. Health Sciences Manager

cc: Joe Sopata, EPA (via email)