# Request for Information on 2,3-Pentanedione and Other Alpha-Diketones Used As Diacetyl Substitutes
**AGENCY:**
National Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention (CDC), Department of Health and Human Services (HHS).
**ACTION:**
Notice of public comment period.
**SUMMARY:**
The National Institute for Occupational Safety and Health (NIOSH) of the Centers for Disease Control and Prevention (CDC) intends to evaluate the scientific data on 2,3-pentanedione (CAS #600-14-6, also known as pentane-2,3-dione; acetyl propionyl) and other alpha-diketones and develop appropriate communication documents, such as a Current Intelligence Bulletin, Criteria Document and/or other informational products, and potentially establish a Recommended Exposure Limit (REL) for diacetyl substitutes. NIOSH is requesting information on the following: (1) Published and unpublished reports and findings from *in vitro* and *in vivo* toxicity studies with 2,3-pentanedione, and other alpha diketones, (2) information on possible health effects observed in workers exposed to 2,3-pentanedione, and other alpha-diketones, (3) information on workplaces and products in which 2,3-pentanedione and other alpha-diketones can be found, (4) description of work tasks and scenarios with a potential for exposure to 2,3-pentanedione and other alpha-diketones, (5) workplace exposure data, and (6) information on control measures ( *e.g.,* engineering controls, work practices, personal protective equipment) that are being used in workplaces where potential exposures to 2,3-pentanedione and other alpha diketones occur.
*Public Comment Period:* Comments must be received by February 9, 2011.
**ADDRESSES:**
You may submit comments, identified by docket number NIOSH-189 by any of the following methods:
• *Mail:* NIOSH Docket Office, Robert A. Taft Laboratories, MS-C34, 4676 Columbia Parkway, Cincinnati, OH 45226.
• *Facsimile:* (513) 533-8285.
• *E-mail: [email protected].*
All information received in response to this notice will be available for public examination and copying at the NIOSH Docket Office, Room 111, 4676 Columbia Parkway, Cincinnati, Ohio 45226. A complete electronic docket containing all comments submitted will be available on the NIOSH Web page at *http://www.cdc.gov/niosh/docket,* and comments will be available in writing by request. NIOSH includes all comments received without change in the docket, including any personal information provided.
**FOR FURTHER INFORMATION CONTACT:**
Lauralynn Taylor McKernan, NIOSH, Robert A Taft Laboratories, MS-C32, 4676 Columbia Parkway, Cincinnati, OH 45226, telephone: (513) 533-8542 *.*
**SUPPLEMENTARY INFORMATION:**
2,3-pentanedione is an alpha-diketone that has received attention as a substitute for diacetyl. 2,3-pentanedione is structurally very similar to diacetyl since 2,3-pentanedione is a 5-carbon alpha-diketone and diacetyl is a 4-carbon alpha-diketone. Published reports on the toxicity of 2,3-pentanedione are currently only in abstract form but suggest that in rats 2,3-pentanedione causes airway epithelial damage similar to that produced by diacetyl (Hubbs * et al.* 2010b; Morgan * et al.* 2010). Preliminary data also suggest that, under certain conditions, both diacetyl and 2,3-pentanedione can cause changes in the central nervous system (Hubbs * et al.* 2010a). Additional alpha-diketones of interest include, but are not limited to, those used in food manufacturing such as 2,3-hexanedione and 2,3-heptanedione (Kreiss * et al.* 2010).
NIOSH seeks to obtain materials, including published and unpublished reports and research findings, to evaluate the possible health risks of occupational exposure to 2,3-pentanedione and other alpha-diketones used as diacetyl substitutes. Examples of requested information include, but are not limited to, the following:
(1) Identification of industries or occupations in which exposures to 2,3-pentanedione, and other alpha-diketones used as diacetyl substitutes may occur;
(2) Trends in the production and use of 2,3-pentanedione, and other alpha-diketones;
(3) Description of work tasks and scenarios with a potential for exposure to 2,3-pentanedione, and other alpha-diketones used as diacetyl substitutes;
(4) Workplace exposure measurement data in various types of industries and jobs where 2,3-pentanedione, and other alpha-diketones are used;
(5) Case reports or other health information demonstrating potential health effects in workers exposed to 2,3-pentanedione, and other alpha-diketones;
(6) Research findings from *in vitro* and *in vivo* toxicity studies;
(7) Information on control measures ( *e.g.,* engineering controls, work practices, personal protective equipment) being taken to minimize worker exposure to 2,3-pentanedione, and other alpha-diketones used as diacetyl substitutes;
(8) Educational materials for worker safety and training on the safe handling of 2,3-pentanedione and other alpha-diketones; and
(9) Data pertaining to the feasibility of establishing a REL for 2,3-pentanedione, and other alpha-diketones.
**References**
Hubbs, A. F., Cumpston, A., Goldsmith, W. T., Battelli, L. A., Kashon, M. L., Jackson, M. C., Frazer, D. G., Fedan, J. S., Goravanahally, M. P., and Sriram, K. (2010a). Acute central neurotoxicity of inhaled alpha-diketon butter flavoring compounds in the rat brain. *Vet Path* 47(6), 57S.
Hubbs, A. F., Moseley, A. E., Goldsmith, W. T., Jackson, M. C., Kashon, M. L., Battelli, L. A., Schwegler-Berry, D., Goravanahally, M. P., Frazer, D., Fedan, J. S., Kreiss, K., and Castranova, V. (2010b). Airway epithelial toxicity of the flavoring agent, 2,3-pentanedione. *The Toxicologist: Supplement to Toxicological Sciences* 114(1), 319.
Kreiss, K., Day, G. A., Cummings, K. J., and Kullman, G. (2010). Diacetul substitutes in bakery product manufacture *Am J Respir Crit Care Med* 181(1), A4650.
Morgan, D. L., Kirby, P. J., Price, H. C., Bosquet, R. W., Taylor, G. J., Gage, N., and Flake, G. P. (2010). Inhalation toxicity of acetyl proprionyl in rats and mice. *The Toxicologist: Supplement to Toxicological Sciences* 114(1), 316.
John Howard,
Director, National Institute for Occupational Safety and Health, Centers for Disease Control and Prevention.