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Occupational Safety and Health Administration


RIN: 1218-AC33

Publication ID: Fall 2010

Title: Occupational Exposure to Food Flavorings Containing Diacetyl and Diacetyl Substitutes

Abstract: On July 26, 2006, the United Food and Commercial Workers International Union (UFCW) and the International Brotherhood of Teamsters (IBT) petitioned DOL for an Emergency Temporary Standard (ETS) for all employees exposed to diacetyl, a major component in artificial butter flavoring. Diacetyl and a number of other volatile organic compounds are used to manufacture artificial butter food flavorings. These food flavorings are used by various food manufacturers in a multitude of food products including microwave popcorn, certain bakery goods, and some snack foods. OSHA denied the petition on September 25, 2007, but has initiated 6(b) rulemaking. Evidence from NIOSH and other sources indicated that employee exposure to diacetyl and food flavorings containing diacetyl is associated with bronchiolitis obliterans, a debilitating and potentially fatal disease of the small airways in the lung. Severe obstructive airway disease has been observed in the microwave popcorn industry and in food flavoring manufacturing plants. Experimental evidence has shown that inhalation exposure to artificial butter flavoring vapors and diacetyl damaged tissue lining the nose and airways of rats and mice. OSHA published an Advanced Notice of Proposed Rulemaking (ANPRM) on January 21, 2009, but withdrew the ANPRM on March 17, 2009, in order to facilitate timely development of a standard. The Agency subsequently initiated review of the draft proposed standard in accordance with the Small Business Regulatory Enforcement Fairness Act (SBREFA). The SBREFA Panel Report was completed on July 2, 2009. The occurrence of severe lung disease among workers in workplaces where diacetyl is manufactured and used has led some manufacturers to reduce or eliminate the amount of diacetyl in some kinds of flavorings, foods, and beverages. They have begun to use substitutes such as 2,3-pentanedione. These substitutes, some of which are structurally similar to diacetyl, have not been well-studied and there is growing concern that they also pose health risks for workers. Research on 2,3-pentanedione conducted by NIOSH and NIEHS suggests that, in rats, 2,3-pentanedione causes airway damage similar to that produced by diacetyl. NIOSH is currently developing a criteria document on occupational exposure to diacetyl. The criteria document will also address exposure to 2,3-pentanedione. It will include an assessment of the effects of exposure as well as quantitative risk assessment. OSHA intends to rely on these portions of the criteria document for the health effects analysis and quantitative risk assessment for the Agency's diacetyl rulemaking. NIOSH will initiate public peer review of the criteria document in April, 2011.

Agency: Department of Labor(DOL)

Priority: Other Significant

RIN Status: Previously published in the Unified Agenda

Agenda Stage of Rulemaking: Prerule Stage

Major: No

Unfunded Mandates: No

CFR Citation: 29 CFR 1910 (To search for a specific CFR, visit the Code of Federal Regulations.)

Legal Authority: 29 USC 655(b); 29 USC 657

Legal Deadline: None




FR Cite

Stakeholder Meeting


72 FR 54619



74 FR 3937

ANPRM Withdrawn


74 FR 11329

ANPRM Comment Period End



Completed SBREFA Report



Initiate Peer Review of Health Effects and Risk Assessment



Regulatory Flexibility Analysis Required: Yes

Government Levels Affected: None

Small Entities Affected: Businesses

Federalism: No

Included in the Regulatory Plan: No

RIN Data Printed in the FR: Yes

Agency Contact:
Dorothy Dougherty
Director, Directorate of Standards and Guidance
Department of Labor
Occupational Safety and Health Administration
200 Constitution Avenue NW., FP Building, Room N-3718,
Washington, DC 20210
Phone:202 693-1950
Fax:202 693-1678