3938 Federal Register / Vol. 74, No. 12 / Wednesday, January 21, 2009 / Proposed Rules 

DEPARTMENT OF LABOR 

Occupational Safety and Health 

Administration 

29 CFR Part 1910 

[Docket No. OSHA–2008–0046] 

RIN 1218–AC33 

Occupational Exposure to Diacetyl and 

Food Flavorings Containing Diacetyl 

AGENCY: Occupational Safety and Health 

Administration (OSHA), Department of 

Labor. 

ACTION: Advance notice of proposed 

rulemaking. 

SUMMARY: OSHA is requesting data, 

information, and comment on issues 

related to occupational exposure to 

diacetyl and food flavorings containing 

diacetyl, including current employee 

exposures to diacetyl; the relationship 

between exposure to diacetyl and the 

development of adverse health effects; 

exposure assessment and monitoring 

methods; exposure control methods; 

employee training; medical surveillance 

for adverse health effects related to 

diacetyl exposure; and other pertinent 

subjects. In this notice, OSHA intends 

the term ‘‘diacetyl and food flavorings 

containing diacetyl’’ to encompass other 

constituents of food flavorings 

containing diacetyl. In addition to 

information on diacetyl, OSHA seeks 

information on acetoin, acetaldehyde, 

acetic acid, furfural, and other 

compounds present in food flavorings 

that may cause or contribute to 

flavoring-related lung disease. The 

Agency is also interested in and seeks 

information about diacetyl present in 

substances other than food flavorings 

(e.g., naturally occurring diacetyl or 

diacetyl in fragrances) as well as 

substitutes used in place of diacetyl 

(e.g., diacetyl trimer). The information 

received in response to this document 

will assist the Agency in developing a 

proposed standard addressing 

occupational exposure to diacetyl and 

food flavorings containing diacetyl. 

DATES: Comments must be submitted 

(postmarked, sent, or received) by April 

21, 2009. 

ADDRESSES: You may submit comments, 

identified by Docket No. OSHA–2008– 

0046, by any of the following methods: 

Electronically: You may submit 

comments and attachments 

electronically at http:// 

www.regulations.gov, which is the 

Federal eRulemaking Portal. Follow the 

instructions online for submitting 

comments. 

Fax: If your comments, including 

attachments, do not exceed 10 pages, 

you may fax them to the OSHA Docket 

Office at 202–693–1648. 

Mail, hand delivery, express mail, 

messenger or courier service: You must 

submit three copies of your comments 

and attachments to the OSHA Docket 

Office, Docket No. OSHA–2008–0046, 

Room N–2625, U.S. Department of 

Labor, 200 Constitution Avenue, NW., 

Washington, DC 20210; telephone 202– 

693–2350 (TTY number 877–889–5627). 

Deliveries (hand, express mail, 

messenger or courier service) are 

accepted during the Department of 

Labor’s and Docket Office’s normal 

business hours, 8:15 a.m.–4:45 p.m., e.t. 

Instructions: All submissions must 

include the Agency name and the OSHA 

docket number (Docket No. OSHA– 

2008–0046). Because of security-related 

procedures, submissions by regular mail 

may result in significant delay in their 

receipt. Please contact the OSHA Docket 

Office at the above address for 

information about security procedures 

for submitting comments by hand 

delivery, express delivery, and 

messenger or courier service. 

All comments, including any personal 

information you provide, are placed in 

the public docket without change and 

may be made available online at 

http://www.regulations.gov. Therefore, 

OSHA cautions you about submitting 

certain personal information, such as 

social security numbers and birthdates. 

For further information on submitting 

comments, see the ‘‘Public 

Participation’’ heading in the 

SUPPLEMENTARY INFORMATION section of 

this document. 

Docket: To read or download 

comments submitted in response to this 

Federal Register notice or other 

materials in the docket, go to Docket No. 

OSHA–2008–0046 at http:// 

www.regulations.gov or the OSHA 

Docket Office at the address above. All 

documents in the docket are listed in 

the http://www.regulations.gov index, 

however, some information (for 

example, copyrighted material) is not 

publicly available to read or download 

through the Web site. All submissions, 

including copyrighted material, are 

available for inspection and copying at 

the OSHA Docket Office. 

Electronic copies of this Federal 

Register notice are available at http:// 

www.regulations.gov. This notice, as 

well as news releases and other relevant 

information, also are available at 

OSHA’s Web site at http:// 

www.osha.gov. 

FOR FURTHER INFORMATION CONTACT: 

Press Inquiries: Jennifer Ashley, 

OSHA Office of Communications, Room 

N–3647, U.S. Department of Labor, 200 

Constitution Avenue, NW., Washington, 

DC 20210; telephone: 202–693–1999. 

General and Technical Information: 

David O’Connor, OSHA Directorate of 

Standards and Guidance, Office of 

Chemical Hazards—Non-Metals, Room 

N–3718, U.S. Department of Labor, 200 

Constitution Avenue, NW., Washington, 

DC 20210; telephone 202–693–2090. 

SUPPLEMENTARY INFORMATION: 

Table of Contents 

I. Background 

A. Events Leading to This Action 

B. Properties and Uses 

C. Health Effects Studies of Exposure to 

Butter Flavorings and Diacetyl 

II. Request for Data, Information, and 

Comment 

A. Production and Uses 

B. Employee Exposure 

C. Health Effects 

D. Risk Assessment 

E. Exposure Assessment and Monitoring 

Methods 

F. Control Measures 

G. Employee Training 

H. Medical Surveillance Programs 

I. Environmental Impacts 

J. Economic Impacts 

K. Impacts on Small Entities 

L. Duplication/Overlapping/Conflicting 

Rules 

M. Approaches to Regulation 

III. Public Participation 

IV. References 

V. Authority and Signature 

In this document, OSHA references a 

number of supporting materials, and 

includes a list of these materials (see 

Section IV—References). These 

materials are posted in Docket No. 

OSHA–2008–0046. See ADDRESSES

section above and Section III (Public 

Participation) for further information 

about accessing exhibits referenced in 

this Federal Register notice. 

I. Background 

A. Events Leading to This Action 

On July 26, 2006, the United Food 

and Commercial Workers International 

Union and the International 

Brotherhood of Teamsters petitioned 

OSHA for an Emergency Temporary 

Standard (ETS) covering all employees 

exposed to diacetyl. The petition cited 

evidence from NIOSH Health Hazard 

Evaluations to show that some 

employees exposed to butter flavorings 

developed bronchiolitis obliterans, a 

serious and sometimes fatal lung 

disease. OSHA denied the ETS petition 

on September 25, 2007, indicating that 

the evidence available at that time did 

not support the stringent legal findings 

required for an ETS. However, the 


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Agency acknowledged that the available 

evidence showed that employees 

exposed to butter flavoring vapors 

containing diacetyl may be at risk of 

material impairment, and initiated 

rulemaking under Section 6(b) of the 

Occupational Safety and Health Act of 

1970 (29 U.S.C. 651, 655). 

The information available to date 

indicates that regulating occupational 

exposures to diacetyl and food 

flavorings containing diacetyl presents a 

number of complex and difficult issues. 

Flavorings, including butter flavoring, 

are complex mixtures and may contain 

a number of potential airway reactive 

substances (e.g., diacetyl, acetoin, 

acetaldehyde, acetic acid, furfural). 

Diacetyl has been used as an indicator 

of exposure to butter flavoring vapors in 

a variety of occupational studies in 

microwave popcorn plants. While there 

is evidence that diacetyl is a factor in 

flavoring-related airway injury, other 

compounds may contribute to the 

development of obstructive airway 

disease and bronchiolitis obliterans. 

Gaps also exist in the available data on 

current usage of and exposure to 

diacetyl and food flavorings containing 

diacetyl. 

As part of the information-gathering 

process, OSHA hosted a stakeholder 

meeting on October 17, 2007. The 

meeting provided OSHA representatives 

and stakeholders an opportunity for 

informal discussion, open conversation, 

and the exchange of data, ideas, and 

points of view regarding occupational 

exposure to diacetyl and food flavorings 

containing diacetyl. The meeting 

addressed not only specific OSHA 

information requests, but also identified 

stakeholder concerns associated with 

developing a standard addressing 

occupational exposure to diacetyl and 

food flavorings containing diacetyl. A 

summary report of this stakeholder 

meeting is available in the docket and 

on OSHA’s Web page (OSHA, 2007a). 

OSHA has initiated a number of 

enforcement and compliance assistance 

activities. On July 27, 2007, the Agency 

announced a National Emphasis 

Program requiring inspections of all 

workplaces where butter flavored 

microwave popcorn is produced 

(OSHA, 2007b). OSHA has published a 

Safety and Health Information Bulletin 

that addresses respiratory disease 

among employees in microwave 

popcorn processing plants (OSHA, 

2007c). The Agency has also published 

a guidance document that addresses 

responsibilities of flavoring 

manufacturers and employers who must 

comply with OSHA’s Hazard 

Communication Standard with regard to 

diacetyl and food flavorings that contain 

diacetyl (OSHA, 2007d). 

In this notice, OSHA is seeking 

information to help the Agency resolve 

some of the issues discussed above. 

OSHA believes that its decisionmaking 

process will benefit from gathering 

public input on relevant studies and 

scientific information; data regarding 

the frequency, intensity, duration, and 

other parameters of employee exposure 

in the affected industries, occupations, 

and activities; key default factors and 

assumptions; and other relevant 

information related to the development 

of a health standard regulating 

occupational exposure to diacetyl and 

food flavorings containing diacetyl. 

B. Properties and Uses 

Flavorings containing diacetyl are in 

a variety of foods. Of particular note is 

the use of butter flavorings that contain 

diacetyl in microwave popcorn. Butter 

flavoring is mixed with oils and other 

ingredients and added to the bag during 

microwave popcorn production. Both 

natural and artificial butter-flavored 

popcorn may contain diacetyl. Diacetyl 

(C4H6O2, other names: butanedione or 

2,3-butanedione, CAS number 431–03– 

8) is an organic chemical that occurs 

naturally in dairy products, and is a 

natural byproduct of fermentation and 

brewing. It also is widely used in 

flavorings, particularly flavorings 

designed to provide a dairy, buttery, or 

ripe taste. In addition, diacetyl is used 

in some fragrances. 

Diacetyl can be produced several 

ways, including by extraction from 

dairy products, fermentation processes 

or chemical synthesis. Under Food and 

Drug Administration classifications, 

diacetyl produced by extraction from 

natural products is classified as a 

natural flavoring while diacetyl 

produced by other means is classified as 

an artificial flavoring. There is no 

difference in the chemistry of ‘‘natural’’ 

and ‘‘artificial’’ diacetyl. 

The Flavor and Extract Manufacturers 

Association (FEMA) estimates that each 

year the U.S. flavorings industry 

consumes approximately 228,000 

pounds of diacetyl, most of which is 

imported (FEMA, 2005). Flavoring 

manufacturers are largely firms that mix 

natural and artificial substances to 

create flavorings. OSHA has identified 

139 establishments, employing an 

estimated 8,972 employees, that 

produce flavorings containing diacetyl 

(ERG, 2007). 

The principal types of flavorings that 

use diacetyl are dairy flavors such as 

butter, cheese, sour cream, egg, or 

yogurt flavors; and the so-called ‘‘brown 

flavors’’ such as caramel, butterscotch, 

brown sugar, maple or coffee flavors. 

Some fruit flavors (e.g., strawberry and 

banana) may also contain diacetyl. 

There are also a variety of special uses 

of diacetyl such as in vanilla, tea, and 

other flavorings that are difficult to 

categorize broadly. 

Food flavorings containing diacetyl 

are used in a wide variety of products 

throughout the food processing sector. 

In addition to microwave popcorn, 

flavorings containing diacetyl are 

commonly used in the production of 

margarine and butter-flavored oils and 

cooking sprays, in retail and commercial 

bakeries, the production of some snack 

foods (particularly those with cheese 

flavoring), and in many confectionaries. 

Dairy, butter, and cheese flavors are 

sometimes used in frozen foods, canned 

foods, salad dressings, cheese and dairy 

substitutes, flavored wines and liquors, 

pet food, and specialty preparations. 

Fruit flavorings containing diacetyl are 

used in some yogurt and ice cream 

products. 

When food preparation facilities and 

restaurants heat food and other products 

containing butter-flavored margarines, 

oils, cooking sprays, and butter, food 

preparation employees may be exposed 

to diacetyl. Diacetyl is reported to be 

used in fragrances for some fruit scents 

and for some floral scents, such as 

geranium and magnolia. Diacetyl may in 

turn appear in some fragrance-using 

products such as scented candles (Lone 

Star, 2003). Diacetyl also has antibacterial properties and may be used as 

a preservative (Bibek, 2004). 

Flavorings, including butter flavoring, 

are complex mixtures and may contain 

volatile compounds, including other 

potential airway reactive substances. 

Apart from diacetyl, one of those 

substances is acetoin (C4H8O2, other 

names: 3-hydroxybutanone or acetyl 

methyl carbonol, CAS number 513–86– 

0). Acetoin is known to be used in 

butter flavorings and may be used in 

other flavorings, including flavorings in 

which diacetyl is used. Acetoin is 

structurally similar to diacetyl and 

shares common metabolic pathways 

with diacetyl. It has been found in the 

same workplace environments at 

concentrations approaching those of 

diacetyl. Like diacetyl, acetoin also 

occurs naturally in dairy products and 

has uses similar to diacetyl. Other 

volatile organic compounds found in 

some food flavorings include 

acetaldehyde, acetic acid, and furfural. 

Motivated by public concerns about 

possible health effects of diacetyl, some 

flavoring and food product 

manufacturers have begun or are 

planning to substitute other chemicals 

for diacetyl, since most flavorings can 


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1The most common pulmonary function tests, 

including FEV1 and FVC, are often measured using 

spirometry, which measures the flow of air in and 

out of the lungs. Forced expiratory volume—one 

second (FEV1) is the volume of air that a person can 

exhale through a mouthpiece in one second. Forced 

vital capacity (FVC) is the amojunt of air that can 

be exhaled following full inspiration. For accurate 

measurement of FVC, a person must inhale as 

deeply as possible and then exhale as forcefully as 

possible through a mouthpiece, for as long as 

posssible. 

2NIOSH subsequently determined that the 

diacetyl sampling method used in its investigations 

of microwave popcorn and flavor manufacturing 

facilities can be affected by relative humidity and 

that high humidity levels may result in an 

underestimation of true airborne diacetyl 

concentrations (NIOSH, 2003b). NOISH is working 

to develop a set of correction factors and to validate 

a new method for the measurement of diacetyl in 

the workplace. 

be made without diacetyl. For example, 

many microwave popcorn producers 

have substituted or are seeking to 

substitute alternatives to diacetyl in 

butter flavoring (ConAgra, 2007; Pop 

Weaver, 2008). OSHA has noted three 

substances promoted as diacetyl 

substitutes—acetoin, diacetyl trimer 

(OSHA, 2007a), and a sulfite adduct of 

diacetyl (Turin, 2007). Both diacetyl 

trimer and the sulfite adduct of diacetyl 

have a low vapor pressure in their basic 

form, and are thus less likely to 

evaporate and result in employee 

inhalation exposures during the 

production process. However, both are 

converted to diacetyl during consumer 

food preparation, so that the foods when 

consumed will contain diacetyl. For 

example, if placed on popcorn, both 

convert to diacetyl when the popcorn is 

popped. 

C. Health Effects Studies of Exposure to 

Butter Flavorings and Diacetyl 

A number of studies, including 

several occupational investigations and 

case reports, have documented 

obstructive airway disease among 

employees exposed to airborne butter 

flavoring chemicals (Kanwal et al., 

2008). While cases of obstructive lung 

disease had been described among 

employees at flavoring manufacturing 

sites in a few earlier reports, the 

scientific community did not become 

aware of flavoring-related obstructive 

airway disease until 2000 after a case 

cluster was identified at a microwave 

popcorn production plant. Subsequent 

investigations at microwave popcorn 

production plants demonstrated higher 

rates of respiratory symptoms such as 

chronic cough, shortness of breath, and 

wheezing among employees engaged in 

certain job activities when compared to 

the rates expected among the U.S. 

population adjusted for age and 

smoking status. In some cases, these 

effects may be symptomatic of a 

potentially disabling obstructive lung 

disease known as constrictive 

bronchiolitis obliterans. Higher-thanexpected rates of physician-diagnosed 

asthma and chronic bronchitis have also 

been reported. Some employees exposed 

to butter flavoring have also 

experienced eye, skin, nose, and throat 

irritation. 

Spirometry surveys in the 

investigations of microwave popcorn 

production plants revealed higher 

prevalences of airway obstruction, 

defined as a reduction in FEV1 and 

FEV1/FVC ratio,1 than expected based 

on the adjusted rates among the U.S. 

population. Airway obstruction is 

described as fixed when abnormal 

pulmonary function test results do not 

improve with bronchodilator treatment. 

The onset of symptoms associated with 

fixed airway obstruction has been 

reported to occur after a few months to 

several years of exposure to butter 

flavorings that contained diacetyl in a 

microwave popcorn production facility 

(Akpinar-Elci et al., 2004). 

Fixed airway obstruction is 

characteristic of bronchiolitis obliterans. 

This lung disease results from 

inflammation and scarring of the tissue 

lining the small airways of the lung. In 

response to the damage, the airways 

become thickened, narrowed, and 

sometimes completely obstructed, 

limiting movement of air into and out of 

the lung. Because it is an uncommon 

condition, bronchiolitis obliterans may 

be misdiagnosed as the more frequently 

encountered obstructive lung diseases of 

chronic bronchitis, emphysema, or 

asthma. A high resolution computerized 

tomography (CT) scan or, sometimes, a 

specialized lung biopsy is needed to 

confirm a diagnosis of bronchiolitis 

obliterans. As airways become more 

severely damaged, employees with 

bronchiolitis obliterans suffer persistent 

symptoms and permanent loss of 

pulmonary function. Several employees 

with severe disease are on waiting lists 

to receive lung transplants. At least 

three employee deaths have been 

attributed to flavoring-related 

bronchiolitis obliterans (Egilman et al., 

2007). 

Investigations of Microwave Popcorn 

Plants 

The respiratory hazards associated 

with butter flavoring came under 

scrutiny with the diagnosis of 

bronchiolitis obliterans in eight former 

employees who had worked in mixing 

and packaging operations at a Missouri 

microwave popcorn plant (Parmet et al., 

2002). The National Institute of 

Occupational Safety and Health 

(NIOSH) evaluated the medical 

condition of current employees at the 

plant (Kreiss et al., 2002). The 

prevalence of airway obstruction was 

3.3 times higher than expected for all 

employees and 10.8 times higher than 

expected for employees who had never 

smoked based on national statistics. The 

frequency and extent of the airway 

obstruction was greatest among mixing 

room and packaging area employees 

with the highest exposures to the butter 

flavoring vapors. Medical symptoms 

that were elevated among production 

workers included chronic cough, 

shortness of breath upon exertion, 

wheezing, physician diagnosed asthma 

and chronic bronchitis, unusual fatigue, 

and skin and mucous membrane 

irritation. Rates of physician-diagnosed 

asthma and chronic bronchitis were also 

higher than expected based on national 

statistics. NIOSH noted that five of six 

current employees who worked in the 

quality control room popping nearly 100 

bags of product in microwave ovens per 

shift suffered airway obstruction despite 

relatively low full shift exposure to 

butter flavoring vapors. 

NIOSH then investigated five 

additional microwave popcorn plants 

which confirmed and extended its 

initial findings (Kanwal et al., 2006). 

The prevalence of airways obstruction 

and respiratory symptoms was highest 

among flavorings mixers with longer 

work histories and packaging operators 

who worked in close proximity to 

mixing tanks of oil and flavorings. Six 

employees currently engaged in these 

job operations at four microwave 

popcorn plants were found to have 

clinical evidence consistent with 

bronchiolitis obliterans. Production and 

non-production employees with the 

least exposure to butter flavoring 

chemicals had the lowest rates of airway 

disease and respiratory symptoms. 

As an indicator of exposure to butter 

flavoring vapors, NIOSH measured full 

shift area and personal time-weighted 

average (TWA) air concentrations of 

diacetyl in several job locations of the 

six investigated plants (Kanwal et al., 

2006). The average full shift air levels of 

diacetyl in the mixing areas and 

production locations in close proximity 

to mixing tanks ranged from 0.2 to 38 

ppm.2 By contrast, average diacetyl 

concentrations were 0.03 ppm or less in 

the packaging areas that were isolated 

from the mixing tanks. Several taskbased measurements at one plant 

showed that diacetyl concentrations 

averaged 5 to 10 ppm for 30 to 60 

minutes following the open transfer of 


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butter flavoring to heated mixing tanks 

(NIOSH, 2003a). 

Investigations of Plants That 

Manufacture Food Flavors That Contain 

Diacetyl 

Cases of airway obstruction have also 

been reported and investigated in food 

flavor manufacturing facilities. NIOSH 

described severe fixed airway 

obstruction compatible with 

bronchiolitis obliterans in two former 

employees of a company that blended 

large batches of flavoring ingredients 

with corn starch and flour to make 

‘‘cinnabutter’’ and other flavors for use 

in the baking industry (NIOSH, 1986). 

Researchers at the University of 

Cincinnati College of Medicine reported 

severe respiratory disease with clinical 

findings consistent with bronchiolitis 

obliterans in five employees at a large 

flavor manufacturing facility (Lockey et 

al., 2002). The State of California began 

an active investigation of obstructive 

airway disease at flavoring 

manufacturing establishments in the 

State after learning of two employees 

with confirmed bronchiolitis obliterans 

at separate Southern California plants 

(CDC, 2007). By January 2007, the State 

identified six additional employees with 

suspected fixed obstructive lung disease 

at three additional flavor manufacturing 

establishments (Materna, 2007). The 

eight individuals were flavoring 

compounders and their jobs involved 

mixing chemicals, including diacetyl, to 

make food flavorings. 

Recently, NIOSH conducted health 

hazard evaluations at two Southern 

California flavor manufacturing plants 

(NIOSH, 2007a; 2007b) where four 

current or former employees who 

worked in powder production and 

handled diacetyl or diacetyl-containing 

flavors had severe fixed airway 

obstruction. Personal air sampling 

completed at one plant found mean fullshift TWA diacetyl air levels of 0.22 

ppm (range: 0.002 ppm to 1.1 ppm) and 

mean process-associated diacetyl air 

levels of 7.7 to 21 ppm over one to two 

hour productions of diacetyl-containing 

butter-flavored and vanilla-flavored 

powders.2

A study by the National Jewish 

Medical and Research Center (NJMRC) 

found that production employees from 

eleven flavoring manufacturing sites 

reported higher than expected rates of 

respiratory symptoms and asthma (Rose, 

2007). The study also found that 

employees with the highest cumulative 

exposures to diacetyl were more likely 

to experience process-related breathing 

problems and eye, nose, and throat 

irritation than employees with the 

lowest cumulative exposures. The 

highest diacetyl air levels were 

measured during the production of 

powder and liquid formulations using 

the NIOSH sampling method 2 (Martyny 

et al., 2008). 

Workplace air levels of diacetyl in 

powder production areas of monitored 

plants as well as the type of respiratory 

problems experienced by the employees 

were similar to those found in the 

mixing areas of microwave popcorn 

plants. However, one important 

distinction is that employees who work 

in mixing operations at microwave 

popcorn plants are typically exposed to 

butter flavorings on a daily basis while 

flavoring compounders are usually 

exposed less frequently at some flavor 

manufacturing facilities. Thus, based on 

currently available information, it is not 

clear whether the risk of airway 

obstruction among blenders working at 

food flavoring manufacturing would be 

similar to mixers in microwave popcorn 

production. 

Investigation at a Diacetyl Production 

Plant 

Four cases of obstructive airway 

disease compatible with bronchiolitis 

obliterans were found among diacetyl 

process operators who worked at a 

Dutch chemical plant that produced 

diacetyl (Van Rooy et al., 2007). These 

workers were regularly exposed to 

diacetyl and a limited number of other 

agents, as opposed to the much larger 

number of compounds present during 

flavor manufacture or use of butter 

flavoring in microwave popcorn 

production. In addition to diacetyl, 

acetoin was manufactured as a coproduct during the diacetyl production 

process. Acetaldehyde and acetic acid 

were also formed as side products 

during the process. The employees in 

the study reported a greater prevalence 

of certain respiratory symptoms, such as 

trouble breathing, chronic cough, and 

physician-diagnosed asthma than the 

general Dutch population when 

adjusted for age and smoking habits 

(Van Rooy et al., 2008). 

Inhalation Studies in Experimental 

Animals 

NIOSH examined the effects of liquid 

butter flavoring vapors (BFV) and pure 

diacetyl on the respiratory tract of 

Sprague Dawley rats exposed to a onetime six hour inhalation study (Hubbs et 

al., 2002; 2008). Rats exposed to 

diacetyl above 200 ppm either as pure 

vapor or as a mixture with other butter 

flavoring compounds suffered dosedependant inflammation and necrosis of 

the epithelium extending from the nose 

into the bronchii. The epithelial injury 

in rats exposed to pure diacetyl covered 

a less extensive area of the respiratory 

tract than BFV-exposed animals 

receiving similar diacetyl 

concentrations. This suggests that other 

butter flavoring components in addition 

to diacetyl may contribute to the 

flavoring-induced airway damage. There 

also was no difference in respiratory 

damage whether the total diacetyl dose 

was administered continuously over six 

hours or in four 15 minute pulses. There 

were no significant pathological changes 

in bronchiolar epithelium or alveoli at 

any diacetyl concentration. 

A National Institute of Environmental 

Health Sciences (NIEHS) study found 

respiratory effects in mice exposed to 

pure diacetyl. NIEHS evaluated the 

respiratory tract toxicity in C57BL/6 

mice exposed to repeated inhalations of 

pure diacetyl for up to twelve weeks 

(Morgan et al., 2008). Mice exposed to 

50 ppm and 100 ppm dose levels were 

found to have dose-dependant mild to 

moderate nasal tissue necrosis. A 

lymphocytic bronchitis extending into 

the lower airways was found in the mice 

exposed to 100 ppm. In an effort to 

bypass the extensive removal of watersoluble diacetyl vapors that occurs in 

the nasal passages of mice, liquid 

diacetyl was forced deep into the lung 

by oropharyngeal aspiration. This 

caused fibrotic focii in the terminal 

bronchioles and alveolar ducts. 

Although these lesions were not 

identical to bronchiolitis obliterans, 

there was sufficient similarity to suspect 

that they may progress to bronchiolitis 

with continued exposure. The National 

Toxicology Program has approved the 

nomination of BFV, diacetyl, and 

acetoin for longer term inhalation 

testing. 

II. Request for Data, Information, and 

Comment 

OSHA is seeking data, information, 

and comment on a variety of topics 

relevant to the Agency’s development of 

a proposed rule addressing occupational 

exposure to diacetyl and food flavorings 

containing diacetyl. The questions 

below highlight specific areas of 

concern to OSHA. When answering 

specific numbered questions below, 

please key your responses to the number 

of the question, explain the reasons 

supporting your views, and identify and 

provide relevant information on which 

you rely, including any studies or 

articles that support your comments. In 

addition to the questions presented 

below, respondents are encouraged to 

address any aspect of occupational 

exposure to diacetyl and food flavorings 

containing diacetyl that they feel is 

pertinent. 


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When requesting information, OSHA 

refers to ‘‘diacetyl and food flavorings 

containing diacetyl.’’ In addition to food 

flavorings, OSHA intends the term to 

encompass diacetyl present in 

substances other than food flavorings 

(e.g., naturally occurring diacetyl or 

diacetyl in fragrances), as well as other 

constituents of food flavorings 

containing diacetyl. ‘‘Starter distillate,’’ 

also referred to as ‘‘butter starter 

distillate,’’ should be considered a form 

of diacetyl. 

As discussed previously, butter 

flavorings are complex and variable 

mixtures, containing a number of 

respiratory irritants and potential 

airway reactive substances. In addition 

to information on diacetyl, OSHA seeks 

information on acetoin, acetaldehyde, 

acetic acid, furfural, and other 

compounds present in food flavorings 

that may cause or contribute to 

flavoring-related lung disease. The 

Agency is also interested in information 

on substitutes used in place of diacetyl 

(e.g., diacetyl trimer). 

A. Production and Uses 

Diacetyl and food flavorings 

containing diacetyl are used in a wide 

variety of industries and processes, and 

employee exposure to these substances 

occurs in many different occupational 

settings. Exposures have been recorded 

in various operations in the microwave 

popcorn and the flavor manufacturing 

industries. Exposures are also likely in 

a wide range of food processing and 

food service industries where diacetyl 

and food flavorings containing diacetyl 

are used and in other industries where 

diacetyl is volatilized (e.g., fragrancerelated exposures). OSHA would 

appreciate detailed responses to these 

questions concerning the production 

and use of diacetyl and food flavorings 

containing diacetyl. 

1. What is your primary line of 

business? Please indicate the types of 

products or services your firm produces 

or provides, the number of 

establishments you have, and how many 

full-time and part-time employees work 

at each establishment. 

2. Does your firm or any other U.S. 

firm produce diacetyl? If so, indicate the 

form of diacetyl (e.g., powder, liquid, 

encapsulated) and the quantity 

produced, how frequently it is 

produced, and the circumstances in 

which it is produced. 

3. Does your firm use diacetyl? If so, 

indicate the form of diacetyl (e.g., 

powder, liquid, encapsulated) and 

quantity used, the purpose(s) it is used 

for, how frequently it is used, and the 

circumstances in which it is used. 

OSHA is particularly interested in the 

extent of diacetyl use as a preservative. 

Does your firm use diacetyl for that 

purpose? If so, please describe the 

nature of the use, the total volume of 

diacetyl used and potential employee 

exposure. 

4. Does your firm use any natural or 

artificial flavorings that might contain 

diacetyl, such as dairy (e.g., butter, 

cheese, sour cream, yogurt), ‘‘brown’’ 

(e.g., caramel, butterscotch, brown 

sugar, maple, coffee flavors), fruit, 

marshmallow, or egg flavorings? If so, 

please indicate which flavorings you 

use, the quantity you use, and the 

purpose(s) for their use. If any of these 

flavorings are known to contain 

diacetyl, please indicate which 

flavorings contain diacetyl and the 

percentage of diacetyl, by weight, they 

contain. 

5. Does your firm heat margarine or 

use butter-flavored cooking oils or 

cooking sprays? If so, please indicate the 

quantity of these substances you use 

and the purpose(s) for their use. If any 

of these substances are known to 

contain diacetyl, please indicate which 

substances contain diacetyl and the 

percentage of diacetyl, by weight, they 

contain. 

6. Does your firm use, add, or handle 

flavorings or food products that contain 

naturally occurring diacetyl, such as 

dairy products, wine or beer? Please 

describe the circumstances in which 

you use, add, or handle naturally 

occurring diacetyl. 

7. Does your firm manufacture or use 

fragrances? If so, do any of these 

fragrances contain diacetyl? Please 

indicate which fragrances contain 

diacetyl, how much diacetyl they 

contain, how the fragrances are used, 

and the quantities produced or used. 

B. Employee Exposure 

8. What are the job categories and 

operations in which employees are 

potentially exposed to diacetyl or food 

flavorings containing diacetyl in your 

company or industry? For each job 

category or operation, please provide a 

description of how the exposure takes 

place. OSHA is particularly interested 

in any operations that involve manual 

tasks; operations that involve products 

being sprayed, sprinkled, or coated with 

flavorings or ingredients containing 

diacetyl; operations that involve heating 

of ingredients; and tasks in laboratories 

for product testing or research and 

development that involve handling of 

diacetyl or food flavorings containing 

diacetyl. 

9. How many employees are exposed 

to diacetyl or food flavorings containing 

diacetyl, or have the potential for 

exposure, in each job category or 

operation in your company or industry? 

10. What are the frequency, duration, 

and levels of employee exposures to 

diacetyl in each job category in your 

company or industry? Please indicate 

the engineering or other controls in 

place when exposures were measured, 

as well as the analytical method and 

type of samples used for determining 

exposure levels. If possible, OSHA 

requests that you provide personal 

exposure sampling data with clear 

descriptions of the length of time the 

samples were collected. If personal 

sampling data are not available, OSHA 

requests any exposure data you provide 

indicate the form and length of the 

exposure. If sampling was performed 

using NIOSH Method 2557, please 

indicate the flow rate used and the 

temperature and relative humidity at the 

time sampling was performed, if 

possible. 

11. How many years do employees 

potentially exposed to diacetyl or food 

flavorings containing diacetyl remain in 

their jobs? Do employees who leave 

such positions typically move to new 

jobs that do not involve exposure, or are 

they likely to transfer to jobs that 

involve potential exposure to diacetyl or 

food flavorings containing diacetyl? 

C. Health Effects 

The Background section discusses 

several studies that report an increased 

occurrence of airway obstruction, 

bronchiolitis obliterans, and other 

respiratory disorders among employees 

in jobs involving exposure to diacetyl 

and food flavorings containing diacetyl. 

Diacetyl and other potential airway 

reactive compounds (e.g., acetoin, 

acetaldehyde, acetic acid, furfural) 

present in food flavorings may 

contribute to the observed respiratory 

effects. The Agency is seeking 

additional studies, articles, data, and 

information that OSHA can use to 

evaluate health effects related to 

occupational exposure to these 

substances. The Agency specifically 

requests the following: 

12. Describe and provide any 

additional case reports, epidemiological 

and animal studies, and data not 

mentioned in this notice that OSHA 

should consider in evaluating the 

potential health risks associated with 

exposure to diacetyl and food flavorings 

containing diacetyl. If available, please 

include associated short-term, taskoriented, and full-shift time weighted 

average exposure data and indicate the 

method of sampling and analysis used. 

If sampling was performed using NIOSH 

Method 2557, please indicate the flow 

rate used and the temperature and 


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relative humidity at the time sampling 

was performed. Describe and provide 

any studies and data that report changes 

in the occurrence of flavoring-related 

health risks from implementing 

exposure controls and work practices. 

13. Describe and provide any 

available reports and data, not 

mentioned in this notice, on employees 

experiencing respiratory symptoms, 

pulmonary function abnormalities, 

clinical evidence of respiratory disease, 

or other adverse health outcomes 

associated with exposure to diacetyl or 

food flavorings containing diacetyl at 

your establishment or other 

establishments where these substances 

are manufactured or used. Please 

include information on the nature of the 

use, processes, job tasks, and exposures. 

14. Describe any ongoing efforts to 

collect information and data that would 

assist in the identification of adverse 

health effects associated with diacetyl 

and food flavorings containing diacetyl. 

Please provide any currently available 

reporting information, anticipated date 

of completion and when the completed 

research report and/or data collection 

could be made available to OSHA for 

the development of a proposed rule. 

15. Occupational investigations have 

reported respiratory symptoms and 

spirometry abnormalities, particularly 

reduced FEV1 and FEV1/FVC, among 

employees in jobs involving exposure to 

diacetyl and food flavorings containing 

diacetyl. What respiratory 

symptomatology and declines in these 

spirometry test values should OSHA 

consider to be indicative of flavoringrelated respiratory disease? Please 

identify the prevalence of symptoms 

and other clinical findings associated 

with various levels of reduction in FEV1

and FEV1/FVC. Please cite your sources. 

16. Where longitudinal information is 

available, please describe any 

progression of symptoms, pulmonary 

function test results, and other clinical 

findings or abnormalities that may have 

preceded cases of bronchiolitis 

obliterans. 

17. Is there any evidence that other 

potential airway-reactive flavoring 

compounds, such as those mentioned in 

the lead paragraph of this section, 

contribute to flavoring-related 

respiratory disease? Are there structure 

activity data that may be useful for 

predicting compounds likely to cause 

airway damage? Please explain and 

provide supporting data. 

18. Describe and provide any studies 

and data related to respiratory tract 

absorption, clearance, and metabolism 

of diacetyl or other flavoring agents that 

may be likely to contribute to flavoringrelated respiratory disease. Describe and 

provide studies and data pertinent to 

understanding the mechanism of action 

by which these compounds may cause 

adverse respiratory system effects. 

19. Research studies report that 

diacetyl preferentially damages the 

lining of the nose and upper respiratory 

tract when inhaled by rats and mice. 

Should OSHA consider the upper 

airway damage in experimental animals 

exposed to diacetyl or butter flavoring 

vapors as clinically relevant to the 

respiratory disease that occurs in the 

lower airways of employees exposed to 

food flavorings containing diacetyl? 

Please explain. Are there other 

examples of toxic agents that damage 

the nose and upper airways when 

inhaled by rodents but cause primarily 

lower airway disease in humans? Please 

support your response with specific 

examples and studies. 

D. Risk Assessment 

OSHA is interested in data that will 

assist the Agency in developing 

quantitative estimates of any 

occupational risk of airway obstruction, 

fixed airways obstruction, bronchiolitis 

obliterans, and any other relevant 

biological endpoints from exposures to 

diacetyl and food flavorings containing 

diacetyl. 

20. What biological endpoints should 

OSHA consider to estimate the 

occupational risk to employees exposed 

to diacetyl or food flavorings containing 

diacetyl? Are there endpoints other than 

airway obstruction, fixed airway 

obstruction, and bronchiolitis obliterans 

that OSHA should consider? Please 

explain. 

21. What studies or data should be 

used to derive a quantitative estimate of 

the risk resulting from exposure to 

diacetyl or food flavorings containing 

diacetyl? OSHA seeks studies, scientific 

information, and data regarding 

frequency, intensity, duration, and other 

parameters of worker exposure in the 

affected industries, occupations, and 

activities; key default factors and 

assumptions; and other relevant 

information related to the potential 

development of a health standard 

regulating diacetyl and food flavorings 

containing diacetyl. 

22. In its risk assessment, how should 

the Agency treat cross-sectional data 

describing the prevalence of airway 

obstruction? Please describe the 

relationship that might be expected, in 

an occupational setting, between the 

prevalence and incidence of airway 

obstruction. 

23. In studies investigating employees 

exposed to diacetyl or food flavorings 

containing diacetyl, what proportion, if 

any, of employees who experienced 

airway obstruction in those studies 

might be expected to develop 

bronchiolitis obliterans? Please explain 

your reasoning. 

24. When developing dose-response 

assessments from animal studies, what 

adjustments and/or scaling factors 

should OSHA consider to account for 

species differences between animals and 

humans in the dose delivered to the 

lower respiratory tract? Are there 

toxicokinetic models that can assist in 

these interspecies extrapolations? Please 

explain. 

25. Some of the job categories 

associated with higher-than-expected 

prevalences of airway obstruction 

involved tasks that generated very high 

short-term peak exposures to food 

flavorings containing diacetyl. What 

role may short-term and cumulative 

exposures to diacetyl or food flavorings 

containing diacetyl play in causing 

health effects and how should OSHA 

account for this in the risk assessment? 

26. What exposure metric(s) (e.g., 

cumulative exposure, duration of 

exposure, and short-term task-based 

exposure) should OSHA consider in 

assessing the risk associated with 

exposure to diacetyl or food flavorings 

containing diacetyl? Are means, 

geometric means, or medians preferable 

as measures of central tendency of 

group exposure data? 

27. What statistical methods, models, 

and data should OSHA consider for 

estimating the risk from exposure to 

diacetyl and food flavorings containing 

diacetyl? 

28. What job classifications, tasks, or 

operations involving diacetyl or food 

flavorings containing diacetyl may be 

associated with an elevated occurrence 

of adverse health effects? For example, 

some studies have reported higher-thanexpected prevalences of airway 

obstruction in employees performing 

mixing and quality control tasks. 

29. Please describe and provide any 

studies or data you believe the Agency 

should consider regarding doseresponse behavior and mode of action of 

diacetyl including physiochemical, 

metabolic, cellular, mechanistic, and 

dosimetric considerations. For instance, 

are adverse health effects dependent on 

the dose rate and intensity over the 

exposure period rather than the total 

cumulative dose received? Please 

explain. Do the data and mode of action 

suggest a threshold effect? Please 

explain. 

30. Does the form of diacetyl (e.g., 

liquid vs. powdered) affect doseresponse behavior? For example, does 

the form of diacetyl affect its respiratory 

deposition? If so, please explain. 


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31. Are there any existing risk 

assessments addressing diacetyl or food 

flavorings containing diacetyl that 

OSHA should consider? Please identify 

and provide. 

E. Exposure Assessment and Monitoring 

Methods 

32. Do you conduct exposure 

monitoring for diacetyl or other 

chemicals (e.g., acetoin, acetaldehyde, 

acetic acid, furfural) found in food 

flavorings? If so, please indicate the 

chemical(s) sampled for; the method(s) 

of sampling and analysis used; the type 

of samples collected (i.e., personal or 

area samples); the job categories, tasks, 

operations, or areas where sampling is 

performed; the duration of sampling 

(e.g., 8-hour time-weighted average, 15 

minute peak); and the frequency of 

sampling. 

33. What type of sampling methods 

are available for measuring diacetyl in 

the workplace when it is encapsulated 

within a powder matrix or adsorbed 

onto a powder surface? Please provide 

information on any sampling and 

analytical methods applicable for 

determining exposure to diacetylcontaining powders based on total, 

respirable, thoracic, or inhalable size 

fractions. Are there any methods under 

development or any laboratory methods 

used by food flavorists or food chemists 

that could potentially be applied? Please 

provide any information available on 

the precision and accuracy of the 

sampling method, the range and limits 

of detection, and the method of 

validation of sampling and analysis. 

Please also provide methods for analysis 

of diacetyl in bulk process materials. 

34. If sampling is conducted by inhouse staff to evaluate employee 

exposure to diacetyl and food flavorings 

containing diacetyl, please indicate the 

number of hours required to collect the 

samples and costs for laboratory 

analysis. If you engage an outside party 

to perform sampling and analysis, 

please indicate the costs incurred. 

F. Control Measures 

35. To what extent have you or other 

users reduced or eliminated use of 

diacetyl or food flavorings containing 

diacetyl? Please explain how you have 

achieved those reductions. What 

substitutes are used for diacetyl? What 

types of flavorings have been most 

affected by reduction or elimination of 

diacetyl use? What types of flavorings 

are most suitable for change and what 

types are most difficult to produce 

without diacetyl? What factors have 

been responsible for changes in diacetyl 

use (e.g., employee health concerns, 

consumer demand)? If you have not 

reduced or eliminated the use of 

diacetyl, what were your reasons for not 

substituting at this time? OSHA requests 

that commenters indicate why 

substitutes for diacetyl have or have not 

been used, and describe any 

technological, economic or other 

barriers or hindrances to substitution. 

OSHA also requests measurements of 

employee exposure to substances used 

as substitutes for diacetyl, and any 

measurements of employee exposure to 

diacetyl after substitution, particularly 

for substitutes which may convert to 

diacetyl. 

36. Have you installed engineering 

controls or adopted work practices to 

reduce exposures to diacetyl and food 

flavorings containing diacetyl? If so, 

please indicate the types of controls 

implemented and the operations, tasks, 

or processes where they have been 

applied. Please describe whether and to 

what extent these controls have reduced 

employee exposure. Please indicate any 

operations or processes in your facility 

for which engineering controls are not 

available or have not been applied. 

Please explain what difficulties you 

have encountered in applying 

engineering controls in those 

operations. 

37. Does your firm limit access to 

areas where diacetyl or food flavorings 

containing diacetyl are present in order 

to control employee exposures to these 

substances? Please describe the basis for 

establishing these areas (e.g., operations, 

exposure levels), methods used to 

demarcate and control access to the 

areas, and any obstacles to 

implementation. 

38. Do you provide respirators or 

other types of personal protective 

equipment (e.g., gloves) to employees 

exposed to diacetyl or food flavorings 

containing diacetyl? If so, describe your 

program and identify the type of 

equipment provided, the basis for 

selection, and any difficulties 

encountered in implementing your 

program. 

39. Describe the conditions in which 

respirators and other personal protective 

equipment are used, including any 

criteria (e.g., regulated area, exposure 

level, type of operation, duration of 

exposure) you use for triggering their 

use. Are there any processes or areas 

where it is not possible to use 

respirators or other protective 

equipment? Please explain. 

G. Employee Training 

40. What information and training do 

you provide to your employees about 

occupational exposure to diacetyl and 

food flavorings containing diacetyl? 

Please describe your training program, 

including job categories included in the 

program, criteria for determining which 

employees receive information and 

training, program content, methods of 

providing information and training, 

length of training, frequency, and any 

procedures used to address language or 

literacy barriers. 

41. How do you determine the 

effectiveness of training? Describe 

methods used and any factors taken into 

account in examining the effectiveness 

of training programs. 

H. Medical Surveillance Programs 

OSHA is interested in medical 

surveillance programs that employers 

use or recommend to identify and 

monitor employees who exhibit signs, 

symptoms, or other clinical findings 

associated with occupational exposure 

to diacetyl and food flavorings 

containing diacetyl. 

42. Do you have a medical 

surveillance program to identify or 

prevent health effects associated with 

exposure to diacetyl and food flavorings 

containing diacetyl (this could include 

a general medical surveillance program 

that would cover exposure to other 

chemicals)? Please describe your 

program. What tests, procedures, 

examinations, and questions does your 

program include and at what frequency? 

Please provide any protocols and 

standards of care. What are the 

qualifications and credentials of the 

health professionals supervising and 

administering the surveillance program? 

43. What criteria (e.g., job categories, 

duties, exposure levels) do you use or 

recommend to determine when to 

provide medical screening or 

surveillance? 

44. What signs, symptoms, test 

results, or illnesses have been detected 

or reported that you believe may be 

related to exposure to diacetyl or food 

flavorings containing diacetyl? What 

jobs, tasks, and operations did affected 

employees perform? What levels of 

diacetyl were affected employees 

exposed to (including 8-hour timeweighted averages during an 8-hour 

work shift and during specific tasks, 15 

minute peaks, cumulative exposure, and 

the duration of exposure, if available)? 

45. Have any of your employees been 

diagnosed with bronchiolitis obliterans? 

If so, please describe any pulmonary 

function abnormalities or other clinical 

signs or symptoms that preceded the 

diagnosis. 

46. If your medical surveillance 

program includes pulmonary function 

testing, please describe any crosssectional findings or longitudinal trends 

that you have observed. Specifically, 

what correlations, if any, have you 


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observed between pulmonary function 

test results and exposure to diacetyl or 

food flavorings containing diacetyl 

(including associations with peak 

exposures, cumulative exposure, 

duration of exposure, or particular job 

classifications, tasks, or operations)? 

Please describe whether and how 

findings or trends have varied 

depending on the form of diacetyl to 

which employees have been exposed 

(e.g., powdered vs. liquid formulation). 

47. Have you ever removed employees 

from a job because of adverse health 

effects attributed to exposure to diacetyl 

or food flavorings containing diacetyl? If 

so, please describe the circumstances of 

the removal, what jobs they were moved 

into, and potential return. For how long 

were these employees generally 

removed? Have any employees ever 

been permanently removed from a job 

because of such adverse health effects? 

48. Have medical screening and 

surveillance had any effect on the 

number and severity of adverse health 

effects detected or reported? 

49. Please describe the costs of 

medical surveillance for employees 

exposed to diacetyl and food flavorings 

containing diacetyl. Where possible, 

please indicate the number of hours per 

year the average employee spends on 

activities related to medical surveillance 

or screening and how many of those 

hours are spent traveling to see health 

care providers. If you employ a health 

care provider to administer medical 

surveillance programs, please indicate 

the number of hours the health care 

provider spends each year on screening, 

surveillance and management of 

employees exposed to diacetyl or food 

flavorings containing diacetyl. If you do 

not employ a health care provider to 

administer medical programs, please 

indicate the costs per employee for 

surveillance or screening for adverse 

health effects associated with diacetyl or 

food flavorings containing diacetyl. 

Also, please describe the cost of any 

equipment or supplies that you have 

purchased for use in medical programs 

associated with exposure to diacetyl or 

food flavorings containing diacetyl. 

I. Environmental Impacts 

The National Environmental Policy 

Act (NEPA) of 1969 (42 U.S.C. 4321, et 

seq.), the Council on Environmental 

Quality (CEQ) regulations (40 CFR part 

1500), and the Department of Labor 

(DOL) NEPA Compliance Regulations 

(29 CFR part 11), require that OSHA 

give appropriate consideration to 

environmental issues and the impacts of 

proposed actions that significantly affect 

the quality of the human environment. 

OSHA is currently collecting written 

information and data on possible 

environmental impacts that could occur 

outside of the workplace (e.g., exposure 

to the community through contaminated 

air/water, contaminated waste sites) if 

the Agency were to promulgate a 

standard for occupational exposure to 

diacetyl and food flavorings containing 

diacetyl. Such information should 

include both negative and positive 

environmental effects that could be 

expected to result from a revised 

standard on occupational exposure to 

diacetyl or food flavorings containing 

diacetyl. Specifically, OSHA requests 

comments and information on the 

following: 

50. What is the potential direct or 

indirect environmental impact (for 

example, the effect on air and water 

quality, energy usage, solid waste 

disposal, and land use) that might result 

from a reduction in employee exposure 

to diacetyl or food flavorings containing 

diacetyl or the use of substitutes for 

diacetyl or food flavorings containing 

diacetyl? 

51. Are there any situations in which 

reducing exposures of diacetyl or food 

flavorings containing diacetyl to 

employees would be inconsistent with 

meeting environmental regulations? 

(Note: In estimates of control costs, 

OSHA will account for any costs of 

meeting air quality requirements 

associated with increased ventilation 

controls. The issue here is whether there 

are situations in which ventilation and 

other controls would be incompatible 

with air pollution controls.) 

J. Economic Impacts 

52. What do you estimate would be 

the expected costs of a standard to 

control occupational exposure to 

diacetyl and food flavorings containing 

diacetyl? What do you estimate would 

be the costs for enhanced ventilation 

controls in your establishments? What 

do you estimate would be the costs of 

providing exposure assessments, 

medical surveillance and training? 

Please explain how you derived your 

cost estimates. 

53. What are the potential economic 

impacts associated with a standard to 

control occupational exposure to 

diacetyl and food flavorings containing 

diacetyl? Will the expected costs have a 

severe impact on your firm or your 

industry? Please explain. Please indicate 

what industry segment you represent. 

Do you anticipate any difficulties in 

providing exposure assessments, 

medical surveillance, or training? Please 

explain. 

54. Are there foreign sources of food 

flavorings containing diacetyl? What are 

those sources? 

55. In response to a standard on 

occupational exposure to diacetyl or 

food flavorings containing diacetyl, will 

firms stop manufacturing or using food 

flavorings containing diacetyl, or will 

they implement controls to reduce 

potential exposures? Can you estimate 

the share of flavoring manufacturers that 

will eliminate food flavorings 

containing diacetyl and the share that 

will continue to manufacture them? 

What substances are available now, or 

might be available in the future, as 

substitutes for diacetyl or food 

flavorings containing diacetyl? What 

would be the costs and economic 

impacts associated with substituting 

other flavoring ingredients for diacetyl? 

K. Impacts on Small Entities 

The Regulatory Flexibility Act 

requires that OSHA assess the impact of 

proposed and final rules on small 

entities (5 U.S.C. 601 et seq.). OSHA 

requests that members of the small 

business community and others familiar 

with small business concerns address 

any special circumstances small entities 

might face in controlling occupational 

exposure to diacetyl and food flavorings 

containing diacetyl. OSHA has already 

determined that this regulatory action 

will require a preliminary regulatory 

flexibility analysis, and thus a Small 

Business Regulatory Enforcement 

Fairness Act panel (5 U.S.C. 609(b)). 

56. How many and what kinds of 

small entities perform operations using 

diacetyl or food flavorings containing 

diacetyl? What percentage of the 

affected industries do they comprise? 

57. How and to what extent would 

small entities in your industry be 

affected by the promulgation of a 

standard that addresses occupational 

exposure to diacetyl and food flavorings 

containing diacetyl? Are there special 

circumstances that make the control of 

occupational exposure to diacetyl and 

food flavorings containing diacetyl more 

difficult or more costly in small entities? 

Describe those circumstances. 

58. The most important goal of the 

regulatory flexibility analysis is to find 

and consider alternatives that may serve 

to meet the goals of OSHA while 

alleviating burden on affected small 

entities. Please suggest and discuss any 

alternatives that might serve to 

minimize these impacts. 

L. Duplication/Overlapping/Conflicting 

Rules 

59. Are there any Federal rules that 

might duplicate, overlap, or conflict 

with any standard that OSHA may 

promulgate on diacetyl or food 

flavorings containing diacetyl? If so, 

please identify which ones and explain 


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how they would duplicate, overlap, or 

conflict. 

60. Are there any Federal programs in 

areas such as defense or energy that 

might be impacted by any standard that 

OSHA may promulgate on diacetyl or 

food flavorings containing diacetyl? If 

so, please identify which ones and 

explain how they would be impacted. 

M. Approaches to Regulation 

Most OSHA health standards apply 

when there is occupational exposure to 

the substance being regulated. Although 

OSHA is aware of possible occupational 

exposures to diacetyl that do not 

involve food flavorings, the known 

cases of occupational lung disease are 

associated with employees exposed to 

food flavorings containing diacetyl. 

Employee exposures to diacetyl may 

occur during processing of foods in 

which diacetyl occurs naturally, such as 

dairy products, wine, and beer; when 

using flavored oils or butter for cooking 

purposes; when making fragrances; and 

when adding fragrances to products. 

Should OSHA cover all occupational 

exposures to diacetyl under a proposed 

standard, or should the standard focus 

on certain industries, processes, or 

applications? Which sectors should 

OSHA consider covering under a 

proposed rule? 

61. Acetoin is a plausible contributor 

to flavoring-related lung disease, given 

its volatility, structural similarity to 

diacetyl, and presence in all of the work 

environments in which elevated 

prevalence of respiratory disease has 

been noted. In addition to diacetyl, 

should OSHA cover occupational 

exposures to acetoin under a proposed 

standard? Please indicate the basis for 

your position and include any 

supporting evidence. 

62. Should OSHA exclude chemical 

mixtures containing diacetyl at 

concentrations below a certain 

threshold from coverage under a 

proposed standard? If so, what 

threshold (i.e., percent content) should 

OSHA consider? Please indicate the 

basis for your position and include any 

supporting evidence. 

63. Should OSHA propose a 

permissible exposure limit (PEL) for 

diacetyl or, instead, should the Agency 

propose process-specific requirements 

for engineering controls, exposure 

monitoring, exposure control planning, 

and respiratory protection (i.e., a nonPEL approach)? Although a PEL 

approach would be consistent with the 

majority of the Agency’s previous 

standards that regulate chemical 

hazards, OSHA typically relies on 

specified engineering and work practice 

controls in regulating safety hazards, so 

such an approach would not be novel. 

OSHA welcomes comments on the 

merits of the two approaches as well as 

any other approaches to addressing 

occupational exposure to diacetyl and 

food flavorings containing diacetyl. 

64. What provisions should OSHA 

include in a proposed standard 

addressing occupational exposure to 

diacetyl and food flavorings containing 

diacetyl? OSHA substance-specific 

health standards typically include 

provisions for exposure monitoring, 

regulated areas, methods of compliance, 

respiratory protection, protective 

clothing and equipment, medical 

surveillance, and training, as well as 

other requirements. Please indicate 

what provisions would or would not be 

appropriate for protecting employees 

from exposure to diacetyl and food 

flavorings containing diacetyl, and 

explain the reasons for your position. 

65. The California Division of 

Occupational Safety and Health (Cal/ 

OSHA) has initiated rulemaking 

proceedings on diacetyl and other food 

flavorings. In March 2007, Cal/OSHA 

released a draft regulatory text titled 

‘‘Occupational Exposure to Food 

Flavorings’’ (Cal/OSHA, 2007). The 

draft regulatory text includes 

requirements for exposure assessment, 

engineering and work practice controls, 

respiratory protection, medical 

surveillance, training and labeling, and 

recordkeeping, but does not establish a 

PEL. Are there any provisions in the 

draft that OSHA should include in a 

proposed rule on occupational exposure 

to diacetyl or food flavorings containing 

diacetyl? Are there any aspects of the 

draft that you consider inappropriate? 

Please explain. 

66. NIOSH has issued an alert entitled 

‘‘Preventing Lung Disease in Workers 

Who Use or Make Flavorings’’ as well as 

recommendations for minimizing 

employee exposures to flavorings and 

flavoring ingredients (NIOSH, 2003). 

Are there any provisions or 

recommendations in those documents 

that OSHA should include in a 

proposed rule on occupational exposure 

to diacetyl or food flavorings containing 

diacetyl? Do you consider any of the 

provisions or recommendations 

inappropriate? Please explain. 

III. Public Participation 

You may submit comments in 

response to this document (1) 

Electronically at http:// 

www.regulations.gov, (2) by hard copy, 

or (3) by facsimile (FAX). All comments, 

attachments, and other materials must 

identify the Agency name and the 

docket number for this document 

(Docket No. OSHA–2008–0046). You 

may supplement electronic submissions 

by uploading document files 

electronically. If, instead, you wish to 

mail additional materials in reference to 

an electronic or FAX submission, you 

must submit three copies to the OSHA 

Docket Office (see ADDRESSES section). 

The additional materials must clearly 

identify your electronic or FAX 

comments by name, date, and docket 

number so OSHA can attach them to 

your comments. 

Because of security-related problems 

there may be a significant delay in the 

receipt of comments by regular mail. For 

information about security procedures 

concerning the delivery of materials by 

express delivery, hand delivery, and 

messenger or courier service, please 

contact the OSHA Docket Office at 202– 

693–2350 (TTY 877–889–5627). 

All comments and submissions in 

response to this Federal Register, 

including personal information, are 

placed in the public docket without 

change. Therefore, OSHA cautions 

against submitting certain personal 

information such as social security 

numbers and birthdates. All comments 

and submissions are listed in the http:// 

www.regulations.gov index; however, 

some information (for example, 

copyrighted material) is not publicly 

available to read or download through 

the Web site. All comments, 

submissions, and supporting materials 

are available for inspection and copying 

at the OSHA Docket Office (see the 

ADDRESSES section of this notice). 

Information on using http:// 

www.regulations.gov to submit 

comments and access dockets is 

available at that Web site. Contact the 

OSHA Docket Office (see ADDRESSES

section) for information about materials 

not available through the OSHA Web 

site and for assistance in using the Web 

site to locate and download docket 

submissions. 

Electronic copies of this Federal 

Register notice are available at http:// 

www.regulations.gov. This document, as 

well as news releases and other relevant 

documents, are also available at OSHA’s 

Web site at http://www.osha.gov. 

IV. References 

Akpinar-Elci M, Travis WD, Lynch DA, 

Kreiss K. 2004. Bronchiolitis Obliterans 

Syndrome in Popcorn Production Plant 

Workers, Eur Respir J. 2004; 24:298–302. 

Bibek R. 2004. Fundamental Food 

Microbiology, CRC Press, pp. 228 and 

608. 

Cal/OSHA. 2007. Occupational Exposure to 

Food Flavorings (Draft Regulatory Text). 

California Department of Industrial 

Relations, Division of Occupational 

Safety and Health. 


jlentini on PROD1PC65 with PROPOSALS2
Federal Register / Vol. 74, No. 12 / Wednesday, January 21, 2009 / Proposed Rules 3947 

CDC. 2007. Fixed Obstructive Lung Disease 

Among Workers in the FlavorManufacturing Industry—California, 

2004–2007, Centers for Disease Control 

and Prevention, Morbidity and Mortality 

Weekly Report. 56(16):389–393. 

ConAgra Foods. 2007. News Release: 

ConAgra Foods Introduces Orville 

Redenbacher’s® and Act II® Microwave 

Popcorn with a New Great Tasting Butter 

Flavoring with No Added Diacetyl. 

ConAgra Foods, Inc. 

ERG. 2007. Support for the Development of 

Economic Profile Data of Diacetyl-Using 

Industries (Microwave Popcorn and 

Flavoring). Eastern Research Group, Inc. 

Interim Final Report: Task Order No. 12, 

Contract No. GS–10F–0125P. 

Egilman D, Mailloux C, Valentin C. 2007. 

Popcorn-worker Lung Caused by 

Corporate and Regulatory Negligence: An 

Avoidable Tragedy, Intern. J. 

Occupational Environ. Health 13:85–98. 

FEMA. 2005. Flavor and Extract 

Manufacturers Association. Poundage 

and Technical Effects Update Survey, p. 

61. 

Hubbs AF, Battelli LA, Goldsmith WT, Porter 

DW, Frazer D, Friend S, Schwegler-Berry 

D, Mercer RR, Reynolds JS, Grote A, 

Castranova V, Kullman G, Fedan JS, 

Dowdy J, Jones WG. 2002. Necrosis of 

nasal and airway epithelium in rats 

inhaling vapors of artificial butter 

flavoring. Toxicol Appl Pharmacol 

185(2):128–35. 

Hubbs AF, Goldsmith W, Kashon M, Frazer 

D. 2008. Respiratory Toxicologic 

Pathology of Inhaled Diacetyl in 

Sprague-Dawley Rats, Toxicol. Pathol. 

36(2):330–344. 

Kanwal R. 2008. Bronchiolitis Obliterans in 

Workers Exposed to Flavoring 

Chemicals, Curr. Opin. In Pulmon. 

14:141–146. 

Kanwal R, Kullman G, Piacitelli C, Boylstein 

R, Sahakian N, Martin S, Fedan K, Kreiss 

K. 2006. Evaluation of FlavoringsRelated Lung Disease Risk at Six 

Microwave Popcorn Plants, JOEM 

48(2):149–157. 

Kreiss K, Gomaa A, Kullman G, Fedan K, 

Simoes EJ, Enright PL. 2002. Clinical 

Bronchiolitis Obliterans in Workers at a 

Microwave-Popcorn Plant, New England 

J. of Med. 347(5):330–338. 

Lockey J, McKay R, Barth E, Dahlsten J, 

Baughman R. 2002. Bronchiolitis 

Obliterans In The Food Flavoring 

Manufacturing Industry. Meeting of the 

American Thoracic Society. 

Lone Star Candle Supply. 2003. Material 

Safety Data Sheet for Marshmallow 

Madness Fragrance Oil. 

Martyny JW, Van Dyke M, Arbuckle S, Towle 

M, Rose CS. 2008. Diacetyl Exposure in 

the Flavoring Industry. Journal of 

Occupational and Environmental 

Hygiene 5:679–688. 

Materna B. 2007. Summary of eight known 

cases of confirmed or obstructive lung 

disease in California food flavor 

manufacturing workers. January 11, 

2007. 

Morgan D, Flake GP, Kirby PJ, Palmer SM. 

2008. Respiratory Toxicity of Diacetyl in 

C57BL/6 Mice, Toxicol. Sci. 105(2):429– 

32. 

NIOSH. 1986. Health Hazard Evaluation 

Report. HETA–85–171–1710: 

International Bakers Services, Inc., South 

Bend, Indiana. 

NIOSH Alert. 2003a. Preventing Lung Disease 

in Workers Who Use or Make Flavoring. 

DHHS Publication Number 2004–110. 

NIOSH 2003b. NIOSH Manual of Analytical 

Methods. Diacetyl: Method 2557 Issue 

1:15 March. 

NIOSH. 2007a. Health Hazard Evaluation 

Report. HETA–2007–0033: Gold Coast 

Ingredients, Inc., Commerce, California. 

Interim Report. 

NIOSH. 2007b. Health Hazard Evaluation 

Report. HETA 2006–0303–3043: Report 

on Severe Fixed Obstructive Lung 

Disease in Workers at a Flavoring 

Manufacturing Plant. Carmi Flavor and 

Fragrance Company, Inc., Commerce, 

CA. 

OSHA. 2007a. Diacetyl and Food Flavorings 

Containing Diacetyl Stakeholder Meeting 

Notes Stakeholder Meeting, Arlington, 

Virginia (October 17, 2007), Meeting 

Summary Report. Available at: http:// 

www.osha.gov/dsg/guidance/101707- 

diacetyl-meeting-notes.html. 

OSHA. 2007b. National Emphasis Program— 

Microwave Popcorn Processing Plants. 

Directive No. CPL 03–00–005. Available 

at: http://www.osha.gov/pls/oshaweb/

owadisp.show_document?p_table=

DIRECTIVES&p_id=3649. 

OSHA. 2007c. Respiratory Disease Among 

Employees in Microwave Popcorn 

Processing Plants. Safety and Health 

Information Bulletin SHIB 09–24– 

07Available at: http://www.osha.gov/dts/ 

shib/shib092107.html. 

OSHA. 2007d. Hazard Communication 

Guidance for Diacetyl and Food 

Flavoring Containing Diacetyl. Available 

at: http://www.osha.gov/dsg/guidance/ 

diacetyl-guidance.html. 

Parmet AJ, Von Essen S. 2003. Rapidly 

Progressive, Fixed Airway Obstructive 

Disease in Popcorn Workers: A New 

Occupational Pulmonary Illness? JOEM 

44(3):216–218. 

Pop Weaver®. 2007. Pop Weaver Introduces 

the First Microwave Popcorn with 

Flavoring Containing No Diacetyl. 

Available at: http:// 

www.popweaver.com/ 

PopWeaverNoDiacetyl.pdf. 

Rose C, VanDyke M, Ellison M, Towle M, 

Martyny J. 2007. Respiratory Symptoms 

and Airflow Limitation in Flavoring 

Manufacturing Workers. Am J Respir Crit 

Care Med 175:A17. 

Turin L. 2007. Diacetyl Derivatives. World 

Intellectual Property Organization. 

Available at: http://www.wipo.int/pctdb/ 

en/wo.jsp?IA=US2006026827&

DISPLAY=STATUS. 

Van Rooy, FGBJ, Rooyackers, JM, Prokop M, 

Houba R, Smit LAM, Heederik DJJ. 2007. 

Bronchiolitis Obliterans Syndrome in 

Chemical Workers Producing Diacetyl 

for Food Flavorings. Am J Respir Care 

Med 176:498–504. 

Van Rooy FGBJ, Smit L, Houba R, Zaat VAC, 

Rooyackers J, Heederik DJJ. 2008. A 

Cross Sectional Study on Lung Function 

and Respiratory Symptoms Among 

Chemical Workers Producing Diacetyl 

for Food Flavoring. Occup Environ Med. 

Sept. 19, 2008. 

V. Authority and Signature 

This document was prepared under 

the direction of Thomas M. Stohler, 

Acting Assistant Secretary of Labor for 

Occupational Safety and Health, U.S. 

Department of Labor. It is issued 

pursuant to sections 4, 6, and 8 of the 

Occupational Safety and Health Act of 

1970 (29 U.S.C. 653, 655, 657), 29 CFR 

part 1911, and Secretary’s Order 5–2007 

(72 FR 31160). 

Signed at Washington, DC, this 14th day of 

January 2009. 

Thomas M. Stohler, 

Acting Assistant Secretary of Labor for 

Occupational Safety and Health. 

[FR Doc. E9–1125 Filed 1–16–09; 8:45 am] 

BILLING CODE 4510–26–P 


jlentini on PROD1PC65 with PROPOSALS2