Occupational Exposure to Diacetyl and Food Flavorings Containing Diacetyl, 3938-3947 [E9-1125]

Agencies

• DEPARTMENT OF LABOR
• Occupational Safety and Health Administration

[Federal Register Volume 74, Number 12 (Wednesday, January 21, 2009)]
[Proposed Rules]
[Pages 3938-3947]
From the Federal Register Online via the Government Printing Office [www.gpo.gov]
[FR Doc No: E9-1125]



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Part VII





Department of Labor





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Occupational Safety and Health Administration



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29 CFR Part 1910



Occupational Exposure to Diacetyl and Food Flavorings Containing 
Diacetyl; Proposed Rule

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

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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.

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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 https://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 https://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 https://www.regulations.gov or the OSHA Docket 
Office at the address above. All documents in the docket are listed in 
the https://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 
https://www.regulations.gov. This notice, as well as news releases and 
other relevant information, also are available at OSHA's Web site at 
https://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 anti-bacterial 
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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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-than-
expected 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).
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    \1\ The 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.
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    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 task-
based 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).
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    \2\ NIOSH 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.
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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 
full-shift 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 co-product 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 one-time 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 dose-
dependant 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 water-soluble 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., fragrance-related 
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, task-oriented, 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

[[Page 3943]]

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 flavoring-related 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 flavoring-
related 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-than-expected 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 dose-response 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 
dose-response behavior? For example, does the form of diacetyl affect 
its respiratory deposition? If so, please explain.

[[Page 3944]]

    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 diacetyl-containing 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 in-house 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 time-weighted 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 cross-sectional findings or 
longitudinal trends that you have observed. Specifically, what 
correlations, if any, have you

[[Page 3945]]

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

[[Page 3946]]

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 non-PEL 
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) 
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