Health Hazard Evaluation Report 2016-0141-3329 Page 1

Evaluation of exposures and respiratory 

health at a coffee roasting and packaging 

facility 

Report No. 2016-0141-3329

October 2018

Randy Boylstein, MS, REHS

Tia McClelland, MPH

Sandra White, MS

U.S. Department of Health and Human Services

Centers for Disease Control and Prevention

National Institute for Occupational Safety and Health
Page 2 Health Hazard Evaluation Report 2016-0141-3329

Contents

Highlights...............................................i

Abbreviations .......................................v

Summary.............................................. 1 

Introduction......................................... 2

Background.......................................... 2

Process Description............................. 6 

Methods ............................................... 8 

Results ................................................ 13

Discussion .......................................... 17

Conclusions........................................ 20

Recommendations............................. 21

Appendix A: Tables............................ 24

References.......................................... 33

Acknowledgements........................... 43

The employer is required to post a copy of this report for 30 days at or near the 

workplace(s) of affected employees. The employer must take steps to ensure 

that the posted report is not altered, defaced, or covered by other material.

The cover photo is a close-up image of sorbent tubes, which are used by the HHE

Program to measure airborne exposures. This photo is an artistic representation that may

not be related to this Health Hazard Evaluation.
Health Hazard Evaluation Report 2016-0141-3329 Page i

We evaluated respiratory health 

and airborne exposures to alphadiketones (diacetyl, 2,3-pentanedione, 

and 2,3-hexanedione), other 

volatile organic compounds, carbon 

monoxide, and carbon dioxide during 

coffee processing. All personal air 

samples collected using the standard 

method were above the National 

Institute for Occupational Safety and 

Health’s recommended exposure 

limit of 5.0 parts per billion for 

diacetyl and 9.3 parts per billion for 

2,3-pentanedione, with a maximum 

diacetyl concentration of 40.5 parts per 

billion and a maximum concentration 

of 2,3-pentanedione of 27.1 parts per 

billion. In addition, air sampling during 

short-term tasks identified several 

tasks (e.g., grinding roasted coffee 

beans, packaging coffee, cleaning the 

roaster, and roasting coffee beans) with 

higher exposures to alpha-diketones, 

including diacetyl, than other tasks. 

Eye, nose, and sinus symptoms 

were the most commonly reported 

symptoms. Wheezing was the most 

common lower respiratory symptom. 

One participant had abnormal 

spirometry. We recommend ventilation 

changes; training employees about 

workplace hazards; and the use 

of personal protective equipment 

if engineering and administrative 

controls do not keep exposures below 

the recommended levels. We also 

recommend instituting a medical 

monitoring program for employees 

who work in the production area.

Highlights of this Evaluation

The Health Hazard Evaluation Program of the National Institute for Occupational Safety and 

Health received a request from the management of a coffee roasting and packaging facility. 

The request included concerns regarding exposures to and health effects from diacetyl and 

2,3-pentanedione during coffee roasting, storing, and grinding. 

What We Did

● We visited the coffee roasting and packaging facility during January 30–February 2, 

2017. 

● We collected full-shift (hours), task 

(minutes), and instantaneous (seconds) 

air samples to measure concentrations 

of the alpha-diketones diacetyl, 

2,3-pentanedione, and 2,3-hexanedione.

● We collected roasted coffee beans 

to measure their emission potential 

for diacetyl, 2,3-pentanedione, and 

2,3-hexanedione.

● We measured real-time air levels of total 

volatile organic compounds, carbon 

monoxide, and carbon dioxide.

● We assessed the ventilation system at the 

facility.

● We administered a health questionnaire to 

employees and performed breathing tests. 

What We Found

● All personal air samples collected using 

the standard method were above the 

National Institute for Occupational Safety 

and Health’s recommended exposure limit 

of 5.0 parts per billion for diacetyl.

● The highest concentration of diacetyl 

measured with a full-shift personal air 

sample using the standard method (with 

tubes) was 40.5 parts per billion from a 

grinder/packager.

● The highest concentration of 

2,3-pentanedione measured with a full-
Page ii Health Hazard Evaluation Report 2016-0141-3329

shift personal air sample using the standard method (with tubes) was 27.1 parts per 

billion from a grinder/packager.

● Levels of diacetyl in the air were higher for tasks involving the grinding of roasted 

coffee beans, packaging coffee, cleaning the roaster, and roasting coffee beans.

● All four roasted coffee beans tested emitted 2,3-pentanedione; two of the four emitted 

diacetyl. 

● Five personal samples from production employees exceeded the NIOSH ceiling limit of 

200 parts per million for carbon monoxide. Samples ranged from 304 to 836 parts per 

million. Area indoor carbon monoxide levels ranged from 0.9 ppm–163.5 ppm.

● Upper respiratory symptoms and flu-like achiness were the most commonly reported 

symptoms. Some employees reported their upper respiratory symptoms were caused or 

aggravated by green coffee dust and ground coffee dust.

● Wheezing or whistling in the chest was the most commonly reported lower respiratory 

symptom. Participants reported that these symptoms were not caused or aggravated by 

an exposure at work. 

● One participant had abnormal spirometry.

What the Employer Can Do

● Ensure employees understand potential hazards (e.g., diacetyl, 2,3-pentanedione, 

carbon monoxide, carbon dioxide, green and roasted coffee dust) in the workplace and 

how to protect themselves.

● Ensure adequate fresh, outdoor air is brought into all occupied spaces of the facility 

at all times, in accordance with American National Standards Institute /ASHRAE 

Standard 62.1-2016.

● Install general room ventilation in the production space and operate it continuously 

during the work-shift.

● Install local exhaust ventilation to reduce air concentrations of alpha-diketones during 

the following tasks: 1) grinding roasted coffee and 2) weighing and packaging roasted 

coffee.

● Avoid the use of compressed air as much as possible during cleaning. Instead, use a 

vacuum system with a high-efficiency particle air filter and wet methods whenever 

possible.

● Until exposures are controlled, provide respiratory protection to be used during tasks 

with elevated exposures, specifically during grinding weighing, and packaging roasted 

coffee. 

● Continue to make N95 disposable filtering-face piece respirators available for voluntary 

use for protection against dust exposure.

● Evaluate the bakery further to identify sources of alpha-diketone exposure by 
Health Hazard Evaluation Report 2016-0141-3329 Page iii

conducting personal air monitoring for diacetyl and 2,3-pentanedione. 

● Encourage employees to report new, worsening, or ongoing respiratory symptoms to 

their personal healthcare providers and to a designated individual at the workplace.

● Institute a medical monitoring program for employees who work in the production area.

What Employees Can Do

● Use any local exhaust ventilation as instructed by your employer when installed.

● As much as possible, avoid placing your head directly above or inside roasted bean 

storage bins.

● Some employees might wish to use N95 disposable filtering-facepiece respirators when 

emptying burlap bags of green beans, cleaning the roaster, or cleaning the green bean 

storage area. 

● Report new, persistent, or worsening respiratory symptoms to your personal healthcare 

provider(s) and a designated individual at your workplace. 

● Participate in your employer’s medical monitoring program as instructed by your 

employer.
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Health Hazard Evaluation Report 2016-0141-3329 Page v

Abbreviations

μg Microgram

°F degrees Fahrenheit

ACGIH® American Conference of Governmental Industrial Hygienists

ANSI American National Standards Institute

AX Area of reactance

CFR Code of Federal Regulations

CO Carbon monoxide

CO2 Carbon dioxide

COHb Carboxyhemoglobin

COPD Chronic obstructive pulmonary disease

DR5-R20 The difference between resistance at 5 and 20 Hertz

FEV1 1-second forced expiratory volume

Fres Resonant frequency

FVC Forced vital capacity

kPa/(L/s) Kilopascals per liter per second

IDLH Immediately dangerous to life or health

IOM Institute of Occupational Medicine

LOD Limit of detection

mL/min Milliliter per minute

NHANES National Health and Nutrition Examination Survey

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PEL Permissible exposure limit

ppb Parts per billion

ppm Parts per million

QC Quality control

R5 Resistance at 5 Hertz

R20 Resistance at 20 Hertz

REL Recommended exposure limit

RH Relative humidity

SMR Standardized morbidity ratio

STEL Short-term exposure limit

TLV® Threshold limit value

TVOC Total volatile organic compound

TWA Time-weighted average
Page vi Health Hazard Evaluation Report 2016-0141-3329

US United States

VOC Volatile organic compound

X5 Reactance at 5 Hertz
Health Hazard Evaluation Report 2016-0141-3329 Page 1

Summary 

The Health Hazard Evaluation Program of the National Institute for Occupational Safety 

and Health received a request from the management of a coffee roasting and packaging 

facility. The request stated concerns regarding exposures to and health effects from diacetyl 

and 2,3-pentanedione during coffee roasting and grinding. During January 31–February 1, 

2017, we conducted an industrial hygiene survey at the facility. The industrial hygiene survey 

consisted of the collection of air samples for the analyses of diacetyl, 2,3-pentanedione, 

and 2,3-hexanedione. Bulk samples were also collected for the analysis of diacetyl, 

2,3-pentanedione, and 2,3-hexanedione emission potential. We used continuous monitoring 

instruments to measure total volatile organic compounds, carbon monoxide, carbon dioxide, 

temperature, and relative humidity in specific areas and during tasks. We also performed a 

ventilation assessment of the coffee production area. On February 2, 2017, we conducted 

a medical survey of production employees that consisted of a health questionnaire and 

breathing tests.

Overall, personal time-weighted average air concentrations of diacetyl and 2,3-pentanedione 

exceeded the National Institute for Occupational Safety and Health recommended exposure 

limits. For diacetyl and 2,3-pentanedione, the NIOSH RELs are 5.0 ppb and 9.3 ppb, 

respectively, as a TWA for up to an 8-hour workday during a 40-hour workweek. We 

identified jobs where some work tasks measured over minutes resulted in relatively higher 

air concentrations of diacetyl than other tasks. Specifically, grinding coffee beans, packaging 

coffee beans, and cleaning the roaster, were associated with diacetyl levels above the 

National Institute for Occupational Safety and Health recommended exposure limit. Overall, 

mucous membrane symptoms, specifically eye, nose, and sinus symptoms, and flu-like 

achiness or achy joints, were the most commonly reported symptoms. Some production 

employees reported their mucous membrane symptoms were caused or aggravated by 

green coffee dust, or ground coffee dust. Wheezing or whistling in the chest was the most 

commonly reported lower respiratory symptom. Participants reported that these lower 

respiratory symptoms were not work-related or aggravated by an exposure at work.One 

participant had abnormal spirometry. We recommend installing general room ventilation in 

the production space and operate it continuously during the work-shift and installing local 

exhaust in areas where higher exposure tasks were observed such as grinding, weighing 

and packaging roasted coffee. We also recommended implementing a medical monitoring 

program for employees who work in the production are to identify any employees who might 

be developing work-related lung disease (e.g., asthma, obliterative bronchiolitis) and to help 

management prioritize interventions to prevent occupational lung disease.
Page 2 Health Hazard Evaluation Report 2016-0141-3329

Introduction

In April 2016, the Health Hazard Evaluation Program of the National Institute for 

Occupational Safety and Health (NIOSH) received a request from the management at a 

coffee roasting and packaging facility. The request stated concerns regarding potential 

employee exposure to diacetyl and 2,3-pentanedione during coffee processing. In January 

and February 2017, we conducted a ventilation assessment, an industrial hygiene survey, 

and a medical survey at the facility. We collected air samples for volatile organic compounds 

(VOCs), including diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We monitored carbon 

monoxide (CO), carbon dioxide (CO2), and total VOCs. After the visit, we provided the 

results of the survey in an interim report. 

Background

Diacetyl and 2,3-Pentanedione 

Diacetyl (2,3-butanedione) and 2,3-pentanedione (acetyl propionyl) are VOCs known as 

alpha-diketones that are added as ingredients in food flavorings used in some food products 

such as microwave popcorn, bakery mixes, and flavored coffee [Day et al. 2011; Kanwal et 

al. 2006; Bailey et al. 2015]. Diacetyl, 2,3-pentanedione, other VOCs, and gases such as CO 

and CO2 are naturally produced and released during the coffee roasting process [Duling et al. 

2016; Raffel and Thompson 2013; Daglia et al. 2007; Nishimura et al. 2003; Newton 2002]. 

Grinding roasted coffee beans produces a greater surface area for off-gassing (sometimes 

called degassing) of these compounds [Akiyama et al. 2003]. Often, coffee roasting facilities 

package newly roasted coffee in permeable bags or in bags fitted with one-way valves to 

allow the coffee to off-gas after it is packaged. Sometimes, newly roasted coffee is placed in 

bins or containers and allowed to off-gas before packaging. 

NIOSH has recommended exposure limits (RELs) for diacetyl and 2,3-pentanedione in 

workplace air (Table 1) [NIOSH 2016]. The NIOSH objective in establishing RELs for 

diacetyl and 2,3-pentanedione is to reduce the risk of respiratory impairment (decreased lung 

function) and the severe irreversible lung disease obliterative bronchiolitis associated with 

occupational exposure to these chemicals. The NIOSH RELs are intended to protect workers 

exposed to diacetyl or 2,3-pentanedione for a 45-year working lifetime. The REL for diacetyl 

is based on a quantitative risk assessment which necessarily contains assumptions and some 

uncertainty. Analytical limitations current at the time were taken into consideration in setting 

the REL for 2,3-pentanedione. The RELs should be used as a guideline to indicate when steps 

should be taken to reduce exposures in the workplace.

These exposure limits and the accompanying recommendations for control of exposures were 

derived from a risk assessment of flavoring-exposed workers. At an exposure equal to the 

diacetyl REL, the risk of adverse health effects is low. NIOSH estimated that about 1 in 1,000 

workers exposed to diacetyl levels of 5 parts per billion (ppb) as a time-weighted average 

(TWA) for 8 hours a day, 40 hours a week for a 45-year working lifetime would develop 

reduced lung function (defined as forced expiratory volume in one second [FEV1] below the 
Health Hazard Evaluation Report 2016-0141-3329 Page 3

lowerlimit of normal) as a result of that exposure. NIOSH predicted that around 1 in 10,000 

workers exposed to diacetyl at 5 ppb for a 45-year working lifetime would develop more 

severe lung function reduction (FEV1 below 60% predicted, defined as at least moderately 

severe by the American Thoracic Society [Pellegrino et al. 2005]). Workers exposed for less 

time would be at lower risk for adverse lung effects.

2,3-Hexanedione

2,3-Hexanedione is also an alpha-diketone that is sometimes used as a substitute for diacetyl 

and is produced naturally during coffee roasting. In a study using animals, there was some 

evidence that 2,3-hexanedione might also damage the lungs, but it appeared to be less 

toxic than diacetyl and 2,3-pentanedione [Morgan et al. 2016]. There are no established 

occupational exposure limits for 2,3-hexanedione.

Carbon Monoxide and Carbon Dioxide

CO and CO2 are gases produced by combustion. They are also produced as a result of 

reactions that take place during coffee roasting. These gases are released during and after 

roasting and grinding by a process called off-gassing [Anderson et al. 2003; Hawley et 

al. 2017]. High exposures to CO and CO2 can cause headache, dizziness, fatigue, nausea, 

altered mentation, rapid breathing, impaired consciousness, coma, and death [Newton 2002; 

Nishimura et al. 2003; Langford 2005; CDC 2013a; Raffel and Thompson 2013; Rose et al. 

2017]. Occupational exposure limits for CO and CO2 are listed in Table 1.

Exposure Limits 

We use mandatory (legally enforceable) and recommended occupational exposure limits 

(OELs) when evaluating workplace hazards. OELs have been developed by federal agencies 

and safety and health organizations to prevent adverse health effects from workplace 

exposures.

Occupational Safety and Health Administration (OSHA) [Mandatory] 

The U.S. Department of Labor’s OSHA permissible exposure limits (PELs) are legal limits 

that are enforceable in workplaces covered under the Occupational Safety and Health Act. 

OSHA PELs represent the legal maximum for a TWA exposure to a physical or chemical 

agent over a work shift [OSHA 2018]. OSHA short-term exposure limits (STELs) are the 

legal maximum average exposure for a 15-minute time period. Some chemicals also have an 

OSHA ceiling value, which represent levels that must not be exceeded at any time. Currently, 

there are no PELs for diacetyl, 2,3-pentanedione, or 2,3-hexanedione. For substances for 

which an OSHA PEL has not been issued, violation of the OSHA General Duty Clause 

can be considered using available occupational exposure references and recommendations 

[OSHA 1993; OSHA 2003], such as the American Conference of Governmental Industrial 

Hygienists (ACGIH®) Threshold Limit Values (TLVs®) and NIOSH RELs.

American Conference of Governmental Industrial Hygienists (ACGIH) [Recommendations] 

ACGIH is a professional, not-for-profit scientific association that reviews existing published, 

peer-reviewed scientific literature and publishes recommendations for levels of substances 

in air based on an 8-hour workday and 40-hour workweek. These recommendations are 
Page 4 Health Hazard Evaluation Report 2016-0141-3329

called TLVs [ACGIH 2018a]. ACGIH TLVs are not standards; they are health-based 

guidelines derived from scientific and toxicological information. ACGIH provides TLV-TWA 

guidelines that are levels that should not be exceeded during any 8-hour workday of a 40hour 

workweek. ACGIH also provides TLV-STEL guidelines which are 15-minute exposure levels 

that should not be exceeded during a workday. Exposures above the TLV-TWA but less than 

the TLV-STEL should be (1) less than 15 minutes, (2) occur no more than four times a day, 

and (3) be at least 60 minutes between exposures [ACGIH 2018a]. Additionally, ACGIH 

provides TLV-Ceiling values, which are levels that should not be exceeded at any time during 

a work shift. The ACGIH TLV-TWA for diacetyl is 10 ppb. The TLV-STEL for diacetyl is 20 

ppb. Currently, there is no TLV-TWA or TLV-STEL for 2,3-pentanedione. ACGIH has placed 

2,3-pentanedione on the 2017 list of Chemical Substances and Other Issues Under Study 

[ACGIH 2018b].

National Institute for Occupational Safety and Health (NIOSH) [Recommendations] 

NIOSH provides RELs as TWA concentrations that should not be exceeded over an 8- or 

10-hour work shift, during a 40-hour workweek [NIOSH 2010]. RELs are intended to 

be protective over a 45-year working lifetime. NIOSH also provides STELs which are 

15-minute TWA exposures that should not be exceeded at any time during a workday 

[NIOSH 2010]. Some chemicals have ceiling values, which are concentrations that should 

not be exceeded at any time [NIOSH 2010]. For some chemicals, NIOSH has established an 

Immediately Dangerous to Life or Health (IDLH) value. An IDLH value is a concentration 

of an air contaminant that can cause death or immediate or delayed permanent adverse 

health effects, or prevent escape from such an environment. Currently, NIOSH has RELs 

and STELs for diacetyl and 2,3-pentanedione. NIOSH does not have a REL or a STEL 

for 2,3-hexanedione. NIOSH does not have ceiling limits or IDLH values for diacetyl, 

2,3-pentanedione, or 2,3-hexanedione. 

For diacetyl and 2,3-pentanedione, the NIOSH RELs are 5.0 ppb and 9.3 ppb, respectively, 

as a TWA for up to an 8-hour workday during a 40-hour workweek (Table 1). The NIOSH 

STELs are 25 ppb for diacetyl and 31 ppb for 2,3-pentanedione [NIOSH 2016]. The NIOSH 

exposure limits do not differentiate between natural and synthetic chemical origin of diacetyl 

or 2,3-pentanedione. Although the NIOSH exposure limit for 2,3-pentanedione is above 

that of diacetyl, 2,3-pentanedione has been shown to be as hazardous as diacetyl [Hubbs 

et al. 2012; Morgan et al. 2012]. The NIOSH REL is higher for 2,3-pentanedione than for 

diacetyl largely because analytic measures were not available in a validated OSHA method 

to detect 2,3-pentanedione at lower levels. The hazard potential probably increases when 

these chemicals occur in combination with each other; having exposure to chemicals with 

the same functional alpha-diketone group and effect on the same system or organ (e.g., 

lungs) can result in additive effects [ACGIH 2017a]. In addition to the REL, NIOSH also 

recommends an action level for diacetyl of 2.6 ppb to be used with exposure monitoring in an 

effort to ensure employee exposures are routinely below the diacetyl REL. When exposures 

exceed the action level, employers should take corrective action (i.e., determine the source of 

exposure, identify methods for controlling exposure) to ensure that exposures are maintained 

below the NIOSH REL for diacetyl [NIOSH 2016].
Health Hazard Evaluation Report 2016-0141-3329 Page 5

Table 1. Personal exposure limits for compounds sampled for during the NIOSH survey, 

January – February 2017.

OSHA* ACGIH NIOSH

Compound PEL TLV STEL REL STEL IDLH

Diacetyl - 10 ppb 20 ppb 5.0 ppb† 25 ppb -

2,3-Pentanedione - - - 9.3 ppb† 31 ppb -

2,3-Hexanedione - - - - - -

Carbon dioxide§ 5,000 ppm 5,000 ppm 30,000 ppm 5,000 ppm 30,000 ppm 40,000 ppm

Carbon 

monoxide§ 50 ppm 25 ppm - 35 ppm 200 ppm (ceiling limit)¶ 1,200 ppm

Note: OSHA=Occupational Safety and Health Administration; ACGIH=American Conference of 

Governmental Industrial Hygienists; NIOSH=National Institute for Occupational Safety and Health; 

PEL=permissible exposure limit; STEL=short-term exposure limit; TLV=threshold limit value; 

REL=recommended exposure limit; IDLH=immediately dangerous to life or health; ppb=parts per 

billion; ppm=parts per million; “-“=no exposure limit available.

*There are no OSHA STELs for the compounds in the table.

†The NIOSH RELs for diacetyl and 2,3-pentanedione are time-weighted averages for up to an 8- hour 

day, during a 40-hour workweek.

§OSHA and NIOSH limits are designed for occupational exposure measurements in manufacturing and 

other trades that have potential sources of carbon dioxide or carbon monoxide (e.g., coffee roasting, 

welding, vehicle exhaust, diesel engine exhaust). Typical levels of carbon monoxide in offices are 0–5 

ppm. In office settings, carbon dioxide generally should not be greater than 700 ppm above outdoor 

carbon dioxide levels; this typically corresponds to indoor concentrations below 1200 ppm. 

¶This is the NIOSH ceiling exposure limit for carbon monoxide. A ceiling concentration should not be 

exceeded at any time.

Obliterative Bronchiolitis

Obliterative bronchiolitis is a serious, often disabling, lung disease that involves scarring of 

the very small airways (i.e., bronchioles). Symptoms of this disease might include cough, 

shortness of breath on exertion, or wheeze, that do not typically improve away from work 

[NIOSH 2012]. Occupational obliterative bronchiolitis has been identified in flavoring 

manufacturing workers and microwave popcorn workers who worked with flavoring 

chemicals or butter flavorings [Kreiss 2013; Kim et al. 2010; Kanwal et al. 2006]. It has 

also been identified in employees at a coffee roasting and packaging facility that produced 

unflavored and flavored coffee [CDC 2013b]. A NIOSH health hazard evaluation at that 

facility found diacetyl and 2,3-pentanedione concentrations in the air that were elevated 

and identified three sources: 1) flavoring chemicals added to roasted coffee beans in the 

flavoring area; 2) grinding unflavored roasted coffee beans and packaging unflavored ground 

and whole bean roasted coffee in a distinct area of the facility, and 3) storing roasted coffee 

in hoppers, on a mezzanine above the grinding/packaging process, to off-gas [Duling et al. 

2016]. At the time of the health hazard evaluation, workers had excess shortness of breath 

and obstruction on spirometry, both consistent with undiagnosed lung disease. Respiratory 

illness was associated with exposure and not limited to the flavoring areas [Bailey et al. 

2015]. However, all workers who were diagnosed with obliterative bronchiolitis had worked 

in the flavoring area. To date, no cases of obliterative bronchiolitis have been reported in 

workers at coffee roasting and packaging facilities that produce only unflavored coffee.
Page 6 Health Hazard Evaluation Report 2016-0141-3329

Work-related Asthma

Work-related asthma refers to asthma that is brought on by (“occupational asthma”) or made 

worse by (“work-exacerbated asthma” or “work-aggravated asthma”) workplace exposures 

[Tarlo 2016; Tarlo and Lemiere 2014; OSHA 2014; Henneberger et al. 2011]. Work-related 

asthma includes asthma due to sensitizers, which cause disease through immune (allergic) 

mechanisms, and asthma due to irritants, which cause disease through non-immune 

mechanisms. Symptoms of work-related asthma include episodic shortness of breath, cough, 

wheeze, and chest tightness. The symptoms can begin early in a work shift, towards the end 

of a shift, or hours after a shift. They generally, but do not always, improve or remit during 

periods away from work, such as on weekends or holidays. 

Green and roasted coffee dust and castor beans (from cross-contamination of bags used 

to transport coffee) are known risk factors for occupational asthma [Figley and Rawling 

1950; Karr et al. 1978; Zuskin et al. 1979, 1985; Thomas et al. 1991]. Persons who become 

sensitized (develop an immune reaction) to coffee dust can subsequently react to relatively 

low concentrations in the air. Others may experience irritant-type symptoms from exposure 

to coffee dust [Oldenburg et al. 2009].

Process Description

This privately owned coffee roasting facility was located in a 2-story brick structure with 

a basement. The building was approximately 128 years old and 15,000 square feet. The 

facility featured a café, offices, production area, quality control (QC) lab, kitchen, storage 

area, and maintenance shop. The café and production area were located on the first floor. 

The offices and kitchen were on the second floor, and green coffee beans storage and 

maintenance shop were in the basement. At the time of the NIOSH visit in February 2017, 

there were approximately 50 employees at the location, with 10 working in production (5-day 

workweek, 8-hour shift). Approximately 1,000 pounds of coffee per day were produced (75% 

whole bean, 25% ground). No flavored coffee was produced. Forty employees did various 

administrative tasks including accounts receivable, customer service, inventory control, 

graphic design, sales, kitchen, and café operations. 

Green Coffee Beans

Green coffee beans were delivered from suppliers in burlap or jute bags to the loading dock 

door. Upon arrival at the facility, bags of green beans were taken to the basement by hand and 

palletized for storage. When needed, bags were brought up to the first floor production area 

and placed near the roaster where employees opened the bags and weighed out batches.

Roasting

Roasting was conducted in a 132-pound maximum capacity roaster with typical roasts 

weighing 75 pounds to 100 pounds. To prepare a batch for roasting green coffee beans, an 

employee weighed green coffee beans and then placed them in a holding funnel at the top 

of the roaster. When ready, the coffee was charged into the roasting drum for 10 minutes to 

15 minutes, depending on roast level. Upon completion, roasted coffee was dropped into a 
Health Hazard Evaluation Report 2016-0141-3329 Page 7

cooling tray directly beneath the roaster for 5 minutes to 10 minutes, and then was fed to the 

destoner/hopper. Then coffee was moved to 60-pound to 80-pound storage bins until bagged. 

Types of roasts included light, medium, and dark roasts. A roaster operator monitored the 

roasting equipment throughout the roasting and cooling process. 

Chaff Cleaning Frequency

The chaff collector was located at the rear of the roaster and cleaned at the end of each day. 

The roaster had an afterburner; the after burner’s filter was changed bi-weekly, and ductwork 

was removed and cleaned quarterly.

Off-gassing

Roasted coffee was stored in 60 pound to 80 pound bins for storage until needed for 

packaging. Coffee off-gassed for 24 hours to 48 hours before packaging.

Grinding

Grinding occurred daily, and the volume depended on orders. The facility had two 5-pound 

and one 66-pound capacity grinders. Approximately 50 to100 grinds were conducted per day 

with each grind lasting 15 seconds to 30 seconds in duration. 

Packaging

Whole bean and ground coffee were hand packed at one of two worktables located in the 

production area or using a semi-automated fractional packager. Whole bean coffee was 

packaged in stand-up plastic zip pouches of various sizes, clear plastic bulk bags, and paper 

bags with a tin tie. Ground coffee was packaged in stand-up zip pouches in various sizes and 

fractional film bags. One-way valves were used on bags to allow for off-gassing.

Maintenance

There was a small maintenance area in the basement with five designated employees 

responsible for maintenance of production, kitchen, and café equipment.

QC Laboratory

The primary purpose of the QC laboratory, located across from the loading docks and 

staging area, was to ensure the quality of the coffee produced at the facility. The roaster 

operator conducted QC daily using a computerized system that produced roast curves. If the 

curve did not meet standards, coffee samples were taken to the QC laboratory for further 

analysis. Weekly QC, was conducted in the QC laboratory. Green coffee beans were roasted 

in a small roaster in the QC laboratory, then ground, and brewed followed by the cupping 

process where quality control staff smelled, tasted, and assigned scores to coffee brewed 

from samples of roasted beans. The roasted beans used for cupping came from three sources: 

green coffee bean samples from farmers (pre-ship), purchased green coffee beans shipped to 

the coffee roasting and packaging facility (arrival), and roasted coffee beans produced at the 

facility (production). 

In addition to cupping, the quality control staff also graded green coffee beans, conducted 

triangulations to certify and grade tasters, and tested packaging. 
Page 8 Health Hazard Evaluation Report 2016-0141-3329

Cleaning Activities

Employees routinely used brooms to sweep the production floor. They also used wet or dry 

wipes on tabletops and equipment surfaces and compressed air to remove coffee bean dust 

from surfaces and equipment. 

Personal Protective Equipment 

Employees were not required to wear a company uniform or protective clothing. N95 

filtering facepiece respirators were available for voluntary use. We did not observe any 

employees wearing respirators.

Ventilation

The production area had no mechanical ventilation other than the exhaust through the roaster. 

Windows and doors were opened, and fans located in some widows operated in the warmer 

months. There was one environmental heater that operated during the colder months.

Methods

We visited the coffee facility during January 30–February 2, 2017. We conducted a 

walkthrough of the facility with management, collected bulk samples and air samples, 

performed a ventilation assessment, and conducted a medical survey of mainly production 

employees. 

We had the following objectives for the health hazard evaluation:

1. Measure employees’ exposure to diacetyl, 2,3-pentanedione, and 2,3-hexanedione 

during coffee roasting and packaging, and café activities;

2. Identify process areas or work tasks associated with emissions of diacetyl, 

2,3-pentanedione, and 2,3-hexanedione;

3. Measure levels of CO and CO2 throughout the facility;

4. Assess ventilation systems and their effect on exposure levels;

5. Determine if employees had mucous membrane, respiratory, or systemic symptoms 

and the proportion of those symptoms that were work-related or aggravated by work;

6. Determine if employees had abnormal lung function tests; and

7. Compare employees’ prevalence of respiratory symptoms and healthcare providerdiagnosed asthma to expected levels based on general population values.

Industrial Hygiene Survey

Sampling Times for Alpha-Diketones 

We designed the sampling strategy to assess full-shift exposures and to identify tasks 

and processes that were the greatest contributors to worker exposure to alpha-diketones. 

Sampling was conducted over multiple days at the roasting and packaging facility and on a 

single day at the café. For diacetyl, 2,3-pentanedione, and 2,3-hexanedione, the air samples 
Health Hazard Evaluation Report 2016-0141-3329 Page 9

were collected over seconds, minutes, and hours. Samples collected over minutes can help 

inform recommendations related to short term exposure limits (STELs) and those collected 

over hours can help determine average concentrations that can be compared with the NIOSH 

RELs for diacetyl and 2,3-pentanedione. These average concentrations might not tell us about 

short-term peak exposures that could be relevant to respiratory health, particularly when tasks 

are repeated multiple times per day. Therefore, during particular tasks, we collected personal 

air samples over several minutes; these samples can provide information about which tasks 

have relatively higher exposures. To help identify point sources of chemicals, we also 

performed real-time sampling and collected instantaneous samples over seconds.

Employees who participated in air sampling were given the opportunity to request their 

individual air sampling results.

Air Sampling and Analysis Using Modified Occupational Safety and Health Administration 

(OSHA) Methods 1013/1016

We collected personal and area air samples for diacetyl, 2,3-pentanedione, and 

2,3-hexanedione on silica gel sorbent tubes during the industrial hygiene survey over 

multiple days. The samples were collected and analyzed according to the modified OSHA 

sampling and analytical Methods 1013/1016 [OSHA 2008; OSHA 2010; LeBouf and 

Simmons 2017]. In accordance with the two methods, two glass silica gel sorbent tubes were 

connected by a piece of tubing and inserted into a protective, light-blocking cover. The tubes 

were connected in series to a sampling pump pulling air through the tubes at a flow rate 

of 50 milliliters per minute (mL/min). The sampling setup was attached to an employee’s 

breathing zone or placed in an area basket in various places throughout the facility. For 

full-shift sampling, we collected two consecutive 3-hour samples and calculated the TWA 

concentration from the two samples, assuming that the total 6-hour monitoring results 

reflected a full work shift (8-hour) TWA exposure. Although this might introduce some 

error, it is a conservative approach that is more protective of employees than the alternative 

assumption of no exposure during the last two hours of the shift. We refer to these samples as 

“full-shift samples” throughout this report. We also collected personal short-term task based 

samples in the same manner, but the sampling pump flow rate was 200 mL/min as detailed in 

OSHA Methods 1013 and 1016 [OSHA 2008; 2010]. Sampling times were dependent on the 

duration of the task being performed. 

Analyses of the samples were performed in the NIOSH Respiratory Health Division’s 

Organics Laboratory. The samples were extracted for one hour in 95% ethanol:5% water 

containing 3-pentanone as an internal standard. Samples from both visits were analyzed using 

an Agilent 7890/7001 gas chromatograph/mass spectrometer system operated in selected 

ion monitoring mode for increased sensitivity compared to the traditional flame ionization 

detector used in OSHA Methods 1013 and 1016 [LeBouf and Simmons 2017].

A limit of detection (LOD) is the lowest mass that an instrument can detect above 

background and is a criterion used to determine whether to report a result from a sample. 

The LODs were 0.010 micrograms per sample (μg/sample) for diacetyl, 0.01 μg/sample for 

2,3-pentanedione, and 0.010 μg/sample for 2,3-hexanedione. For a typical full-shift TWA 
Page 10 Health Hazard Evaluation Report 2016-0141-3329

air sample, these equate to 0.32 ppb for diacetyl, 0.27 ppb for 2,3-pentanedione, and 0.24 

ppb for 2,3-hexanedione. The LODs for task samples vary because of differing air volumes 

collected while sampling specific tasks and are higher than typical LOD values. When the 

values presented in the report are from samples below the LOD they are denoted by a “<” 

symbol.

Air Sampling and Analysis Using Evacuated Canisters

We collected instantaneous task-based and source air samples for VOCs including diacetyl, 

2,3-pentanedione, and 2,3-hexanedione using evacuated canisters. The evacuated canister 

sampling setup consisted of a 450-mL evacuated canister equipped with an instantaneous 

flow controller that was designed for a short sampling duration (less than 30 seconds). 

Instantaneous samples were taken by opening the evacuated canister to grab a sample of 

air to help identify point sources of alpha-diketones. For task-based air samples, a NIOSH 

employee placed the inlet of the flow controller by the employee’s personal breathing zone 

as they performed their work task to replicate exposure. For source air samples, a NIOSH 

employee placed the inlet of the flow controller directly at the source of interest. 

The canister air samples were analyzed using a pre-concentrator/gas chromatograph/

mass spectrometer system pursuant to a published method validation study [LeBouf 

et al. 2012], with the following modifications: the pre-concentrator was a Model 7200 

(Entech Instruments, Inc., Simi Valley, CA), and six additional compounds, diacetyl, 

2,3-pentanedione, 2,3-hexanedione, acetaldehyde, acetonitrile, and styrene, were included. 

At present, this canister method is partially validated [LeBouf et al. 2012] and not considered 

the standard method. For the visit, the LODs were 0.39 ppb for diacetyl, 0.55 ppb for 

2,3-pentanedione, and 0.95 ppb for 2,3-hexanedione based on a three-times dilution factor, 

which is typical for restricted flow controller samplers. However, LODs are dependent on the 

pressure inside each canister after the samples have been collected, and they might be higher 

or lower than typical LOD values. 

Bulk Sampling and Headspace Analysis

We used 50-mL sterile polypropylene centrifuge tubes to collect approximately 40-mL 

bulk samples of roasted coffees (whole bean and ground). For headspace analysis of 

alpha-diketones, we transferred 1 gram of solid bulk material into a sealed 40-mL amber 

volatile organic analysis vial and let it rest for 24 hours at room temperature (70°F) in the 

laboratory. Then 2 mL of headspace air was transferred to a 450-mL canister and pressurized 

to approximately 1.5 times atmospheric pressure. Using the canister analysis system, 

the concentrations were calculated in ppb of analytes in the headspace as an indicator of 

emission potential.

Real-time Air Sampling

We used RAE Systems (San Jose, CA) ppbRAE 3000 (Model #PGM-7340) monitors to 

measure concentrations of total volatile organic compounds (TVOCs) in the air. The ppbRAE 

has a non-specific photoionization detector that responds to chemicals with ionization 

potentials below the energy of the lamp. This sampling was conducted to identify areas 

where coffee could be releasing TVOCs. Areas where higher concentrations of TVOCs are 
Health Hazard Evaluation Report 2016-0141-3329 Page 11

measured might benefit from further sampling to characterize specific exposures to alphadiketones. We also collected real-time measurements of CO2

, CO, temperature, and relative 

humidity (RH) using TSI Incorporated (Shoreview, MN) VelociCalc Model 9555-X MultiFunction Ventilation Meters equipped with Model 982 IAQ probes.

Ventilation Assessment

We used smoked tube to assess airflow patterns at doors throughout the production areas. At 

the time of the survey, all doors were closed between the production area, outside, and other 

areas of the building. 

NIOSH Medical Survey

Participants 

We invited all current production employees to participate in the medical survey at the 

workplace on February 2, 2017. Participation was voluntary; written informed consent was 

obtained from each participant before testing. The survey included, in the order performed, 

a medical and work history questionnaire, quantification of exhaled nitric oxide, impulse 

oscillometry, and spirometry. We mailed participants their individual reports explaining their 

breathing test results and recommended each participant provide the information to their 

personal physician. 

Questionnaire 

We used an interviewer-administered computerized questionnaire to ascertain symptoms 

and diagnoses, work history at this coffee roasting and packaging facility and other coffee 

or flavoring companies, and cigarette smoking history. Questions on respiratory health were 

derived from five standardized questionnaires, the European Community Respiratory Health 

Survey [Burney et al. 1994; ECRHS 2014], the American Thoracic Society adult respiratory 

questionnaire (ATS-DLD-78) [Ferris 1978], the International Union Against Tuberculosis 

and Lung Disease [Burney and Chinn 1987; Burney et al. 1989], and the Third National 

Health and Nutrition Examination Survey (NHANES III) [CDC 1996] and NHANES 2007-

2012 questionnaires [CDC 2018]. Some of the questions appeared on more than one of 

the standardized questionnaires. We also supplemented our questionnaire with additional 

respiratory and systemic symptom questions.

Spirometry

The purpose of the spirometry test was to determine a person’s ability to move air out of 

their lungs. Test results were compared to expected normal values. The test included three 

measurements or calculations: 1) forced vital capacity (FVC), (the total amount of air the 

participant can forcefully blow out after taking a deep breath), 2) FEV1 (the amount of air 

that the participant can blow out in the first second of exhaling), and 3) the ratio of FEV1 to 

FVC. We used American Thoracic Society criteria for acceptability and repeatability [Miller 

et al. 2005]. 

We used a volume spirometer (dry rolling seal spirometer) to measure exhaled air volume 

and flow rates. We used equations for predicted values and lower limits of normal derived 

from NHANES III data to define abnormal spirometry [Hankinson et al. 1999]. We defined 
Page 12 Health Hazard Evaluation Report 2016-0141-3329

obstruction as an FEV1/ FVC ratio less than the lower limit of normal with FEV1 less than the 

lower limit of normal; restriction as a normal FEV1/FVC ratio with FVC less than the lower 

limit of normal; and mixed obstruction and restriction as having FEV1, FVC, and FEV1/FVC 

ratio all less than the lower limit of normal. We used the FEV1 percent predicted to categorize 

such abnormalities as mild, moderate, moderately severe, severe, or very severe [Pellegrino 

et al. 2005]. 

Impulse Oscillometry

Many occupational lung diseases (e.g., chronic obstructive pulmonary disease (COPD), 

asthma) involve the small airways; however, this part of the lung is difficult to evaluate noninvasively. Oscillometry is a helpful technology to understand the effects of occupational 

exposures on the small airways. There are no contraindications to the test as this test is 

conducted using regular breathing and does not require a forceful exhalation [Smith et al. 

2005]. Spirometry can be normal despite respiratory symptoms or evidence of small airways 

disease on lung biopsy [King et al. 2011; Oppenheimer et al. 2007]; therefore, oscillometry 

results complement spirometry and can be used when spirometry is not possible because of a 

contraindication. 

We used an impulse oscillometry machine (CareFusion Corp., San Diego, CA) to measure 

resistance (R), the energy required to propagate the pressure wave through the airways, 

and reactance (X), which reflects the viscoelastic properties of the respiratory system. The 

impulse oscillometry testing machine sends sound waves called pressure oscillations at 

different frequencies (e.g., 5 Hertz and 20 Hertz) into the airways to measure how airways 

respond to these small pressures. The test calculates 1) the airway resistance at different 

frequencies including 5 Hertz (R5) and 20 Hertz (R20), and the difference between R5 

and R20 (DR5-R20); 2) the reactance at different frequencies including 5 Hertz (X5); 3) 

resonant frequency (Fres) which is the frequency where there is no airway reactance; and 

4) the total reactance (AX) at all frequencies between 5 Hertz and the Fres. The predicted 

values for R and X were based on sex and age according to reference values recommended 

by the manufacturer [Vogel and Smidt 1994]. R5 was considered abnormal (elevated) if 

the measured value was equal to or greater than 140 percent of the predicted R5. X5 was 

considered abnormal (decreased) if the value of the predicted X5 minus measured X5 was 

equal to or greater than 0.15 kilopascals per liter per second (kPa/(L/s)). DR5-R20 values 

greater than 30% were considered abnormal and evidence of frequency dependence [Smith 

2015]. We interpreted the test as normal if both the R5 and X5 were normal [Smith 2015]. 

We defined possible large (central) airways abnormality as a normal X5 and elevated R5 

with no evidence of frequency dependence. We defined a possible small airways abnormality 

if there was evidence of frequency dependence and/or a decreased X5 with or without an 

elevated R5. We defined possible combined small (peripheral) and large (central airways) 

abnormality as a decreased X5 and elevated R5 with no evidence of frequency dependence. 

Bronchodilator Reversibility Testing for Impulse Oscillometry and Spirometry 

If a participant had abnormal impulse oscillometry or spirometry, we repeated both tests after 

the participant received a bronchodilator inhaler medication (i.e., albuterol), which can open 

the airways in some individuals (e.g., asthmatics). For oscillometry, we defined reversibility 
Health Hazard Evaluation Report 2016-0141-3329 Page 13

(improvement) after bronchodilator administration as a decrease of at least 20% of either Fres 

or R5 or a decrease of 40% for AX. For spirometry, we defined reversibility (improvement) 

as increases of at least 12% and 200 mL for either FEV1 or FVC after bronchodilator 

administration. 

Fractional Exhaled Nitric Oxide (FeNO) 

We used the NIOX MINO® device (Aerocrine Inc., Morrisville, NC) to measure the amount 

of nitric oxide in the air the participant breathed out. Nitric oxide is a gas that is produced by 

the airways, and elevated levels can be a sign of eosinophilic airway inflammation in asthma 

[Dweik et al. 2011]. In adults, fractional nitric oxide concentration in exhaled breath levels 

above 50 ppb are considered elevated. In adults with asthma, elevated levels may indicate 

that their asthma is uncontrolled [Dweik et al. 2011].

Statistical Analysis 

Industrial Hygiene Survey and Ventilation Assessment

We performed analyses using Excel (Microsoft®, Redmond, WA) and SAS version 9.4 (SAS 

Institute, Cary, NC). We created summary statistics by work area location, job title, and task. 

When the values presented in the report are from samples below the LOD they are denoted 

by a “<” symbol.

Medical Survey

We calculated frequencies and standardized morbidity ratios (SMRs) and their associated 

95% confidence intervals (CI) using SAS version 9.3 (SAS Institute, Cary, NC). The 

SMRs compared prevalences of symptoms and diagnoses among participants to expected 

prevalences of a sample of the general population reflected in the NHANES III (1988–1994) 

or NHANES 2007–2012 adjusting for sex, race/ethnicity, age (less than 40 years old or 40 

years or greater), and cigarette smoking categories (ever/never). For comparisons to the US 

population, we used the most recent NHANES survey available for the specific comparisons. 

The small number of participants limits the conclusions that can be drawn from these 

analyses. Nonetheless, we report these results to provide some context for how commonly 

these symptoms and diagnoses are reported by adults in the general population.

Results

Industrial Hygiene Survey Results

Personal and Area Full-shift Air Sampling Results

OSHA Methods 1013/1016

Table A1 presents the personal and area full-shift air sampling results from our visit in 

January and February 2017. We collected 15 personal and 30 area full-shift air samples. All 

15 personal air samples were above the NIOSH REL for diacetyl of 5.0 ppb and nine of 15 

were above the NIOSH REL for 2,3-pentanedione of 9.3 ppb. A grinder/packager had the 

highest exposure to diacetyl (40.5 ppb) and 2,3-pentanedione (27.1 ppb). A roaster had the 

second highest exposure to diacetyl (34.7 ppb) and 2,3-pentanedione (25.1 ppb). Seven of 

the 15 personal air samples were above the LOD for 2,3-hexanedione. An employee working 
Page 14 Health Hazard Evaluation Report 2016-0141-3329

in the production area had the highest exposure to 2,3-hexanedione (1.3 ppb). The second 

highest exposure of 1.2 ppb was captured in the roasting area.

Areas throughout the coffee roasting and packaging facility such as the bakery, café, 

administration, grinding, packaging, roasting, roasted bean storage, QC lab, warehouse 

and training center had air levels that exceeded the NIOSH REL for diacetyl. Twentythree of 30 area samples for diacetyl and 14 of 30 area samples for 2,3-pentanedione 

exceeded the NIOSH REL. Packaging had the highest diacetyl (10.7 ppb–61.2 ppb) and 

2,3-pentanedione (0.3 ppb–37.9 ppb) air levels. The roasting and roasted storage beans 

area had the second highest air concentrations for diacetyl (36.2 ppb and 41.3 ppb) and 

2,3-pentanedione (29.3 ppb and 28.4 ppb). Eight out of 30 area air samples were above 

the LOD for 2,3-hexanedione. The packaging and roasting areas had the highest air levels 

of 2,3-hexanedione (1.4 ppb and 1.2 ppb). We note that NIOSH RELs are intended to be 

directly compared to personal measurements; therefore, an area air sample that exceeds a 

NIOSH REL is only an indication of potential personal exposures.

Short-Term Task-based Air Sampling Results

OSHA Methods 1013/1016

Table A2 presents the short-term personal task-based air concentrations for diacetyl, 

2,3-pentanedione, and 2,3-hexanedione from our visit in January 2017–February 2017 by 

task. We collected 96 personal task-based air samples. The task of grinding coffee beans 

(13 minute task) had the highest exposure to diacetyl (66.9 ppb) and 2,3-pentanedione (53.8 

ppb). The task of packaging coffee (15 minute task) had the second highest exposure to 

diacetyl (56.0 ppb) and 2,3-pentanedione (46.6 ppb). All samples were below the LOD for 

2,3-hexanedione. 

Evacuated Canisters

Instantaneous Task-based Air Sampling Results

Table A3 presents 19 source air samples that were collected during various tasks. Diacetyl 

concentrations ranged from 5.7 ppb–148 ppb; 2,3-pentanedione concentrations ranged from 

6.6 ppb–94.7 ppb; 2,3-hexanedione concentrations ranged from <1.0 ppb–4.1 ppb. The 

highest concentrations for diacetyl, 2,3-pentanedione, and 2,3-hexanedione were captured 

during the manual mixing of ground coffee inside a metal container. 

Instantaneous Source-based Air Sampling Results

Table A4 presents the 11 source air samples collected during the visit from the following 

locations: 1) five inches above whole dark decaf beans while being scooped into the grinder; 

2) above bins in the middle of the off gas area; 3) at the mouth of a grinder nozzle into a 

barrel (decaf); 4) directly over a bag of five pound medium roast; 5) directly over the cooling 

bin of dark French roast; 6) directly above a bag mouth at first small grinder while grinding 

medium roast; 7) in a bin of dark roast that was roasted 24 hours prior and was ready to 

be mixed into a blended coffee, and 8) in a bin of light/medium roast that was roasted four 

hours prior. Diacetyl concentrations ranged from 31.7 ppb–9062 ppb; 2,3-pentanedione 

concentrations ranged from 18.9 ppb–6897 ppb; 2,3-hexanedione concentrations ranged 

from 1.7 ppb–270 ppb. The highest concentrations of diacetyl, 2,3-pentanedione, and 
Health Hazard Evaluation Report 2016-0141-3329 Page 15

2,3-hexanedione were captured at the first small grinder directly above the mouth of the bag 

while ground medium roast coffee was falling into a bag (9062 ppb, 6897 ppb, 270 ppb). 

Real-time Monitoring: Carbon Dioxide (CO2), Carbon Monoxide (CO), Total Volatile 

Organic Compounds (TVOCs), Temperature, and Relative Humidity (RH)

Table A5 presents the results from real-time monitoring for CO, CO2, temperature, and RH 

collected during the visit. Indoor CO levels ranged from 0.9 ppm–163.5 ppm. The highest 

CO level occurred in the grinding area. CO2 levels within the facility ranged from 271 

ppm–1280 ppm. The highest level of CO2 was captured in the quality control lab. None of 

the CO or CO2 levels collected were above exposure limits. Recorded temperatures ranged 

from 66.1–88.3°F during the survey. The highest temperatures (77.4–88.3°F) were captured 

near the roaster. Low levels of RH (13.2–32.3) were present during the sampling period, 

which could be attributed to seasonal conditions. During the visit, we also collected total 

VOCs in various locations throughout the facility including packaging, roasting, grinding, 

quality control lab/cupping room, and the bakery. The highest total VOCs were captured in 

the packaging, grinding, and roasting areas, and the QC lab; the highest exposure occurred in 

roasting. 

Table A6 presents the results from the 11 real-time personal CO measurements collected 

on production employees, roasters, QC personnel, and a bakery employee during the visit. 

Elevated levels of CO were observed among four production employees; maximum levels 

ranged from 8 ppm–836 ppm. Elevated maximum levels of CO could be contributed to 

handling of freshly ground and whole bean coffee during tasks such as weighing and hand 

packing. In the production area, five personal samples (range: 304 ppm–836 ppm) exceeded 

the NIOSH ceiling limit of 200 ppm. The personal sample captured on a roaster (60 ppm) 

revealed low levels of CO, possibly because of the ventilation exhaust of the roaster. 

Increased concentrations of TVOCs were identified around areas that roasted, ground, or 

packaged roasted coffee. Additionally, an increased concentration was found in the cupping 

room. 

Bulk Samples and Headspace Results

Table A7 presents the bulk sample results using headspace analysis. Air concentrations of 

diacetyl ranged from below the limit of detection to 323 ppb for whole bean coffee. Air 

concentrations of 2,3-pentanedione ranged from 201 ppb to 500 ppb for whole bean coffee. 

The bulk samples for whole bean coffee were collected from the whole bean coffee storage 

bins. There was a 4 month storage time before bulk samples were analyzed, which may have 

affected the results. 

Ventilation Assessment

The production area had no mechanical ventilation at the time of the survey. The only source 

of ventilation in the production area was an exhaust stack that served the roaster and the 

use of open windows and doors during the warmer months. Fans were also operated during 

the warmer months in some windows. Through the use of smoke tubes, the production area 

was found to be under negative pressure with respect to the outside and other areas of the 
Page 16 Health Hazard Evaluation Report 2016-0141-3329

building. In other words, air was being drawn into the production area and out the roaster 

exhaust stack. 

Medical Survey Results 

Demographics

Eight of 11 (73%) employees that performed coffee production tasks in either the production 

or quality control/training areas participated in the medical survey. The majority of 

participants were male (63%), and all were Caucasian, with a mean age of 31 years and 

average tenure at the company of 5.7 years. None of the participants were current smokers, 

although six (75%) reported a former smoking history. 

All eight participants reported working or entering the production area, ranging from 

one hour to 40 hours a week, with an average of 25 hours per week. In addition, all had 

performed tasks or activities related to coffee processing in the production area. Most 

reported working with green beans (n=6) and/or grinding roasted beans (n=5). 

Symptoms and Self-Reported Diagnoses

The prevalences of symptoms over the last year and last four weeks at the time of the 

survey are listed in Table A8. Nasal symptoms were the most commonly reported symptom 

(n=7, 88%), followed by eye and sinus symptoms (both: n=4, 50%). Less than half of the 

participants noted that their symptoms improved when away from work and/or were caused 

or aggravated by exposures at work, including dust and coffee grounds. 

Wheeze was the most commonly reported lower respiratory symptom (n=2, 25%), followed 

by trouble with breathing (n=1, 13%). No participants reported that these lower respiratory 

symptoms were work-related or aggravated by an exposure at work.

Flu-like achiness or achy joints was the most commonly reported systemic symptom (n=4, 

50%). One (13%) participant reported that this was aggravated at work and improved when 

away from work. 

One participant reported a diagnosis of asthma prior to employment at the coffee roasting and 

packaging facility. One participant reported a diagnosis of hay fever.

Medical Tests

Two participants had possible breathing test abnormalities. One spirometry test was 

interpreted as having a possible airways obstruction. One impulse oscillometry test was 

interpreted as indicating a possible large airways abnormality. There were no participants 

with elevated nitric oxide levels. 

NHANES Comparison of Symptoms and Diagnoses

The prevalence of selected symptoms (including wheeze and shortness of breath) and 

diagnoses (including asthma) among participants was not different than expected from 

comparisons to the general U.S. population.
Health Hazard Evaluation Report 2016-0141-3329 Page 17

Dicussion

At the coffee roasting and packaging facility that is the subject of this report, the highest 

area samples for total VOCs, CO, diacetyl, and 2,3-pentanedione were observed in 

production areas where coffee was packaged, ground, and roasted; in areas where roasted 

coffee was stored; and in the QC area during cupping activities. Diacetyl, 2,3-pentanedione, 

2,3-hexanedione, other VOCs, and other chemicals such as CO and CO2 are naturally 

produced when coffee beans are roasted, and grinding the roasted coffee beans produces 

greater surface area for the off-gassing of these chemicals [Anderson et al. 2003; Akiyama 

et al. 2003; Daglia et al. 2007; Newton 2002; Nishimura et al. 2003; Raffel and Thompson 

2013]. Occupational exposure to diacetyl and 2,3-pentanedione can cause loss of lung 

function and the lung disease obliterative bronchiolitis [NIOSH 2016]. 

Alpha-Diketones 

Personal Full-shift Sampling

All full-shift personal (two bakers, five grinders/packagers, four production office staff, 

two quality control workers, and two roasters) air samples were above the NIOSH REL

for diacetyl and 60% of full-shift personal air samples were above the NIOSH REL for 

2,3-pentanedione. People who grind and package roasted coffee (40.5 ppb for diacetyl and 

27.1 ppb for 2,3-pentanedione) had the highest exposures followed by employees who roast 

coffee (34.7 ppb for diacetyl and 25.1 ppb for 2,3-pentanedione). The observed full-shift 

exposure levels were influenced by peak exposures that occurred during roasting, grinding, 

and packaging coffee beans followed by periods of lower exposures. Alpha-diketone 

emissions of diacetyl and 2,3-pentanedione into the workplace air are directly related to the 

amount of roasted coffee being produced. The two personal (7.7 ppb and 8.5 ppb) air samples 

collected in the bakery area that exceeded the NIOSH REL for diacetyl were most likely 

caused by the use of butter and flavorings containing butter or diacetyl in the bakery. During 

the sampling, a table located in the bakery had recently been stacked with over 20 one-pound 

loaves of butter to be used in pastry making. 

As noted earlier, the REL should be used as a guideline to indicate when steps should be 

taken to reduce exposures in the workplace. The risks associated with the measured levels are 

higher than NIOSH recommends. As described in the quantitative risk assessment from the 

NIOSH Criteria Document (Tables 5-27 and 5-34) [NIOSH 2016], after a 45-year working 

lifetime exposure to 20 ppb (a concentration lower than the highest concentration measured 

at this facility), NIOSH estimated about 5 in 1,000 workers would develop reduced lung 

function (FEV1 below the lower limit of normal). NIOSH predicted 5 in 10,000 workers 

exposed to diacetyl at 20 ppb would develop more severe lung function reduction (FEV1

below 60% predicted, defined as at least moderately severe by the American Thoracic 

Society [Pellegrino et al. 2005]). After a 45-year working lifetime exposure to 50 ppb (a 

concentration higher than the highest concentration of 40.5 ppb measured at the facility), 

NIOSH estimated that about 12 in 1000 workers would develop reduced lung function (FEV1

below the lower limit of normal). NIOSH predicted about 12 in 10,000 workers exposed 

to diacetyl at 50 ppb would develop more severe lung function reduction. The effects of a 

working lifetime exposure at 40.5 ppb is closer to 50 ppb than 20 ppb. NIOSH recommends 
Page 18 Health Hazard Evaluation Report 2016-0141-3329

keeping diacetyl concentrations below 5 ppb because at this level, the risk of reduced 

lung function after a working lifetime of exposure is about 1 in 1000 workers. NIOSH 

recommends taking steps to reduce diacetyl exposures to below the REL of 5 ppb whenever 

possible.

Task-Based Exposures

Coffee processing involves multiple tasks that might cause intermittent exposure to 

diacetyl and 2,3-pentanedione. Traditional full-shift sampling will not characterize these 

intermittent, peak exposures. Evaluating intermittent and task-based exposures to diacetyl 

and 2,3-pentanedione is difficult with current validated sampling methods (OSHA Methods 

1013/1016). Because tasks are so sporadic in coffee processing, with some only lasting a few 

seconds or minutes, we used instantaneous evacuated canisters to sample tasks that lasted 

only a few seconds to minutes and OSHA Methods 1013/1016 for longer duration tasks. We 

sampled by task, with varying durations, to understand which tasks might have contributed to 

higher exposures to diacetyl and 2,3-pentanedione. 

Our task-based air sampling revealed that some tasks had higher air concentrations of 

diacetyl and/or 2,3-pentanedione than other tasks. As noted earlier, four 15-minute personal 

air samples taken during grinding roasted coffee exceeded the STEL for diacetyl and 

2,3-pentanedione. The maximum concentrations were 66.9 ppb for diacetyl and 53.8 ppb for 

2,3-pentanedione. The greater surface area for off-gassing produced during grinding could 

have resulted in the higher air concentrations [Akiyama et al. 2003].

Carbon Monoxide 

The grinding area had the highest level of CO (163.5 ppm). Five personal CO samples 

(range: 304 ppm–836 ppm) exceeded the NIOSH ceiling limit of 200 ppm. These levels 

could be contributed to handling freshly ground and whole bean coffee during tasks such as 

weighing and hand packaging. 

Bulk Samples

Diacetyl is not found in green beans and forms later in the coffee roasting process [Daglia et 

al. 2007]. As expected, we found that roasted coffee emits alpha-diketones into the headspace 

of sealed vessels, indicating that roasted coffee is a source of alpha-diketones in the facility. 

Caution should be taken when interpreting these results because bulk samples collected 

during our visit were not analyzed immediately after sampling, and the samples had time 

to off-gas before performing the headspace analysis. We also do not know how long the 

beans were in the storage bins before collecting the samples, but generally the time between 

roasting and packaging is hours to days. The amount of time roasted beans had off-gassed 

could be responsible for differences in headspace analysis results. 

Medical Survey 

Overall, mucous membrane symptoms, specifically eye, nose, and sinus symptoms, were 

the most commonly reported symptoms. Some production employees reported their mucous 

membrane symptoms were caused or aggravated by green coffee dust or roasted coffee 

dust. Coffee dust is an organic dust known to cause respiratory symptoms [Zuskin et al. 
Health Hazard Evaluation Report 2016-0141-3329 Page 19

1993; Sakwari et al. 2013]. Green and roasted coffee dust and castor beans (from crosscontamination of bags used to transport coffee) are known risk factors for occupational 

asthma [Figley and Rawling 1950; Karr et al. 1978; Zuskin et al. 1979, 1985; Thomas 

1991]. Persons who become sensitized (develop an immune reaction) to coffee dust can 

subsequently react to relatively low concentrations in the air. Others can experience irritanttype symptoms from exposure to coffee dust [Oldenburg et al. 2009]. 

Upper respiratory disease such as allergic rhinitis (hay fever, nasal allergies) and sinusitis are 

sometimes associated with lower respiratory symptoms and asthma and might precede the 

diagnosis of asthma [Shaaban et al. 2008; EAACI Task Force on Occupational Rhinitis et 

al. 2008; Rondón et al. 2012, 2017; Sahay et al. 2016]. Upper respiratory involvement (e.g., 

rhinitis, sinusitis) can result in suboptimal control of asthma. All participants that reported 

lower respiratory symptoms also reported nasal or sinus problems. Green coffee dust is 

thought to be a more potent allergen than roasted coffee dust because roasting destroys some 

of the allergenic activity [Lehrer et al. 1978].As discussed in the recommendations section, 

one way to prevent symptoms related to green coffee dust and chaff might be to make N-95 

disposable filtering facepiece respirators available for voluntary use when working with green 

beans and chaff.

The number of participants with physician-diagnosed asthma was not different from that 

observed in the U.S. population. Two participants (25%) reported one or more lower 

respiratory symptoms in the 12 months before the medical survey. Neither participant 

reported their lower respiratory symptoms were work-related. Asthma symptoms often 

improve when away from exposures that trigger symptoms while other lung diseases such 

as obliterative bronchiolitis or COPD generally do not improve. Spirometry can be used to 

help detect and follow individuals with asthma and other lung diseases such as obliterative 

bronchiolitis or COPD. Spirometry can show if air is exhaled from the lungs more slowly 

than normal (i.e. obstructive abnormality) or if the amount of air exhaled is smaller than 

normal (i.e., restrictive abnormality). In asthma, there is intermittent airways obstruction 

which is reversible after treatment with bronchodilator medications (e.g., albuterol). In 

obliterative bronchiolitis, scar tissue prevents the small airways (bronchioles) from opening 

up when albuterol is given. In other words, the airways are fixed and not responsive 

(reversible) to bronchodilator medicine. The obstructed airways prevent rapid emptying of 

the lung air sacs (alveoli) during exhalation. This explains why the respiratory symptoms of 

those with occupational obliterative bronchiolitis do not tend to improve when away from 

work-related exposures; however, avoidance of further exposure can stop progression of the 

disease [Akpinar-Elci et al 2004]. 

Spirometry and impulse oscillometry measure different things. Spirometry assesses airflow 

while impulse oscillometry accesses the airways response to a sound or pressure wave. In 

general, during the impulse oscillometry test, a small pressure impulse (sound wave) is 

imposed upon the inspiratory and expiratory airflow during normal tidal breathing. This 

pressure wave causes a disturbance in the airflow and pressure, and the response of the 

airways (i.e., change in pressure to change in flow) is a measure of the resistance to airflow 

in the airways [Desiraju and Agrawal 2016]. Impulse oscillometry can be useful as an 
Page 20 Health Hazard Evaluation Report 2016-0141-3329

indirect measure of airflow obstruction and helpful in individuals not able to perform forced 

breathing maneuvers that are required during the spirometry test. The impulse oscillometry 

test has been used for many years to measure changes in the airways of children with lung 

problems such as asthma and cystic fibrosis [Song et al. 2008; Komarow et al. 2011; Shi 

et al. 2012; Schulze et al. 2016]. More recently, impulse oscillometry has been used to 

investigate lung problems in adults exposed to dust or chemicals, such as World Trade Center 

emergency responders and soldiers returning from deployment overseas [Oppenheimer et al. 

2007; Berger et al. 2013; Weinstein et al. 2016]. Over the years, researchers have developed 

reference (predictive) equations for different populations of children for oscillometry 

[Malmberg et al. 2002; Park et al. 2011; Lee et al. 2012; de Assumpção et al. 2016]. For 

adults, there are fewer reference equations available for oscillometry [Vogel and Smidt 1994; 

Newbury et al. 2008; Schulz et al. 2013]. The predicted values we used for oscillometry 

measures were based on gender and age according to references values recommended by 

the manufacturer. Unlike predictive equations used for spirometry, the impulse oscillometry 

reference equations we used did not take into account height, race, or smoking status [Vogel 

and Smidt 1994].

Among the eight participants, two had abnormal breathing tests. The lower respiratory 

symptoms and breathing test abnormalities are not specific to a particular respiratory problem 

or disease. They could be related to workplace exposures or to other factors. The upper 

respiratory symptoms reported to improve away from work were likely related to workplace 

exposures. Because of the small number of participants and the need to protect individuals’

privacy, we cannot provide more detailed results that might shed light on possible workrelatedness, such as health measures by job title or task. We mailed each participant their 

individual lung function test results with an explanation of the results and recommended each 

participant provide the information to their personal physician.

We recommend starting a medical monitoring program because air sampling found 

concentrations of diacetyl and 2,3-pentanedione above the NIOSH REL. All production 

employees and any employees that assist with production tasks (e.g., roasting, interacting 

with open storage bins/containers of roasted coffee, grinding, weighing, or packaging 

coffee) and bakery employees should participate in the workplace medical monitoring 

program. A medical monitoring program is a means of early identification of employees 

who might be developing lung disease (e.g., asthma, obliterative bronchiolitis) and can help 

prioritize interventions to prevent occupational lung disease. The NIOSH medical survey 

results can serve as a baseline for employees who participated. In a workplace with risk 

of occupational lung disease, prevention of smoking-related lung disease is important and 

makes the detection of work-related adverse effects easier. The Centers for Disease Control 

and Prevention offers tools and resources for setting up a smoking cessation program [CDC 

2017].

Conclusions 

We identified specific work tasks that resulted in air concentrations of diacetyl that should 
Health Hazard Evaluation Report 2016-0141-3329 Page 21

be addressed. Grinding roasted coffee beans, packaging coffee, cleaning the roaster, and 

roasting coffee beans were associated with diacetyl and 2,3-pentanedione levels above 

the NIOSH RELs, and grinding coffee beans and packaging coffee were associated with 

2,3-pentanedione levels above the NIOSH REL; these were likely caused by the close 

proximity of the employee’s breathing zone to the roasted beans. However, five personal CO 

samples exceeded the NIOSH ceiling level of 200 ppm. Area CO and CO2 levels were low 

throughout most of the facility, aside from the grinding area where the highest CO (163.5 

ppm) and CO2 (1280 ppm) levels were observed. 

Overall, mucous membrane symptoms, specifically eye, nose, and sinus symptoms, were 

the most commonly reported symptoms. Some participants noted that their symptoms 

improved when away from work or were aggravated by exposures at work, including dust 

and coffee grounds. Wheezing or whistling in the chest was the most commonly reported 

lower respiratory symptom followed by trouble with breathing. No participants reported 

that these lower respiratory symptoms were work-related or aggravated by an exposure at 

work. Two of eight participants had abnormal breathing tests. We recommend a medical 

monitoring program to identify any employees who might be developing lung disease (e.g., 

asthma, obliterative bronchiolitis) and to help management prioritize interventions to prevent 

occupational lung disease. All production employees, employees who assist with production 

tasks (e.g., roasting, interacting with open storage bins/containers of roasted coffee, grinding, 

weighing, or packaging coffee), and bakery employees should participate in the workplace 

medical monitoring program.

Recommendations 

On the basis of our findings, we recommend the actions listed below. Our recommendations 

are based on an approach known as the hierarchy of controls. This approach groups actions 

by their likely effectiveness in reducing or removing hazards. In most cases, the preferred 

approach is to eliminate hazardous materials or processes and install engineering controls 

to reduce exposure or shield employees. Until such controls are in place, or if they are not 

effective or feasible, administrative measures and personal protective equipment might be 

needed. 

Engineering Controls

Engineering controls reduce employees’ exposures by removing the hazard from the process 

or by placing a barrier between the hazard and the employee. Engineering controls protect 

employees effectively without placing primary responsibility of implementation on the 

employee.

1. Consult with a ventilation engineer to install a dilution ventilation system that meets 

current local mechanical codes. This system should consistently supply fresh, outdoor 

air to the production space. If properly selected, it could also be used to help heat 

and cool the production space throughout the year. The system should be operated 

whenever production activities are ongoing, but it could be shut off during unoccupied 
Page 22 Health Hazard Evaluation Report 2016-0141-3329

periods. Operating this equipment will help dilute and remove airborne alphadiketones (e.g., diacetyl and 2,3-pentanedione) and CO as they are generated and help 

maintain the production space under negative pressure relative to the administrative 

offices.

2. Consult with a ventilation engineer to install local exhaust ventilation during grinding 

roasted coffee and weighing and packaging coffee.

Administrative Controls

The term administrative controls refers to employer-dictated work practices and policies 

to reduce or prevent hazardous exposures. Their effectiveness depends on employer 

commitment and employee acceptance. Regular monitoring and reinforcement are necessary 

to ensure policies and procedures are followed consistently.

1. Install a CO monitor and alarm in the production area that can alert employees if CO 

levels exceed the NIOSH ceiling of 200 ppm. Employees should evacuate and move to 

an area of fresh air until the CO level drops below 200 ppm.

2. After engineering controls have been installed, conduct personal air monitoring for 

diacetyl and 2,3-pentanedione on employees with primary duties in the production area 

using OSHA Sampling Method 1012 for diacetyl [OSHA 2008] and OSHA Sampling 

Method 1016 for 2,3-pentanedione [OSHA 2010]. Because air levels of VOCs 

like diacetyl and 2,3-pentanedione might fluctuate day to day based on production 

schedules, we recommend personal air sampling for diacetyl and 2,3-pentanedione 

over multiple days. 

3. The bakery should be evaluated further to identify sources of alpha-diketone exposure 

by conducting personal air monitoring for diacetyl and 2,3-pentanedione. 

4. Periodically clean the roasters’ exhausts in accordance with manufacturer instructions 

to remove chaff build up to reduce a fire hazard and to improve the efficiency, energy 

usage, and roaster performance. 

5. Include roaster exhaust checks and any future local exhaust systems in a preventive 

maintenance schedule to ensure they operate appropriately.

6. Continue to cover bins of roasted beans to reduce the overall emission of 

alpha-diketones and other chemicals (e.g., CO, CO2) into the workplace and lower 

worker exposure.

7. To reduce exposures to VOCs (including alpha-diketones), CO, and CO2, minimize 

production tasks that require employees to place their heads inside the roasted bean 

bins. 

8. Do not blend roasted beans by hand. Instead, use the agitator of the cooling drum or 

some other automatic mechanism that minimizes employee contact with roasted beans 

during blending. 

9. Eliminate the use of compressed air and dry sweeping as much as possible during 

cleaning. Instead, use a vacuum system with a high-efficiency particle air filter and wet 
Health Hazard Evaluation Report 2016-0141-3329 Page 23

methods whenever possible. 

10.Ensure employees understand potential hazards (e.g., diacetyl, 2,3-pentanedione, 

carbon monoxide, carbon dioxide, green and roasted coffee dust) in the workplace and 

how to protect themselves. OSHA’s Hazard Communication Standard, also known as 

the “Right to Know Law” [29 CFR 1910.1200] requires that employees are informed 

and trained on potential work hazards and associated safe practices, procedures, and 

protective measures. 

11.Ensure employees are educated to consider the risks of further exposure if they 

develop lower respiratory symptoms (e.g., cough, shortness of breath, wheezing) 

that are progressive and severe in degree. Employees should report new, persistent, 

or worsening symptoms to their personal healthcare providers and to a designated 

individual at this workplace. Employees with new, persistent, or worsening symptoms 

should share this report with their healthcare providers.

Personal Protective Equipment

The effectiveness of respiratory protection as personal protective equipment depends on 

avoiding breakdowns in implementation can cause insufficient protection from respiratory 

exposures. Proper use of respiratory protection (respirators) requires a comprehensive 

respiratory protection program and a high level of employee and management involvement 

and commitment to assure that the right type of respirator is chosen for each hazard, 

respirators fit users and are maintained in good working order, and respirators are worn when 

they are needed. Supporting programs such as training, change-out schedules, and medical 

assessment might be necessary. Respirators should not be the sole method for controlling 

hazardous inhalation exposures. Rather, respirators should be used until effective engineering 

and administrative controls are in place. 

1. In addition to engineering and administrative controls, respiratory protection is a 

potential option to further reduce exposures to alpha-diketones (e.g., diacetyl and 

2,3-pentanedione). If respiratory protection is used, NIOSH-certified respirators should 

be fitted with organic vapor cartridges and particulate filters. The choice of respirator 

should be guided by personal exposure sampling for diacetyl and 2,3-pentanedione 

NIOSH 2004). Respirators have assigned protection factors (APF). APF refers to the 

highest level of protection a properly selected respirator can provide. For instance, 

air-purifying half-face respirators have an APF of 10, and air-purifying full-face 

respirators have an APF of 50. Also, there are powered-air purifying respirators that 

have APFs of 25, 50, or 1000. The OSHA APFs can be found in Table 1 of OSHA 

Respiratory Protection Standard at https://www.osha.gov/pls/oshaweb/owadisp.show_

document?p_table=STANDARDS&p_id=12716. 

If mandatory respiratory protection is used, a written respiratory protection program 

should be implemented as required by the OSHA Respiratory Protection Standard (29 

CFR 1910.134), including training, fit testing, maintenance and use requirements. 
Page 24 Health Hazard Evaluation Report 2016-0141-3329

Please be aware that disposable N95 filtering facepiece respirators are not protective 

against alpha-diketones (diacetyl, 2,3-pentanedione, or 2,3-hexanedione). In cases of 

dual exposure to dust and alpha-diketones, NIOSH-certified organic vapor cartridges 

(for the alpha-diketones) and particulate cartridges/filters (for the dust) would be 

warranted.

Medical Monitoring

The purpose of a medical monitoring program is to help assure the health of employees 

who have workplace exposures (e.g., diacetyl, 2,3-pentanedione, green coffee beans/dust) 

known to pose risk for potentially serious health conditions such as asthma or obliterative 

bronchiolitis. 

1. Institute a medical monitoring program for employees who work or assist in the coffee 

production area or bakery. The medical monitoring should consist of evaluation with 

a questionnaire (to obtain health and work task information) and spirometry (to assess 

lung function) at baseline and at one year to monitor for respiratory symptoms and 

to establish employees’ baseline in lung function and any abnormal decline in lung 

function in the first year. Subsequently, an annual questionnaire evaluation should 

occur to monitor for respiratory symptoms. New or worsening respiratory symptoms 

should prompt additional evaluation including spirometry. Details about spirometry 

and a medical monitoring program can be found in chapter 9 of the NIOSH Criteria 

Document [NIOSH 2016].

2. If an employee is identified as likely having lung disease from exposure to diacetyl 

or 2,3-pentanedione, it should be viewed as a sentinel event indicating there was a 

breakdown in exposure controls and there is potential risk for co-workers. Should 

this occur, the unanticipated source of exposure must be identified and brought under 

control. In addition, increased intensity of medical surveillance would be required for 

all employees performing similar job tasks or having similar or greater potential for 

exposure. The NIOSH Criteria Document provides detailed guidance on responses to 

such sentinel events [NIOSH 2016].

Smoking Cessation Program

In a workplace with risk of occupational lung disease, prevention of smoking-related lung 

disease is important and makes the detection of work-related adverse effects easier. None of 

the participants reported current cigarettes smoking. However, if other employees smoke, we 

recommend implementing a smoking cessation program to assist employees to stop smoking. 

The Centers for Disease Control and Prevention offers tools and resources for setting up a 

smoking cessation program [CDC 2017].
Health Hazard Evaluation Report 2016-0141-3329 Page 25

Table A1. OSHA Methods 1013/1016 full-shift personal and area air sampling results by location, 

January–February 2017.

Analyte Sample 

Type Location N

Above 

LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Above 

REL N 

(%)

Diacetyl Personal Bakery 2 2 (100%) 7.7 8.5 2 (100%)

Diacetyl Personal Production Area 5 5 (100%) 12.8 40.5 5 (100%)

Diacetyl Personal Production Office 4 4 (100%) 7.4 30.4 4 (100%)

Diacetyl Personal QC Lab 2 2 (100%) 7.5 12.7 2 (100%)

Diacetyl Personal Roasting 2 2 (100%) 19.5 34.7 2 (100%)

Diacetyl Area Admin 2 2 (100%) 4.1 6.6 N/A

Diacetyl Area Bakery 2 2 (100%) 6.3 6.8 N/A

Diacetyl Area Café 4 4 (100%) 3.0 29.0 N/A

Diacetyl Area Green Bean Storage 2 1 (50%) <0.5 3.5 N/A

Diacetyl Area Grinding 2 2 (100%) 19.5 28.6 N/A

Diacetyl Area Maintenance Shop 2 2 (100%) 2.0 4.7 N/A

Diacetyl Area Packaging 4 4 (100%) 10.7 61.2 N/A

Diacetyl Area QC Lab 2 2 (100%) 6.4 11.7 N/A

Diacetyl Area Roasted Bean Storage 4 4 (100%) 19.3 41.3 N/A

Diacetyl Area Roasting 2 2 (100%) 20.8 36.2 N/A

Diacetyl Area TRAINING CENTER 2 2 (100%) 6.2 10.6 N/A

Diacetyl Area WAREHOUSE 2 2 (100%) 7.6 12.3 N/A

2,3-Pentanedione Personal Bakery 2 2 (100%) 4.8 5.8 0 (0%)

2,3-Pentanedione Personal Production Area 5 5 (100%) 10.4 27.1 5 (100%)

2,3-Pentanedione Personal Production Office 4 4 (100%) 6.9 21.2 1 (25%)

2,3-Pentanedione Personal QC Lab 2 2 (100%) 5.4 10.1 1 (50%)

2,3-Pentanedione Personal Roasting 2 2 (100%) 16.6 25.1 2 (100%)

2,3-Pentanedione Area Admin 2 2 (100%) 3.3 5.0 N/A

2,3-Pentanedione Area Bakery 2 2 (100%) 4.5 4.7 N/A

2,3-Pentanedione Area Café 4 4 (100%) 2.4 17.5 N/A

2,3-Pentanedione Area Green Bean Storage 2 1 (50%) <0.5 1.6 N/A

2,3-Pentanedione Area Grinding 2 2 (100%) 15.4 20.6 N/A 

2,3-Pentanedione Area Maintenance Shop 2 1 (50%) <0.3 1.4 N/A

2,3-Pentanedione Area Packaging 4 4 (100%) 9.4 38.0 N/A

2,3-Pentanedione Area QC Lab 2 2 (100%) 5.6 8.9 N/A

2,3-Pentanedione Area Roasted Bean Storage 4 4 (100%) 17.2 28.4 N/A

2,3-Pentanedione Area Roasting 2 2 (100%) 17.6 29.3 N/A

Appendix A: Tables
Page 26 Health Hazard Evaluation Report 2016-0141-3329

Analyte Sample 

Type Location N

Above 

LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Above 

REL N 

(%)

2,3-Pentanedione Area TRAINING CENTER 2 2 (100%) 5.5 8.3 N/A

2,3-Pentanedione Area WAREHOUSE 2 2 (100%) 6.6 9.7 N/A

2,3-Hexanedione Personal Bakery 2 2 (100%) 0.3 0.3 -

2,3-Hexanedione Personal Production Area 5 3 (60%) <0.2 1.3 -

2,3-Hexanedione Personal Production Office 4 0 (0%) <0.2 <0.3 -

2,3-Hexanedione Personal QC Lab 2 1 (50%) <0.2 0.3 -

2,3-Hexanedione Personal Roasting 2 1 (50%) <0.2 1.2 -

2,3-Hexanedione Area Admin 2 0 (0%) <0.2 <0.3 N/A

2,3-Hexanedione Area Bakery 2 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Café 4 1 (25%) <0.2 0.9 N/A

2,3-Hexanedione Area Green Bean Storage 2 0 (0%) <0.2 <0.4 N/A

2,3-Hexanedione Area Grinding 2 1 (50%) <0.2 0.6 N/A

2,3-Hexanedione Area Maintenance Shop 2 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Packaging 4 3 (75%) <0.2 1.4 N/A

2,3-Hexanedione Area QC Lab 2 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Roasted Bean Storage 4 2 (50%) <0.2 0.9 N/A

2,3-Hexanedione Area Roasting 2 1 (50%) <0.2 1.2 N/A

2,3-Hexanedione Area TRAINING CENTER 2 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area WAREHOUSE 2 0 (0%) <0.2 <0.2 N/A

Note: OSHA=Occupational Safety and Health Administration; NIOSH=National Institute for Occupational Safety 

and Health; N=number of samples; Above LOD N (%) = number and percentage of samples above the limit of 

detection (LOD); < indicates below the LOD; <= indicates less than or equal to the LOD; Above REL N=number of 

samples above the NIOSH recommended exposure limit (REL); ppb=parts per billion; N/A indicates that NIOSH 

RELs are specified for personal air samples, and cannot be directly applied to area air samples “-“ indicates there 

is currently no REL for 2,3-hexanedione.

Table A1 (cont.). OSHA Methods 1013/1016 full-shift personal and area air sampling results by 

location, January–February 2017.
Health Hazard Evaluation Report 2016-0141-3329 Page 27

Table A2. Summary of personal short-term task-based measurements, January-February 2017

Analyte Sample 

Type Task N Above LOD N (%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Mean 

(range) 

Sample 

Duration 

(minutes)

Diacetyl Personal Cleaning Roaster 2 2 (100%) 11.3 28.7 15

Diacetyl Personal Grind coffee beans 5 5 (100%) 53.2 66.9 13 (5-15)

Diacetyl Personal Package coffee 13 13 (100%) 14.0 56.0 15

Diacetyl Personal Roast coffee beans 12 12 (100%) 7.2 25.6 15

2,3-Pentanedione Personal Cleaning Roaster 2 2 (100%) 8.4 18.1 15

2,3-Pentanedione Personal Grind coffee beans 5 5 (100%) 32.3 53.8 13 (5-15)

2,3-Pentanedione Personal Package coffee 13 13 (100%) 12.1 46.6 15

2,3-Pentanedione Personal Roast coffee beans 12 12 (100%) 7.1 25.1 15

2,3-Hexanedione Personal Cleaning Roaster 2 0 (0%) <0.7 <0.7 15

2,3-Hexanedione Personal Grind coffee beans 5 4 (80%) <0.7 2.8 13 (5-15)

2,3-Hexanedione Personal Package coffee 13 11 (85%) <0.7 2.2 15

2,3-Hexanedione Personal Roast coffee beans 12 1 (8%) <0.7 0.9 15

Note: N=number of samples; % Above LOD N (%)=number and percentage of samples above limit of detection 

(LOD); < indicates below the LOD; <= indicates less than or equal to the LOD; Above STEL N (%)=number of 

samples above the NIOSH short-term exposure limit (STEL); ppb=parts per billion.
Page 28 Health Hazard Evaluation Report 2016-0141-3329 Table A3. Instantaneous evacuated canister method* air sampling results by source, NIOSH survey, January-February 2017 Task Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 23.8 16.6 <1.0 Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 40.9 35.1 1.5 Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 26.2 20.0 <1.1 Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 32.3 28.7 1.3 Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 30.1 28.0 1.1 Bagging at the matrix frac bagger; using vacuum to fill feed hopper from barrel; breathing zone over barrel when vacuuming; 75 percent medium and 25 percent dark Guatamalan 59.1 57.5 2.4 Bagging at weight right- using vacuum in plastic tub; whole bean 48.2 30.3 1.9 Bagging at weight right- using vacuum in plastic tub; whole bean 42.8 31.9 1.8 Bagging at weight right- using vacuum in plastic tub; whole bean 42.7 27.9 1.5 Bagging at weight right; at dispenser; fill 5 lb bags with whole bean; dark roast 42.9 30.0 1.7 Bagging at weight right; at dispenser; fill 5 lb bags with whole bean; medium roast 36.1 28.6 1.8 Bagging at weight right; at dispenser; fill 5 lb bags with whole bean; medium roast 58.9 50.6 3.3 Frac packaging; emptying frac bags back into ground coffee container 5.7 6.6 <1.0 Frac packaging; suck up ground coffee via tube 27.2 20.6 2.4 Frac packaging; suck up ground coffee via tube 30.4 30.1 1.9 Manual mixing of ground coffee inside metal container 148 94.7 4.1 Scooping whole beans into grinder 52.4 43.2 2.8 Working over cooling bin 24.9 22.9 1.3 Working over cooling bin 30.5 24.1 1.1 Note: ppb=parts per billion; < indicates below the limit of detection. *Sampling duration approximately 30 seconds; task-based air samples were collected by placing the inlet of the canister sampler in the employee’s personal breathing zone as he/she performed work task to mimic exposure
Health Hazard Evaluation Report 2016-0141-3329 Page 29 Table A4. Instantaneous evacuated canister method* air sampling results by source, NIOSH survey, January-February 2017 Task Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) Five inches above whole dark beans being scooped into grinder; decaf 91.5 44.1 2.3 Above bins in middle of off gas area; two bins high, 28 bins; 80 pounds per bin 71.3 53.2 4.0 At mouth of grinder nozzle into barrel; decaf 4746 1845 82.7 Directly over bag of medium roast; five pound bag 139 159 <9.4 Directly over bag of medium roast; five pound bag 344 468 20.2 Directly over cooling bin of dark French roast 31.7 18.9 2.8 First small grinder; into a bag of medium roast; directly above bag mouth 1473 1249 41.4 First small grinder; into a bag of medium roast; directly above bag mouth 9062 6897 270 In a bin of dark roast; 24 hours after roast; ready to be mixed into a blended coffee 63.9 31.4 1.7 In a bin of light/med roast; four hours after roasting 467 499 <9.6 In a bin of light/medium roast; four hours after roasting 122 131 <10.2 Note: ppb=parts per billion; < indicates below the limit of detection for the instrument used to detect 2,3-hexanedione. *Sampling duration approximately 30 seconds; source air samples were collected by placing the inlet of the canister sampler near roasted beans.
Page 30 Health Hazard Evaluation Report 2016-0141-3329 Table A5. Real-time air monitoring results for carbon monoxide (CO), carbon dioxide (CO2), temperature, and relative humidity (RH), NIOSH survey, January-February 2017 Relative Humidity Range verage) (A verage)(A Temperate Range °F Range verage) ppm (A CO Range verage) ppm (A eaork ArWGrinding 1.2-163.5 (6.5) 470-1219 (627.4) – – Packaging 2.1-35.8 (8.8) 271-968 (684.3) 66.1-77.1 (73.9) – Roasting 0.9-38.6 (7.29) 487-1231 (703.24) 77.4-88.3* (84.2) 13.2-22.7* (15.18) QC Lab 0.9-6.4 (1.9) 531-1280 (677.2) 66.7-81.1† (77.4) 17.8-32.3† (22.67) Bakery‡ 1.1-4.5 (1.9) 531-1059 (602.3) 66.7-81.1 (77.4) 17.8-32.3 (22.66) Note: NIOSH=National Institute for Occupational Safety and Health; ppm=parts per million; “–“Nothing recorded during the sampling period; *Roasting temperature or relative humidity was not recorded on 02/01/2017; †QC Lab temperature or relative humidity was not recorded on 01/31/2017; ‡Sampling only occurred on 02/01/2018 in the bakery
Health Hazard Evaluation Report 2016-0141-3329 Page 31

Table A6. Personal air sampling for carbon monoxide, NIOSH survey, January-February 2017

CO (ppm) CO (ppm) CO (ppm) Sample Location Job Title Minimum Maximum Average

Production Area Production Employee 0 467 7.16

Roasting Roaster 0 60 4.54

Production Area Production Employee 0 617 10.93

Quality Control Lab Coffee Quality Specialist 0 11 2.62

Production Area Production Employee 0 425 9.92

Roasting Roaster 0 55 7.70

Production Area Production Employee 2 836 11.68

Production Office Assistant Production Manager 0 304 8.20

Production Office Production Manager 0 8 0.93

Bakery Director of Kitchen Operations 0 18 1.15

Quality Control Lab Coffee Quality Specialist 0 20 2.67

Note: NIOSH=National Institute for Occupational Safety and Health; CO=carbon monoxide.

Table A7. Headspace analysis results* for bulk samples of roasted coffee beans, NIOSH survey, 

January-February 2017

Diacetyl 2,3-Pentanedione 2,3-Hexanedione Sample Type Bulk Sample Description (ppb) (ppb) (ppb)

 Coffee beans Light Ring of Fire 102 255 < 212

 Coffee beans Decaffeinated Cream City < 86 208 < 212

 Coffee beans Light El Salvador 323 500 < 212

 Coffee beans Dark Guatemala < 86 201 < 212

Note: NIOSH=National Institute for Occupational Safety and Health; ppb=parts per billion. < indicates that 

the sample was less than the limit of detection.

*The roasted coffee beans off-gassed for different amounts of time, and this could be responsible for some of the 

differences in headspace analysis results.
Page 32 Health Hazard Evaluation Report 2016-0141-3329 Table A8. Prevalence of reported symptoms, NIOSH medical survey, February 2017 Experienced in the last 4 weeks N = 8 Number (%) Experienced in the last 12 months N = 8 Number (%) Symptom Nose symptoms* 7 (88%) 5 (63%) Eye symptoms† 4 (50%) 3 (38%) Sinusitis or sinus problems 4 (50%) 2 (25%) Problem with ability to smell 2 (25%) - Phlegm on most days for 3 months 1 (12.5%) - Lower respiratory symptoms (reported at least one of the following) 2 (25%) 0 (0%) Breathing trouble 1 (13%) 1 (13%) Chest wheezing or whistling 2 (25%) 0 (0%) Awoke with chest tightness 0 (0%) 0 (0%) SOB on level ground or walking up a slight a hill 0 (0%) - Awoke with shortness of breath 0 (0%) 0 (0%) Asthma attack 0 (0%) 0 (0%) Usual cough 0 (0%) 0 (0%) Systemic symptoms(reported at least one of the following) 4 (50%) 0 (0%) Flu-like achiness or achy joints 4 (50%) 0 (0%) Fever or chills 0 (0%) 0 (0%) Unusual tiredness or fatigue 0 (0%) 0 (0%) Note: N=number of participants; SOB=shortness of breath; “-“= A four week question was not asked for the symptom. *Nose symptoms includes one or both of the following: 1) stuffy, itchy, or runny nose or 2) stinging, burning nose. †Eye symptoms includes one or both of the following: 1) watery, itchy eyes or 2) stinging, burning eyes.
Health Hazard Evaluation Report 2016-0141-3329 Page 33

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Keywords: NAICS 311920 (Coffee roasting), Wisconsin, diacetyl, 2,3-pentanedione, 

2,3-hexanedione, coffee, carbon monoxide, carbon dioxide, volatile organic compounds 

(VOCs).
Health Hazard Evaluation Report 2016-0141-3329 Page 43

The Health Hazard Evaluation Program investigates possible health hazards in the workplace 

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(6)). The Health Hazard Evaluation Program also provides, upon request, technical assistance 

to federal, state, and local agencies to investigate occupational health hazards and to prevent 

occupational disease or injury. Regulations guiding the Program can be found in Title 42, Code 

of Federal Regulations, Part 85; Requests for Health Hazard Evaluations (42 CPR Part 85).

Disclaimer 

The recommendations in this report are made on the basis of the findings at the workplace 

evaluated and may not be applicable to other workplaces.

Mention of any company or product in this report does not constitute endorsement by the 

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Citations to Web sites external to NIOSH do not constitute NIOSH endorsement of the 

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Acknowledgments

Desktop Publisher: Tia McClelland 

Data Analysis Support: Tia McClelland, Nicole Edwards, Kathleen Fedan, and Brian Tift

Laboratory Support: Dru Burns, Kyle Hatcher, Ryan LeBouf, Anand Ranpara

Site Visit Team Members: Randy Boylstein, Sandy White, Ethan Fechter-Leggett, Michael 

Beaty.

Availability of Report

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health department and the Occupational Safety and Health Administration Regional Office 

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All other Health Hazard Evaluation Reports may be found at http://www2a.cdc.gov/hhe/

search.asp.

Recommended citation for this report:

NIOSH [2018]. Health hazard evaluation report: Evaluation of exposure and 

respiratory health at a coffee roasting and packaging facility. By Boylstein 

RJ, McClelland TM, White SB. Morgantown, WV: U.S. Department of Health 

and Human Services, Centers for Disease Control and Prevention, National 

Institute for Occupational Safety and Health, NIOSH HHE Report No. 2016-

0141-3329.
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