Health Hazard Evaluation Report 2016-0005-3303 Page 1

Evaluation of exposures and respiratory 

health at a coffee roasting and packaging 

facility 

Report No. 2016-0005-3303

January 2018

Brie Hawley, MS, PhD

Laura Reynolds, MPH, BSN, RN

Randall J. Nett, MD, MPH

Stephen B. Martin, Jr., PhD, PE

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 2016-0005-3303

Contents

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

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

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

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

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

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

Methods ............................................... 7

Results ................................................ 12

Discussion .......................................... 16

Conclusions........................................ 21

Recommendations............................. 22

Appendix A: Tables............................ 26

References.......................................... 31

Acknowledgements........................... 41

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 2016-0005-3303 Page i

We evaluated respiratory 

health among employees and 

measured alpha-diketones 

(diacetyl, 2,3-pentanedione, and 

2,3-hexanedione), other volatile 

organic compounds, carbon 

monoxide, and carbon dioxide 

in the air at a coffee roasting and 

packaging facility. One employee in 

the production area of the facility 

had one full-shift exposure that 

exceeded the NIOSH recommended 

exposure limit for diacetyl. One of 

the 15-minute short-term exposure 

samples collected on employees 

grinding roasted coffee beans 

exceeded the NIOSH recommended 

short-term exposure limit for diacetyl. 

Air levels of carbon monoxide 

exceeded the NIOSH ceiling limit 

of 200 parts per million in the area 

near the main grinders. Nose and 

sinus symptoms were the most 

commonly reported symptoms. 

Some employees reported their 

symptoms were better away from 

work. One of five participants 

had abnormal spirometry. We 

recommend engineering controls 

to mitigate exposure to diacetyl, 

2,3-pentanedione, and carbon 

monoxide near the main grinders. 

We also recommend implementing 

administrative controls such as 

modification of work practices, 

training employees about workplace 

hazards, and instituting a medical 

monitoring program.

Highlights of this Evaluation

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

Health received a request from management at a coffee roasting and packaging facility. The 

request included concerns about the potential health effects from exposure to diacetyl during 

coffee roasting, grinding, and packaging.

What We Did

● We visited the coffee roasting and packaging 

facility in February and March 2017.

● We performed an industrial hygiene survey at 

the facility in February 2017.

● We collected full-shift (hours), task 

(minutes), and instantaneous (seconds) air 

samples to measure concentrations of alphadiketones. Specifically, we collected diacetyl, 

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

measurements on each day of our visit. 

● 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 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

● On full-shift sampling, one production 

employee was exposed to diacetyl 

concentrations above the National Institute for 

Occupational Safety and Health recommended 

exposure limit of 5 parts per billion. The 

highest concentration of diacetyl we measured 

as an average across a full-shift was 5.6 parts 

per billion.

● Levels of diacetyl and 2,3-pentanedione in the 

air during short-term sampling were higher 

for tasks involving grinding roasted coffee 
Page ii Health Hazard Evaluation Report 2016-0005-3303

(maximum 31.7 parts per billion).

● One of the three 15-minute samples collected on employees performing grinding 

of coffee beans exceeded the National Institute for Occupational Safety and Health 

recommended short-term exposure limit for diacetyl of 25 parts per billion.

● Carbon monoxide levels exceeded the National Institute for Occupational Safety and 

Health recommended ceiling limit of 200 parts per million in the area near the grinders. 

● All bulk samples of roasted coffee beans emitted diacetyl and 2,3-pentanedione.

● Nose and sinus symptoms were the most commonly reported symptoms. Some 

employees reported their symptoms were better away from work.

● One of five participants had abnormal spirometry.

● One of five participants had high exhaled nitric oxide, a marker of allergic airways 

inflammation.

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.

● Consult with a ventilation engineer to develop an overall engineering control plan to 

reduce airborne alpha-diketone concentrations. Verify that adequate fresh, outdoor air is 

being supplied by the existing rooftop AHU, and, if not, increase the amount of outdoor 

air consistently provided to the production space during periods of occupancy.

● Install a local exhaust ventilation system at the main grinders to capture diacetyl, 

2,3-pentanedione, and carbon monoxide emissions from the main grinders and 

packaging of ground coffee.

● Continue to cover bins of roasted beans to reduce emissions of alpha-diketones, carbon 

monoxide, and carbon dioxide into the air.

● Automate transfer of roasted beans, whenever possible, to minimize manual handling 

of roasted coffee beans.

● Conduct follow-up air sampling to verify that the modifications have been effective in 

reducing exposures to below the recommended exposure limits.

● Install a carbon monoxide monitor near the main grinders to alert employees if carbon 

monoxide levels exceed the National Institute for Occupational Safety and Health 

recommended ceiling limit of 200 parts per million.

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

use for protection against coffee dust exposure, such as when emptying burlap bags of 

green beans into the storage silos, cleaning the chaff out of the roaster exhaust system, 

emptying the chaff containers, or cleaning the green bean storage area. 

● Encourage employees to report new, worsening, or ongoing respiratory symptoms to 
Health Hazard Evaluation Report 2016-0005-3303 Page iii

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 it is installed.

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

storage bins. 

● Some employees may wish to use N-95 disposable filtering-facepiece respirators for 

some tasks, such as when emptying burlap bags of green beans into storage containers, 

cleaning the chaff out of the roaster exhaust system, emptying the chaff containers, or 

cleaning the green bean storage area.

● Participate in any personal air sampling offered by your employer.

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

provider 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 2016-0005-3303 Page v

Abbreviations

μg Microgram

°F degrees Fahrenheit

ACGIH® American Conference of Governmental Industrial Hygienists

AHU Air-handling unit

APF Assigned protection factor

AX Area of reactance

CFR Code of Federal Regulations

CO Carbon monoxide

CO2 Carbon dioxide

COPD Chronic obstructive pulmonary disease

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

FEV1 Forced expiratory volume in 1 second

Fres Resonant frequency

FVC Forced vital capacity

IDLH Immediately dangerous to life or health

IOS Impulse oscillometry

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

LOD Limit of detection

LOQ Limit of quantitation

LPM Liters per minute

mL Milliliter

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

R5 Resistance at 5 Hertz

R20 Resistance at 20 Hertz

REL Recommended exposure limit

STEL Short-term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

US United States
Page vi Health Hazard Evaluation Report 2016-0005-3303

VOC Volatile organic compound

X5 Reactance at 5 Hertz
Health Hazard Evaluation Report 2016-0005-3303 Page 1

Summary

In October 2015, the Health Hazard Evaluation Program of the National Institute for 

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

roasting and packaging facility regarding concerns about health issues related to exposure 

to diacetyl during coffee roasting, grinding, and packaging. During February 27–March 2, 

2017, we conducted an industrial hygiene survey, ventilation assessment, and medical survey 

at the facility. The industrial hygiene survey consisted of the collection of air samples and 

bulk samples of coffee for the analysis of diacetyl, 2,3-pentanedione, and 2,3-hexanedione. 

Continuous monitoring instruments were used to monitor total volatile organic compounds, 

carbon monoxide, carbon dioxide, temperature, and relative humidity in specific areas and 

during tasks. The medical survey consisted of a health questionnaire and breathing tests.

One of the three personal full-shift air samples exceeded the NIOSH recommended 

exposure limit for diacetyl of 5 parts per billion. The personal air sample that exceeded 

the recommended exposure limit for diacetyl was collected on an employee with primary 

job duties on the production floor. None of the personal full-shift air samples exceeded 

the NIOSH recommended exposure limit for 2,3-pentanedione. The highest partial-shift 

and task-based diacetyl and 2,3-pentanedione exposure measurements were observed on 

employees that ground coffee, or worked in the packaging area near the grinders. Areas with 

ground coffee present, specifically the two main grinders, had the highest levels of diacetyl, 

2,3-pentanedione, total volatile organic compounds, and carbon monoxide. We observed high 

instantaneous levels of carbon monoxide during grinding. Carbon monoxide levels measured 

on employees that ground coffee exceeded the NIOSH ceiling limit of 200 parts per million. 

Carbon dioxide levels were low throughout most of the facility.

Nose and sinus symptoms were the most commonly reported symptoms. Some employees 

reported their symptoms were better when away from work. One of the five participants 

had abnormal spirometry. We recommend a combination of engineering and administrative 

controls to minimize employee exposures. We also recommend a medical monitoring 

program 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 2016-0005-3303

Introduction

In October 2015, the Health Hazard Evaluation Program of the National Institute for 

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

roasting and packaging facility. The request stated concerns about possible health issues 

related to exposure to diacetyl during coffee roasting and packaging. During February 27–

March 2, 2017, we visited the facility to learn more about coffee processing and to conduct 

industrial hygiene and medical surveys. We collected area and personal breathing zone air 

samples for volatile organic compounds (VOCs), including diacetyl, 2,3-pentanedione, and 

2,3-hexanedione. We also monitored and recorded carbon monoxide (CO), carbon dioxide 

(CO2), and total volatile organic compounds (VOCs).

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 less than 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 5th percentile) 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 
Health Hazard Evaluation Report 2016-0005-3303 Page 3

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

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

time or at lower concentrations 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. CO and CO2 are also produced as a result 

of reactions that take place during coffee roasting and are released during and after roasting 

and grinding by a process called off-gassing [Anderson et al. 2003]. High exposures to CO 

and CO2 can cause headache, dizziness, fatigue, nausea, confusion, 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 utilize 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)

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 2016]. 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) TLVs and NIOSH RELs.

American Conference of Governmental Industrial Hygienists (ACGIH) 

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 

called threshold limit values (TLVs®) [ACGIH 2017a]. 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 
Page 4 Health Hazard Evaluation Report 2016-0005-3303

workday of a 40-hour 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 

2017a]. 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 2017b]. 

National Institute for Occupational Safety and Health (NIOSH)

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]. NIOSH also provides 

recommended 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 recommended 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 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]. 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. 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 2016-0005-3303 Page 5

Table 1. Exposure limits for compounds sampled during the NIOSH survey, February 

2017.

OSHA* ACGIH NIOSH

Compound PEL TLV STEL REL STEL IDLH

Diacetyl - 10 ppb 20 ppb 5 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 Hygienist; 

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; mg/m3

=milligram per cubic meter; 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 may include 

cough, shortness of breath on exertion, and 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]. 

Obliterative bronchiolitis 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 concerning (range: 4.3 ppb to 166 ppb diacetyl; <5.2 ppb to 199 ppb 

2,3-pentanedione) 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 for off-gassing, on a mezzanine above the grinding/

packaging process [Duling et al. 2016]. At the time of the previous 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 2016-0005-3303

Work-related Asthma

Work-related asthma refers to asthma 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 caused by sensitizers, which cause disease through immune (allergic) 

mechanisms, and asthma caused by 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

In March 2017, the coffee roasting and packaging facility had five full-time employees. The 

coffee company also had a café located off-site. At the coffee roasting and packaging facility, 

the production area was approximately 1,000 square feet. Roughly 280 pounds to 360 pounds 

of coffee were roasted and packaged per day, and approximately one-third of the coffee 

produced was ground coffee. The facility received green coffee beans in burlap bags. Green 

beans were stored in burlap bags and storage containers along the wall by the roasting and 

packaging area. 

To prepare a batch for roasting, a roaster operator poured, weighed, and transferred the 

green coffee beans into the roaster. The roaster was a Probat roaster capable of roasting 26.4 

pounds of coffee per batch. When ready, the roaster operator dropped the green beans into 

the roaster. The beans were heated to a specific temperature and for a specific time period for 

the desired roast. Time and temperature varied between different types of roasts. On average, 

roasts lasted 12 minutes to 15 minutes. Occasionally, the roaster operator would pull a small 

sample of beans from the roaster to check the color of the beans. At the end of each cycle, the 

roaster operator emptied the roasted beans into a cooling bin where they were agitated by a 

rotating arm. The cooling bin at the roaster utilized a downdraft exhaust system that pulled 

air downward past the roasted beans to accelerate cooling. The downdraft system exhausted 

through the roaster and then to the outside through a ventilation duct. The roaster operator 

monitored the roasting equipment throughout the roasting and cooling process. After cooling, 

the roasted beans were dispensed from the cooling bin of the roaster into transfer bins that 

were used by the roaster operator to transfer the roasted beans to the destoner. After being 

processed through the destoner, the beans were then ready for additional processing in the 

packaging area. 
Health Hazard Evaluation Report 2016-0005-3303 Page 7

In the packaging area, orders were completed by weighing and packaging whole bean or 

ground coffee. All bags were manually weighed and packaged into compostable paper bags 

for bulk coffee or 12 oz bags equipped with one-way valves for off-gassing. For ground 

coffee, an employee weighed the whole beans before manually emptying the coffee beans 

into a grinder. Two grinders were used to grind coffee. One grinder could grind up to five 

pounds of coffee, and the other could grind up to three pounds of coffee. After packaging, 

bags of coffee were stored on open shelves and racks adjacent to the packaging area. 

Every three months, the roasters were cleaned; accumulated chaff was removed and the 

exhaust lines from the roasters were cleaned. 

Personal Protective Equipment 

Employees wore gloves and hairnets while working in the coffee production area. Roasting 

employees who worked with green coffee beans voluntarily wore N95 filtering facepiece 

respirators.

Methods

We visited the coffee roasting and packaging facility during February 27–March 2, 2017. 

We held an opening meeting with management and an employee representative, collected 

air samples, performed a ventilation assessment, and conducted a medical survey. At the 

conclusion of our site visit, we held a closing meeting with management and 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;

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

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

3. Measure levels of CO and CO2 in different areas of the facility;

4. Assess the ventilation systems and the ventilation systems’ effect on exposure levels;

5. Determine if employees had nose, eye, sinus, lower respiratory, and systemic 

symptoms and if those symptoms were work-related.

6. Determine if employees had abnormal lung function tests.

Industrial Hygiene Survey

Sampling Times for Alpha-Diketones 

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

and processes that contributed to worker exposure to alpha-diketones. For diacetyl, 

2,3-pentanedione, and 2,3-hexanedione, air samples were collected over seconds, minutes, 

and hours. Samples collected over hours can help determine average concentrations that 

can be compared with the NIOSH RELs for diacetyl and 2,3-pentanedione. These average 
Page 8 Health Hazard Evaluation Report 2016-0005-3303

concentrations might not tell us about short-term peak exposures that could be relevant 

to respiratory health, particularly for tasks repeated multiple times per day. Therefore, 

during particular tasks, we collected air samples over several minutes. We also conducted 

instantaneous sampling over seconds to help identify point sources of alpha-diketones. 

Employees that 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 (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 our industrial hygiene survey. 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 time-weighted average (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. Some employees had shifts that lasted only two to three hours each 

day. For those employees, we refer to their time-weighted averages as partial-shift samples. 

We also collected 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 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 measure above 

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

The limit of quantitation (LOQ) is the lowest mass that can be reported with precision; we 

have a greater confidence in the reported result if it is above the LOQ. The LODs were 0.01 

micrograms per sample (μg/sample) for diacetyl, 2,3-pentanedione, and 2,3-hexanedione. 

These equate to 0.3 parts per billion (ppb) for diacetyl, 0.2 ppb for 2,3-pentanedione, and 

0.2 ppb for 2,3-hexanedione for a typical full-shift TWA air sample but will vary depending 

on the volume of air collected during the sampling period. The LODs for task samples 
Health Hazard Evaluation Report 2016-0005-3303 Page 9

are generally higher than typical LOD values for full-shift samples since the air volumes 

collected during task samples are lower. When the values presented in the report are from 

samples below the LOD they are denoted by a “<” symbol. The LOQs equate to 1.1 ppb for 

diacetyl, 0.90 ppb for 2,3-pentanedione, and 0.79 ppb for 2,3-hexanedione for a typical fullshift air sample.

Air Sampling and Analysis Using Evacuated Canisters

We collected full-shift, time-weighted average area air samples and instantaneous task-based 

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 control 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, and 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. The LODs were 0.78 ppb for diacetyl, 1.08 ppb for 

2,3-pentanedione, and 1.92 ppb for 2,3-hexanedione based on a three-times dilution factor. 

However, LODs are dependent on the pressure inside each canister after the samples have 

been collected, and they may 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 (Continuous) Air Sampling

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

to measure concentrations of total VOCs 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 total VOCs. Areas where higher concentrations of total VOCs are measured help 
Page 10 Health Hazard Evaluation Report 2016-0005-3303

indicate areas where sampling to characterize specific exposures to alpha-diketones may be 

necessary. 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 took air flow measurements in the production space using a Model EBT731 Balometer 

Air Balancing Instrument (Alnor Products, TSI Incorporated, Shoreview, MN).We were 

unable to physically assess the single rooftop-mounted air-handling unit (AHU) during our 

visit, as there was no readily-available means to access the roof of the facility. 

NIOSH Medical Survey

Participants 

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

during March 1–2, 2017. This facility also participated in a program in which adults with 

disabilities work for two hours per day. In this report, those employees will be referred to 

as ‘day workers’. Because the work program is voluntary and day workers chose their work 

activity daily, different day workers can work at the facility each day. Because of the day 

workers’ scheduling constraints, we could only invite four day workers to participate in the 

medical survey. Participation was voluntary and written informed consent was obtained from 

each participant before conducting the survey. The survey included, in the order performed, 

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

oscillometry, spirometry, and if indicated, the administration of bronchodilator with repeat 

impulse oscillometry and spirometry. Day workers were excluded from analyses as they did 

not complete all medical testing. 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 the three 

measurements or calculations: 1) forced vital capacity (FVC), (the total amount of air the 
Health Hazard Evaluation Report 2016-0005-3303 Page 11

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 4) 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 

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) 

resonance 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 references 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 
Page 12 Health Hazard Evaluation Report 2016-0005-3303

there was evidence of frequency dependence 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.

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 9.3 (SAS 

Institute, Cary, NC). We created summary statistics by work area, 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 performed analyses using Excel (Microsoft®, Redmond, WA) and SAS version 9.3 (SAS 

Institute, Cary, NC). We calculated frequencies and compared prevalences of symptoms and 

diagnoses among participants. The small number of participants limited the conclusions that 

can be drawn from these analyses. 

Results

All results tables are located in Appendix A.

Industrial Hygiene Survey

Personal and Area Full-shift Air Sampling Results 

Personal and area full-shift air sampling results for diacetyl, 2,3-pentanedione, and 

2,3-hexanedione using OSHA Method 1013/1016 can be seen in Table A1. On the days of 

our visit, only two employees worked for more than six-hours. One of the two employees 

worked more than six-hours on both days for a total of three full-shift sample measurements. 

We collected three personal and 25 area full-shift air samples. One personal air sample 

collected on an employee with primary job duties in the grinding and packaging area was 

above the NIOSH REL for diacetyl of 5 ppb, with a concentration of 5.6 ppb. No personal air 

samples were above the NIOSH REL for 2,3-pentanedione of 9.3 ppb. All personal and area 

samples were below the LOD for 2,3-hexanedione.

The area between the two grinders had the highest full-shift average area levels for diacetyl 

(18.5 ppb) and 2,3-pentanedione (9.0 ppb). One area full-shift air sample (collected in the 
Health Hazard Evaluation Report 2016-0005-3303 Page 13

area between the two grinders) was above the NIOSH REL for diacetyl. All other areas, 

including the area samples collected at the offsite café, were below the NIOSH REL for 

diacetyl and 2,3-pentanedione. Because area air samples are not personal air samples 

collected directly on an employee, the NIOSH RELs are not directly applicable to the results 

for exposure monitoring purposes. However, area air samples can highlight areas with higher 

exposure risk, and the RELs can be used as points of reference. 

Personal Partial-Shift Air Sampling Results

Personal air sampling results collected on employees who worked no more than three 

hours per shift can be seen in Table A2. We collected eight personal partial-shift samples 

using OSHA Method 1013/1016. Shift and sample duration lasted from 105 minutes to 180 

minutes. Levels of diacetyl and 2,3-pentanedione were higher on employees performing 

duties in the grinding area, with a maximum diacetyl concentration of 8.3 ppb and maximum 

2,3-pentanedione concentration of 5.2 ppb. We note that the NIOSH RELs for diacetyl and 

2,3-pentanedione are provided as TWA concentrations over an 8-hour work shift during a 40-

hour workweek. Because partial-shift samples were collected on employees who worked less 

than 20 hours a week and no more than four hours per day, they cannot be directly compared 

to the NIOSH RELs. All partial-shift samples were below the LOD for 2,3-hexanedione.

Task-Based Air Sampling Results

Personal task air concentration results can be seen in Table A3. We collected 19 personal 

task air samples using OSHA Method 1013/1016. Task sampling duration ranged from 13 

minutes to 23 minutes, with a median of 15 minutes. We collected personal task air samples 

while employees roasted coffee (n = 11), ground coffee (n = 3), and packaged coffee (n 

= 5). The highest exposures to diacetyl (31.8 ppb) and 2,3-pentanedione (19.5 ppb) were 

measured while an employee was grinding coffee (Table A3). For task samples collected 

while employees packaged coffee, the highest exposures were 11.7 ppb diacetyl and 6.2 ppb 

2,3-pentanedione. The highest exposures to diacetyl and 2,3-pentanedione while employees 

roasted coffee were 1.5 ppb and 0.9 ppb, respectively. 

One of the three 15-minute samples collected while employees ground coffee exceeded 

the NIOSH STEL of 25 ppb for diacetyl (31.8 ppb). None of the 15-minute samples (n=3) 

exceeded the NIOSH STEL of 31 ppb for 2,3-pentanedione.

We collected 29 personal samples near the breathing zone of employees using instantaneous 

canisters (Table A4). Levels of diacetyl and 2,3-pentanedione observed in the breathing 

zone of employees using instantaneous canisters were lower than the levels described above. 

Instantaneous samples taken at the breathing zone of employees while they ground coffee 

were 2.6 ppb to 11.9 ppb for diacetyl, and 1.7 ppb to 6.1 ppb for 2,3-pentanedione. Breathing 

zone samples taken while an employee cleaned chaff out of the roaster exhaust lines 

ranged from 7.0 ppb to 12.1 ppb for diacetyl and 3.6 ppb to 6.4 ppb for 2,3-pentanedione. 

Instantaneous samples taken at the breathing zone while employees handled roasted beans 

ranged from less than 0.5 ppb to 7.2 ppb for diacetyl and less than 0.6 ppb to 4.1 ppb for 

2,3-pentanedione. Samples collected while an employee dumped roasted beans from the 

roaster into the cooling bins ranged from 0.6 ppb to 1.1 ppb for diacetyl and less than 0.8 ppb 
Page 14 Health Hazard Evaluation Report 2016-0005-3303

to 1.0 ppb for 2,3-pentanedione. 

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

Organic Compounds (VOCs)

A summary of the real-time CO, CO2, temperature, RH, and total VOC area monitoring 

results can be seen in Table A5. Levels of CO2 and CO were consistent between the two 

days of our survey. Levels of CO2 and CO measured at the roaster ranged from 433 ppm to 

840 ppm for CO2 and <0.1 ppm to 12.1 ppm for CO. Total VOC measurements at the roaster 

ranged from 0 ppb to 493 ppb, with an average of 193 ppb. Levels of CO2 and CO measured 

at the grinder ranged from 430 ppm to 1,260 ppm for CO2 and <0.1 ppm to 176.4 ppm for 

CO. Total VOC measurements at the grinders ranged from 0 ppb to 11,604 ppb. Levels of 

CO2 and CO measured at the packaging weigh station ranged from 476 ppm to 1073 ppm for 

CO2 and 0.5 ppm to 16.0 ppm for CO.

A summary of continuous, real-time, personal measurements of CO can be seen in Table 

A6. TWA personal CO measurements ranged from 0.2 ppm to 20.9 ppm and were below 

the NIOSH REL of 35 ppm for CO exposure. The highest CO levels were observed on 

production employees while they ground coffee. Levels of CO near an employee’s breathing 

zone were as high as 301 ppm while an employee was grinding coffee; it exceeded the 

NIOSH recommended ceiling limit of 200 ppm for CO. 

Ventilation Assessment 

The production space (including the break room, production office, and storage area) was 

partitioned with partial walls and was served by a single air-handling unit mounted on the 

roof of the facility. Access to the roof was not readily available during our visit, so we were 

unable to visually inspect or document the make and model of the unit. 

The AHU provided supply air flow to the production space through seven 2 feet × 2 feet 

supply vents in the ceiling of the production space. An eighth 2 feet × 2 feet supply vent was 

present in the ceiling of the production office. Three 2 feet × 2 feet ceiling mounted return 

grilles fed return air back to the AHU; one in the packaging area and two directly beside each 

other near the roaster. The AHU was supplying about 2,600 cubic feet per minute of supply 

air too the space, including the 200 cubic feet per minute supplied to the production office. 

Since we were unable to access the AHU, we could not verify whether any fresh, outdoor air 

was being supplied to the occupied space during our visit.

In addition to any potential fresh, outdoor air supplied by the rooftop AHU, there was a large 

passive makeup air opening in the west side of the production space, near the green bean 

storage area, that allowed fresh air into the space, when necessary. The amount of fresh air 

brought into the space through this opening is dependent on the outdoor weather conditions, 

other windows or doors being opened or closed, and, most importantly, the various operating 

modes of the roaster during a complete roasting cycle and each mode’s individual air flow 

requirements. 
Health Hazard Evaluation Report 2016-0005-3303 Page 15

Medical Survey 

Demographics

Five (100%) full-time employees present during March 1–2, 2017, participated in the medical 

survey, including two café employees. Three (60%) participants were male, five (100%) were 

white, and the median age was 32 years (range: 27–36 years). Median tenure at the facility 

was 3.4 years (range: 1.6–5.1 years). Three (60%) participants were former smokers.

Four (80%) participants reported spending time in the production area of the facility during 

the work week. Of the four participants, all reported grinding coffee beans, moving roasted 

beans or ground coffee, and cleaning production machines. Three (75%) participants worked 

with green beans and worked where finished goods were stored. Two (50%) participants 

roasted coffee beans.

Three (60%) participants worked in the café and reported roasting and grinding coffee beans 

in the café. Two (67%) participants reported brewing coffee and using liquid flavorings.

Symptoms and Self-Reported Diagnoses

The prevalences of symptoms over both the last 12 months and four weeks reported at the 

time of the survey are listed in Table A7. Nose and sinus symptoms were the most commonly 

reported symptoms over the past 12 months (n=5, 100%) and four weeks (n=4, 80%). Two 

participants reported their sinus symptoms were better when away from work, and three 

participants reported their nose symptoms were aggravated at work.

Three (60%) participants reported one or more lower respiratory symptoms in the past 12 

months: wheezing or whistling in chest, breathing trouble, or shortness of breath on level 

ground or walking up a slight hill. Two participants reported lower respiratory symptoms 

in the four weeks before the medical survey. Four (80%) participants reported at least one 

or more systemic symptoms in the last 12 months: flu-like achiness or achy joints, fever or 

chills, or unusual tiredness or fatigue. Three participants reported having one or more of 

these symptoms in the last four weeks.

Participants reported a history of nasal allergies (n=2), eczema (n=1), and asthma (n=1). 

One participant reported a nasal allergy diagnosis after being hired at the facility. The other 

diagnoses were made before hire. No participants reported a diagnosis of chronic bronchitis, 

bronchiolitis obliterans, interstitial lung disease, hypersensitivity pneumonitis, chemical 

pneumonitis, sarcoidosis, heart disease, or vocal cord dysfunction. 

Medical Tests

One spirometry test was interpreted as having an obstructive pattern. One oscillometry test 

was interpreted as consistent with a large airways abnormality, and one was interpreted as 

consistent with a small and large airways abnormality. One exhaled nitric oxide test was 

interpreted as elevated. 
Page 16 Health Hazard Evaluation Report 2016-0005-3303

Discussion 

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 areas 

where coffee was ground between the two main grinders. Diacetyl, 2,3-pentanedione, 

2,3-hexanedione, other VOCs, and other compounds such as CO2 and CO 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]. 

Alpha-Diketones 

Personal Air Sampling 

One personal full-shift air sample taken inside the facility using standard OSHA methods 

was above the NIOSH REL for diacetyl. The highest personal full-shift diacetyl air sample 

(5.6 ppb) was collected on the production manager who had various duties in the production 

area. No personal air samples were above the NIOSH REL for 2,3-pentanedione. The highest 

partial-shift sample (8.2 ppb diacetyl and 5.2 ppb 2,3-pentanedione) was collected for 105 

minutes on an employee with grinding duties. We note NIOSH RELs are intended to be 

directly compared with personal measurements that approximate an 8-hour TWA as part of a 

40-hour workweek; therefore, the partial-shift samples that exceed a NIOSH REL are only an 

indication of potential personal exposures if that employee were to perform their job duties 

full-time.

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 (Table 5-27) [NIOSH 2016], after a 45-year working lifetime 

exposure to 5 ppb (a concentration slightly lower than the highest concentration measured 

at this facility), NIOSH estimated less than 1 in 1,000 workers would develop reduced 

lung function (FEV1 below the 5th percentile). NIOSH predicted that around 1 in 10,000 

workers exposed to diacetyl at 5 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 10 ppb (a 

concentration higher than the highest concentration measured at this facility), NIOSH 

estimated that less than 2 in 1,000 workers would develop reduced lung function (FEV1

below the 5th percentile). NIOSH predicted that 2 in 10,000 workers exposed to diacetyl at 

10 ppb would develop more severe lung function reduction. The effects of a working lifetime 

exposure at 5.6 ppb is close to 5 ppb. NIOSH recommends keeping diacetyl concentrations 

below 5 ppb because at this level, the risk of reduced lung function after a working lifetime 

of exposure is below 1 in 1000 workers. NIOSH recommends taking steps to reduce diacetyl 

exposures to below the REL of 5 ppb whenever possible.

Area Air Sampling 

One area sample collected in the area between the two main grinders had air levels (18.5 ppb) 
Health Hazard Evaluation Report 2016-0005-3303 Page 17

that exceeded the NIOSH REL for diacetyl. Areas near the two main grinders had the highest 

diacetyl (18.5 ppb) and 2,3-pentanedione (9.0 ppb) air levels. All other areas, including 

the area samples collected at the offsite café, were below the NIOSH REL for diacetyl 

and 2,3-pentanedione. 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. 

Task-Based Exposures

Coffee processing involves multiple tasks that may 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). Since 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 were only 

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

sampled by task, with varying durations, to understand which tasks may 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. The highest exposures to diacetyl (31.8 

ppb) and 2,3-pentanedione (19.5 ppb) were measured while an employee ground coffee 

(Table A2). One fifteen-minute sample collected while an employee ground coffee exceeded 

the NIOSH STEL of 25 ppb for diacetyl. No 15-minute samples exceeded the NIOSH STEL 

of 31 ppb for 2,3-pentanedione. The greater surface area for off-gassing that is produced 

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

Task-based air samples for roasting and packaging were lower. The highest exposures to 

diacetyl and 2,3-pentanedione while employees roasted coffee were 1.5 ppb and 0.9 ppb, 

respectively. Diacetyl and 2,3-pentanedione concentrations while employees packaged 

coffee were as high as 11.7 ppb and 6.2 ppb, respectively. All 15-minute samples collected 

while employees roasted or packaged coffee were below the NIOSH STEL for diacetyl and 

2,3-pentanedione.

Overall, instantaneous breathing zone samples were low. The highest instantaneous sample 

for diacetyl (12.1 ppb), and 2,3-pentanedione (6.4 ppb) was collected in the breathing zone 

of an employee while s/he cleaned chaff out of the roaster exhaust lines. The second highest 

instantaneous sample for diacetyl (11.9 ppb) and 2,3-pentanedione (6.1 ppb) were collected 

near the breathing zone of an employee while they ground coffee. Instantaneous samples of 

diacetyl and 2,3-pentanedione taken while employees were handling roasted whole beans 

were lower. The highest breathing zone sample taken while an employee dumped roasted 

beans from the roaster into the cooling bin had a diacetyl concentration of 1.1 ppb and a 

2,3-pentanedione concentration of 1.0 ppb. Instantaneous samples collected at the breathing 

zone of an employee while s/he scooped roasted whole beans onto the scale and then into a 

package ranged from 5.9 to 7.2 ppb for diacetyl and 3.3 ppb to 4.1 ppb for 2,3-pentanedione.
Page 18 Health Hazard Evaluation Report 2016-0005-3303

Real-time Sampling for CO, CO2, and VOCs

Our real-time monitoring found that the highest overall levels of total CO, CO2, and VOCs 

were observed at the grinders when they were in use. The average daily CO2 concentrations 

observed at the main grinders were 566 ppm on day 1 and 483 ppm on day 2, with a 

maximum of 1260 ppm, and were below the NIOSH REL (5,000 ppm) and OSHA PEL 

(5,000 ppm). Lower emissions were observed at the packaging weigh station and roasters.

None of the personal TWA levels of CO exceeded the NIOSH REL (35 ppm) or OSHA PEL 

(50 ppm). However, we noted two peak exposures that exceeded the NIOSH ceiling limit for 

CO of 200 ppm while an employee ground coffee. The NIOSH ceiling limit should not be 

exceeded at any time. 

Ventilation

Local exhaust ventilation

Local exhaust ventilation systems capture contaminants where they are generated and 

exhaust them before inhalation by employees occurs. Local exhaust ventilation systems 

generally consist of hoods or enclosures, duct work, or fans. Depending on the contaminant 

and whether air is recirculated, filters or other air cleaning technologies can be incorporated. 

When properly designed local exhaust ventilation systems are installed, overall workplace 

exposure levels can be reduced by removing contaminants at the source. Higher 

concentrations of alpha-diketones were measured near the grinders. Local exhaust ventilation 

installed near the grinders can be used to reduce employee exposures during grinding tasks, 

as well as reduce overall alpha-diketone concentrations in the production space. 

General exhaust or dilution ventilation

In an ideal environment, good general ventilation provides fresh air into the space and 

removes contaminated air. General exhaust ventilation allows contaminants to be emitted into 

the workplace and then dilutes the concentration of the contaminant to acceptable levels. This 

is generally done by providing fresh outdoor air (or recirculated, filtered air) to the space to 

provide dilution. 

During the February 2017 survey, we were unable to determine if fresh, outdoor air was 

supplied to the production space by the rooftop AHU. However, it was clear that outdoor 

air could enter the facility via inconsistent passive air transfer through the opening on the 

east wall. Passive air transfer is largely dependent on weather conditions and operating 

parameters of the roasters. An adequate supply of outdoor air, typically delivered through 

the heating, ventilation, and air-conditioning system, is necessary in any occupied spaces 

to dilute pollutants that are released by equipment, processes, products, and people. If the 

amount of outdoor air supplied to the space is low, increasing the outdoor air flow will 

provide more dilution and removal of airborne contaminants from the space. Consistently 

supplying the production space with appropriate outdoor air may not bring all personal 

exposures to diacetyl and 2,3-pentanedione below the NIOSH RELs, but it is a relatively 

easy engineering control to implement. The existing AHU is likely capable of providing 

adequate outdoor air flows, so only minor adjustments (if any) to the operating controls 

may be necessary. Providing more outdoor air flow will enhance dilution and removal of 
Health Hazard Evaluation Report 2016-0005-3303 Page 19

contaminants, but there will be additional energy costs associated with heating and cooling 

that outside air for much of the year. Those decisions should be made as part of an overall 

plan to improve engineering controls at the facility. A ventilation system expert can help meet 

all ventilation requirements in the production space and other areas of the building occupied 

by employees.

Additional air sampling should be conducted if there are changes in production processes, 

controls, or work practices that potentially change exposure conditions within the workplace.

Medical Survey

Overall, nose and sinus symptoms were the most commonly reported. Some employees 

reported their symptoms were aggravated by work. Coffee dust is an organic dust known 

to cause respiratory symptoms [Zuskin et al. 1993; Sakwari et al. 2013]. 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 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].

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

are sometimes associated with lower respiratory symptoms and asthma and can 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. Three of the five participants 

reported lower respiratory symptoms, and all five reported upper respiratory symptoms. 

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 might 

be to make N-95 disposable filtering-face piece respirators available for voluntary use when 

emptying burlap bags of green coffee beans into storage containers or cleaning the green 

bean storage area.

Three (60%) participants reported lower respiratory symptoms in the 12 months before the 

survey. Of these three employees, two reported the workplace aggravated their symptoms. 

Lower respiratory symptoms caused by diseases such as asthma often improve when away 

from exposures that trigger symptoms while symptoms caused by 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 that 

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 
Page 20 Health Hazard Evaluation Report 2016-0005-3303

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]. 

Two workers had abnormal impulse ocillometry results. One worker had a large airways 

abnormality and one had both a small and large airways abnormality. Spirometry and impulse 

oscillometry measure different things. Spirometry assesses airflow and is the breathing test 

typically used to screen for flavoring-related lung disease. Impulse oscillometry accesses the 

airways response to a sound or pressure wave and has not commonly been used to screen 

for flavoring-related lung disease. 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 may be useful as an 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 Assumpcão 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]. 

The respiratory symptoms reported and breathing test abnormalities identified during the 

survey are not specific to a particular respiratory problem or disease. They could be related to 

workplace exposures or to other factors. Indeed, some employees had respiratory diagnoses 

that preceded employment at this facility. 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 work-relatedness, 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 detected 

employee exposures to diacetyl that exceeded the NIOSH REL. All production employees 
Health Hazard Evaluation Report 2016-0005-3303 Page 21

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) should 

participate in the workplace medical monitoring program. A medical monitoring program 

is a means of early identification of employees who may 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 workrelated 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 exceeded 

the NIOSH REL and STEL for diacetyl. One of the 3 personal full-shift air samples was 

above the NIOSH REL for diacetyl of 5 ppb. The only full-shift air sample above the NIOSH 

REL was collected on an employee with primary job duties on the production floor. High 

task-based diacetyl exposure measurements were observed on employees that ground coffee. 

Areas with ground coffee present, specifically between the two main grinders, consistently 

had the highest levels of diacetyl, 2,3-pentanedione, total VOCs, and CO. CO2 levels were 

low throughout most of the facility. However, CO levels measured on employees grinding 

coffee exceeded the NIOSH ceiling limit of 200 ppm.

We were unable to visually assess the rooftop AHU or measure the amount of fresh, outdoor 

air supplied to the space by the ventilation system. Although there is some passive air 

transfer through the opening in the east wall of the facility, if the amount of outdoor air 

supplied to the space is low, increasing the outdoor air flow will provide more dilution and 

removal of airborne contaminants from the space. Consistently supplying the production 

space with appropriate outdoor air may still not bring all personal exposures to diacetyl and 

2,3-pentanedoine below the NIOSH RELs. Regardless, working with a ventilation engineer 

to optimize outdoor air delivery is a relatively inexpensive, easy place to start engineering 

control improvements, as the existing AHU is likely capable of providing more outdoor air 

flows with only minor adjustments. Additionally, installing a local exhaust ventilation system 

around the grinders to immediately remove alpha-diketones produced during that operation 

could further reduce overall concentrations of alpha-diketones in the production space.

Overall, nose and sinus symptoms were the most commonly reported symptoms over the last 

12 months and four weeks. Some employees reported their symptoms were better away from 

work. These respiratory symptoms reported and breathing test abnormalities identified during 

the survey are not specific to a particular respiratory problem or disease and could be related 

to workplace exposures or to other factors. 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 work-relatedness, such as health measures by job title or task.
Page 22 Health Hazard Evaluation Report 2016-0005-3303

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. We encourage this coffee processing facility to 

use a labor-management health and safety committee or working group to discuss our 

recommendations and develop an action plan. 

Engineering Controls

Engineering controls reduce employees’ exposures by removing hazards 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 develop an overall engineering control plan to 

reduce airborne alpha-diketone concentrations. Verify that adequate fresh, outdoor 

air is being supplied by the existing rooftop AHU, and, if not, increase the amount of 

outdoor air consistently provided to the production space during periods of occupancy.

2. Install local exhaust ventilation at the grinders to capture contaminants generated 

during grinding tasks, before they can spread throughout the rest of the production 

area. 

3. After engineering controls have been installed at the main grinders, 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 can fluctuate from day to day 

based on production schedules, we recommend personal air sampling for diacetyl and 

2,3-pentanedione over multiple days. 

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 that policies and procedures are followed consistently.

1. Install a CO monitor and alarm near the main grinders 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. Whenever possible, employees should avoid spending time in the immediate area 

where coffee is being ground and where ground coffee is being packaged.

3. Cover bins of roasted beans to aid in reducing the overall emission of alpha-diketones 
Health Hazard Evaluation Report 2016-0005-3303 Page 23

and other chemicals (e.g., CO, CO2) into the workplace.

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

production tasks that require employees to place their heads directly above or inside 

the roasted bean bins. 

5. Continue to periodically clean the roaster’s exhaust according to manufacturer 

instructions to remove chaff build up to reduce a fire hazard and to improve the 

efficiency, energy usage, and roaster performance.

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

CO, CO2, 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. 

7. 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 personal protective equipment in the form of respiratory protection in 

controlling respiratory exposures depends on avoiding breakdowns in implementation that 

result in insufficient protection. 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 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 follow-up air sampling after engineering controls have been 

installed indicates levels of diacetyl and 2,3-pentanedione above their respective 

NIOSH RELs and STELs, we recommend respiratory protection be used during tasks 

with elevated exposures. To reduce exposures to alpha-diketones, NIOSH-certified 

respirators should be fitted with organic vapor cartridges. The choice of respirator 

should be guided by personal exposure sampling for diacetyl and 2,3-pentanedione 

(NIOSH 2004). Respirators have assigned protection factors (APFs). APF refers to 

the highest level of protection a properly selected respirator can provide. For instance, 

air-purifying half-face respirators have an assigned protection factor (APF) of 10, 

and air-purifying full-face respirators have an APF of 50. Also, there are powered-air 
Page 24 Health Hazard Evaluation Report 2016-0005-3303

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. 

2. Continue to make N95 disposable filtering-face piece respirators available for 

voluntary use for protection against green or roasted coffee dust exposure such 

as when emptying burlap bags of green beans into the storage silos, cleaning the 

roaster exhaust system of chaff, emptying the chaff containers, or cleaning the green 

bean storage area. N95 respirators should be available in various sizes, and each 

potential N95 user should receive a copy of Appendix D of the OSHA Respiratory 

Protection Standard (http://www.osha.gov/pls/oshaweb/owadisp.show_document?p_

table=standards&p_id=9784). Information about Appendix D and voluntary use 

of respirators can be found on the OSHA website at https://www.osha.gov/video/

respiratory_protection/voluntaryuse_transcript.html. 

Please be aware that N95s are not protective against alpha-diketones (diacetyl, 

2,3-pentanedione, or 2,3-hexanedione). In cases of dual exposure to dust and alphadiketones, 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. 

According to the NIOSH Criteria document [NIOSH 2016], employees should have baseline 

evaluations before they are allowed to work in or enter areas where they might be exposed 

to diacetyl, 2,3-pentanedione, or similar flavoring compounds. Air sampling results indicated 

that employees in the production area that roasted coffee, ground coffee, or weighed and 

packaged roasted coffee could be exposed to diacetyl above the NIOSH REL or STEL. 

1. Institute a medical monitoring program for employees who work or assist in the 

production area. 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 
Health Hazard Evaluation Report 2016-0005-3303 Page 25

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 a breakdown 

in exposure controls and potential risk for co-workers exists. 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. 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]. 
Page 26 Health Hazard Evaluation Report 2016-0005-3303

Appendix A: Tables

Table A1. Time-weighted average OSHA Method 1013/1016 personal and area full-shift 

air sampling results by location, NIOSH survey, February 2017

Analyte Sample Type Location N

Above 

LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Above 

REL

N

Diacetyl Personal Production Area 1 1 (100%) 5.6 5.6 1

Diacetyl Personal Roasting 2 2 (100%) 0.7 2.4 0

Diacetyl Area Café 5 5 (100%) 0.5 1.0 N/A

Diacetyl Area Outside 2 0 (0%) <0.3 <0.4 N/A

Diacetyl Area Production Area 12 10 (83%) <0.3 18.5 N/A

Diacetyl Area Production Office 2 2 (100%) 0.4 1.8 N/A

Diacetyl Area Roasting 4 4 (100%) 0.5 2.9 N/A

2,3-Pentanedione Personal Production Area 1 1 (100%) 3.3 3.3 0

2,3-Pentanedione Personal Roasting 2 2 (100%) 0.6 1.4 0

2,3-Pentanedione Area Café 5 5 (100%) 0.3 0.9 N/A

2,3-Pentanedione Area Outside 2 0 (0%) <0.3 <0.3 N/A

2,3-Pentanedione Area Production Area 12 10 (83%) <0.3 9.0 N/A

2,3-Pentanedione Area Production Office 2 2 (100%) 0.3 1.1 N/A

2,3-Pentanedione Area Roasting 4 3 (75%) <0.3 1.7 N/A

2,3-Hexanedione Personal Production Area 1 0 (0%) <0.2 <0.2 -

2,3-Hexanedione Personal Roasting 2 0 (0%) <0.2 <0.3 -

2,3-Hexanedione Area Café 5 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Outside 2 0 (0%) <0.2 <0.3 N/A

2,3-Hexanedione Area Production Area 12 0 (0%) <0.2 <0.3 N/A

2,3-Hexanedione Area Production Office 2 0 (0%) <0.2 <0.3 N/A

2,3-Hexanedione Area Roasting 4 0 (0%) <0.2 <0.3 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 limit of detection (LOD); < indicates below the LOD; % Above REL=percentage 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 used for direct comparisons with area 

samples; “Production Area” location includes employees that were cross-trained and performed tasks at 

different areas; “−“indicates that there is currently no REL for 2,3-hexanedione.
Health Hazard Evaluation Report 2016-0005-3303 Page 27

Table A2. Time-weighted average OSHA Method 1013/1016 personal partial-shift air sampling results by 

location, NIOSH survey, February 2017

Analyte Sample Type Location N Above LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Mean (range) Sample 

Duration (minutes)

Diacetyl Personal Grinding 1 1 (100%) 8.2 8.2 105 (105–105)

Diacetyl Personal Packaging 6 6 (100%) 2.2 6.1 113 (106–120)

Diacetyl Personal Production Area 1 1 (100%) 1.4 1.4 180 (180–180)

2,3-Pentanedione Personal Grinding 1 1 (100%) 5.2 5.2 105 (105–105)

2,3-Pentanedione Personal Packaging 6 6 (100%) 1.1 4.4 113 (106–120)

2,3-Pentanedione Personal Production Area 1 1 (100%) 0.9 0.9 180 (180–180)

2,3-Hexanedione Personal Grinding 1 0 (0%) <0.4 <0.4 105 (105–105)

2,3-Hexanedione Personal Packaging 6 0 (0%) <0.4 <0.4 113 (106–120)

2,3-Hexanedione Personal Production Area 1 0 (0%) <0.2 <0.2 180 (180–180)

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 limit of detection (LOD); < indicates below the 

LOD; ≤ indicates less than or equal to the LOD; % Above REL=percentage of samples above the NIOSH recommended exposure 

limit (REL); ppb=parts per billion; “Production Area” location includes cross-trained employees that performed tasks in different 

areas. 

Table A3. Summary of OSHA Method 1013/1016 personal air sampling results by task, NIOSH survey, 

February 2017

Analyte Task N

Above LOD

N (%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Mean (range) 

Sample Duration (minutes)

Diacetyl Grinding coffee beans 3 3 (100%) 14.8 31.8 15 (15–15)

Diacetyl Packaging coffee 5 5 (100%) 4.0 11.7 15 (15–15)

Diacetyl Roasting coffee beans 11 1 (9%) <0.6 1.5 16 (13–23)

2,3-Pentanedione Grinding coffee beans 3 3 (100%) 7.7 19.5 15 (15–15)

2,3-Pentanedione Packaging coffee 5 5 (100%) 2.9 6.2 15 (15–15)

2,3-Pentanedione Roasting coffee beans 11 1 (9%) <0.5 0.9 16 (13–23)

2,3-Hexanedione Grinding coffee beans 3 0 (0%) <0.7 <0.7 15 (15–15)

2,3-Hexanedione Packaging coffee 5 0 (0%) <0.7 <0.7 15 (15–15)

2,3-Hexanedione Roasting coffee beans 11 0 (0%) <0.5 <0.8 16 (13–23)

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 limit of detection (LOD); < indicates below the 

LOD; ≤ indicates less than or equal to the LOD; “All Over” includes cross-trained employees that performed tasks in different areas.
Page 28 Health Hazard Evaluation Report 2016-0005-3303

Table A4. Instantaneous evacuated canister method* air sampling results by task, NIOSH survey, 

February 2017

Task Description Diacetyl 

(ppb)

2,3-Pentanedione 

(ppb)

2,3-Hexanedione 

(ppb)

Grinding 5-pound bags of coffee 2.6 1.7 <1.2

Grinding 5-pound bags of coffee 7.6 4.1 <1.0

Grinding coffee 10.7 5.9 <1.3

Grinding coffee 8.1 4.4 <1.9

Grinding coffee 6.3 3.3 <1.3

Grinding coffee 6.9 3.8 <1.6

Grinding coffee 10.2 5.1 <1.7

Grinding coffee 11.9 6.1 <1.2

Cleaning chaff out of roaster exhaust lines 7.0 3.6 <2.0

Cleaning chaff out of roaster exhaust lines 12.1 6.4 <3.1

Cleaning chaff out of roaster exhaust lines 8.6 5.4 2.2

Dumping roasted beans from roaster into cooling bin 1.0 1.0 <1.2

Dumping roasted beans from roaster into cooling bin 0.6 <0.8 <1.4

Dumping roasted beans from roaster into cooling bin 1.1 1.0 <1.5

Dropping roasted beans from cooling bin into transfer container 0.9 <0.8 <1.4

Dropping roasted beans from cooling bin into transfer bin 0.5 <0.7 <1.2

Dropping roasted beans from cooling bin into transfer container 2.5 2.8 <1.4

Dropping roasted beans from cooling bin into transfer container 0.7 <0.7 <1.3

Dropping roasted beans from cooling bin into transfer container 0.8 <0.6 <1.1

Dropping roasted beans from cooling bin into transfer container 0.6 <0.6 <1.0

Dropping roasted beans from cooling bin into transfer container <0.5 <0.6 <1.1

Dumping roasted beans from transfer container into destoner 0.6 <0.7 <1.2

Dumping roasted beans from transfer container into destoner <0.6 <0.9 <1.6

Dumping roasted beans from transfer container into destoner 1.5 0.8 <1.1

Dumping roasted beans from transfer container into destoner 2.0 <1.5 <2.7

Quality control smelling tryer of beans 0.9 <1.1 <1.9

Scooping whole beans onto scale then into package 6.2 3.3 <1.0

Scooping whole beans onto scale then into package 7.2 4.1 <1.0

Scooping whole beans onto scale then into package 5.9 3.5 <1.0

Note: NIOSH=National Institute for Occupational Safety and Health; 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 2016-0005-3303 Page 29

Table A5. Summary of continuous area air monitoring results for mean concentrations of 

carbon dioxide, carbon monoxide, temperature, relative humidity, and total volatile organic 

compounds, NIOSH industrial hygiene survey, February 2017

Temperature Relative Total VOC Location CO2 (ppm)* CO (ppm)* (°F)* humidity (%)* (ppb)*

Roaster, day 1 553

(453–828)

2.3 

(0–7.7) − − 193(0–493)

Grinders, day 1 566

(456–1260)

3.4

(0–176.4) − − 497(0–11,604)

Packaging weigh 

station, day 1

616

(531–1059)

3.1

(0.7–16.0)

72.4

(62.7–81.1)

28.6

(17.8–40.3) −

Roaster, day 2 497

(433–840)

0.2

(0–12.1) − − ̶

Grinders, day 2 483

(430–679)

0.2

(0-4.3) − − 172(0–1052)

Packaging weigh 

station, day 2

587

(476–1073)

0.9

(0.5–6.8)

66.5

(62.0–71.6)

35.4

(27.1–41.6) −

Note: NIOSH=National Institute for Occupational Safety and Health; CO2

=carbon dioxide; CO=carbon 

monoxide; ppm=parts per million; °F=degrees Fahrenheit; VOC=volatile organic compounds; “-“indicates 

the measurement was not recorded. 

*Range can be seen in the parentheses.

Table A6. Summary of continuous personal air measurements for carbon monoxide, NIOSH 

industrial hygiene survey, February 2017

Job Title Work Area CO (ppm)*

Roaster, day 1 Roaster 2.2

(0–11)

Roaster, day 2 Roaster 0.2

(0–4)

Production Packaging 7.6

(3–13)

Production Grinding 20.9

(4–301)

Production Production and 

Administrative

3.8

(0–138)

Note: NIOSH=National Institute for Occupational Safety and Health; CO=carbon monoxide; ppm=parts per 

million.

*Mean concentrations of CO shown with range of measurements shown in the parentheses. 
Page 30 Health Hazard Evaluation Report 2016-0005-3303

Table A7. Prevalence of reported symptoms, NIOSH medical survey, March 2017

Experienced in the last 12 months Experienced in the last 4 weeks

Symptom N = 5 N = 5

Number (%) Number (%)

Nose symptoms* 5 (100%) 4 (80%)

Eye symptoms† 4 (80%) 3 (60%)

Sinusitis or sinus problems 5 (100%) 4 (80%)

Problem with ability to smell 0 (0%) –

Phlegm on most days for 3 months 0 (0%) –

Lower respiratory symptoms (reported at least 

one of the following) 3 (60%) 2 (40%)

 Chest wheezing or whistling 3 (60%) 2 (40%)

 SOB on level ground or walking up a slight a hill 1 (20%) –

 Breathing trouble 1 (20%) 1 (20%)

 Awoke with chest tightness 0 (0%) 0 (0%)

 Awoke with shortness of breath 0 (0%) 0 (0%)

 Usual cough‡ 0 (0%) 0 (0%)

 Asthma attack 0 (0%) 0 (0%)

Systemic symptoms(reported at least one of the 

following) 4 (80%) 3 (60%)

 Flu-like achiness or achy joints 3 (60%) 1 (20%)

 Fever or chills 3 (60%) 2 (40%)

 Unusual tiredness or fatigue 1 (20%) 1 (20%)

Note: N=number of participants; SOB=shortness of breath; “-“=no four week question was 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.

‡This question did not specifically ask about a cough within the past 12 months; participants were asked, “Do you usually 

have a cough?” If the participants answered yes to that question, they were then asked, “Have you had a cough at any 

time in the last 4 weeks?”
Health Hazard Evaluation Report 2016-0005-3303 Page 31

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Keywords: NAICS 311920 (Coffee roasting), Oregon, diacetyl, 2,3-pentanedione, 

2,3-hexanedione, coffee, volatile organic compounds (VOCs). 
Health Hazard Evaluation Report 2016-0005-3303 Page 41

The Health Hazard Evaluation Program investigates possible health hazards in the workplace 

under the authority of the Occupational Safety and Health Act of 1970 (29 U.S.C. § 669(a)

(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 

National Institute for Occupational Safety and Health (NIOSH).

Citations to Web sites external to NIOSH do not constitute NIOSH endorsement of the 

sponsoring organizations or their programs or products. NIOSH is not responsible for the 

content of these Web sites. All Web addresses referenced in this document were accessible as 

of the publication date.

Acknowledgments

Desktop Publisher: Tia McClelland 

Data Analysis Support: Nicole Edwards, Kathy Fedan, and Brian Tift

NIOSH Laboratory Assistance: Dru Burns, Ryan LeBouf, and Anand Ranpara

Site Visit Team Members: Michael Beaty, Brie Hawley, Stephen Martin, Jr., Randall Nett, and 

Laura Reynolds

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Administration Regional Office have also received a copy. This report is not copyrighted and 

may be freely reproduced.

This report is available at http://www.cdc.gov/niosh/hhe/reports/pdfs/2016-0005-3303.pdf.

All other HHE Reports may be found at http://www2a.cdc.gov/hhe/search.asp. 

Recommended citation for this report:

NIOSH [2017]. Health hazard evaluation report: evaluation of exposures and 

respiratory health at a coffee roasting and packaging facility. By Hawley B, 

Reynolds L, Nett R, Martin S. 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. 2016-0005-3303.
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