Health Hazard Evaluation Report 2016-0109-3343 Page 1

Evaluation of exposures and respiratory 

health at a coffee roasting and packaging 

facility and two off-site retail cafés

Report No. 2016-0109-3343

March 2019

Tia McClelland, MPH

Randy J. Boylstein, MS, REHS

Stephen B. Martin, Jr., PhD, PE

Michael Beaty

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 2016-0109-3343

Contents

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

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

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

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

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

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

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

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

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

Conclusions........................................ 23

Recommendations............................. 24

Appendix A: Tables............................ 29

References.......................................... 36

Acknowledgements........................... 46

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 2016-0109-3343 Page i

We evaluated respiratory health and 

airborne exposures to alpha-diketones 

(diacetyl, 2,3-pentanedione, and 

2,3-hexanedione), other volatile organic 

compounds, carbon monoxide, and 

carbon dioxide among employees at a 

coffee roasting and packaging facility 

and two retail cafés. Diacetyl and 

2,3-pentanedione were detected in a 

majority of full-shift personal breathing 

zone air samples, with a maximum 

concentration of diacetyl of 13.9 parts 

per billion and of 2,3-pentanedione of 

15.6 parts per billion. Five of the fullshift samples, captured from baristas, 

exceeded the NIOSH recommended 

exposure limit for diacetyl of 5 parts 

per billion. In addition, two 15-minute 

short-term exposure samples collected 

on an employee grinding roasted coffee 

beans exceeded the NIOSH shortterm exposure limit for diacetyl. Two 

15-minute samples collected on an 

employee grinding roasted coffee beans 

was above the short-term exposure 

limit for 2,3-pentanedione. Air levels 

of carbon monoxide at each location 

were below the exposure limits. Nose, 

eye, and sinus symptoms were the 

most commonly reported symptoms. 

Wheezing was the most common 

lower respiratory symptom reported. 

All spirometry tests were interpreted 

as normal. One participant had high 

exhaled nitric oxide, a marker of allergic 

airways inflammation. We recommend 

introducing prescribed amounts of 

fresh, outdoor air into the café spaces, 

operating the ventilation system in the 

roastery production space continuously 

during the work shift; relocating 

the grinders in the basement of the 

downtown café; installing local exhaust 

ventilation; implementing administrative 

controls such as modification of work 

practices; and training employees about 

work-place hazards. We also recommend 

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 the owner of a coffee roasting and packaging facility and offsite retail cafés regarding concerns about exposures to and health effects from diacetyl and 

2,3-pentanedione during coffee roasting, coffee grinding, and café tasks. 

What We Did

● We visited the roastery production space and 

two off-site retail cafés on May 15-18, 2017. 

● We collected full-shift (hours), task (minutes), 

and instantaneous (seconds) air samples 

to measure concentrations of the alphadiketones diacetyl, 2,3-pentanedione, and 

2,3-hexanedione over multiple days during the 

visit.

● We measured real-time air levels of carbon 

monoxide and carbon dioxide.

● We assessed the ventilation system at each 

location.

● We administered a health questionnaire to 

employees and performed breathing tests; we 

mailed employees their individual breathing 

test results.

What We Found

● On full-shift sampling, some employees 

(baristas) were exposed to diacetyl and 

2,3-pentanedione at concentrations above the 

recommended exposure limits of 5 parts per 

billion and 9.3 parts per billion respectively. 

The highest measured concentrations of 13.9 

parts per billion for diacetyl and 15.6 parts per 

billion for 2,3-pentanedione were measured on 

a café employee while grinding roasted coffee 

beans in the basement of the downtown café. 

● Levels of diacetyl in the air during short-term 

sampling were higher for tasks involving 

grinding roasted beans (maximum 124.5 parts 

per billion).
Page ii Health Hazard Evaluation Report 2016-0109-3343

● Carbon monoxide levels were low at all locations.

● The ventilation at the roastery was effective at controlling airborne concentrations 

of alpha-diketones below the recommended exposure limits for diacetyl and 

2,3-pentanedione; ventilation at the cafés was ineffective at controlling exposures to 

acceptable levels. 

● Nose, eye, and sinus symptoms were the most commonly reported symptoms. One 

employee reported symptoms that were caused or aggravated by dust.

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

symptom.

● All spirometry tests were interpreted as normal. 

● One of nine 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.

● Install local exhaust ventilation at grinder locations to capture diacetyl, 

2,3-pentanedione, and carbon monoxide emissions from ground coffee.

● Relocate the cold brew grinder in the basement of the downtown café closer to an 

outside wall and install either an exhaust fan or ducted local exhaust ventilation system 

to exhaust contaminants generated during grinding directly outdoors.

● Operate the ventilation system in the roastery production space continuously during the 

work shift.

● Work with a ventilation expert to bring in appropriate levels of outdoor air to meet 

ASHARAE ventilation guidelines for cafés.

● Provide an alternative method to hand-blending roasted coffee beans that minimizes 

employee contact with roasted beans during blending.

● Eliminate the use of dry sweeping as much as possible during cleaning; particularly 

in areas where green beans are stored. Instead, use a vacuum system with a highefficiency particle air filter and wet methods whenever possible. 

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

reducing exposures to below the recommended exposure limits. If air levels in the cafés 

are not below recommended levels, work with a ventilation engineer to install local 

exhaust associated with café grinder tasks.

● Make N95 disposable filtering-facepiece respirators available for voluntary use for 

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

beans, cleaning the roaster, or cleaning the green bean storage area. 
Health Hazard Evaluation Report 2016-0109-3343 Page iii

● Encourage employees to report new or ongoing respiratory symptoms to their personal 

healthcare providers and to a designated individual at the workplace. 

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

What Employees Can Do

● Operate the ventilation system at all times in the roastery production space during the 

work shift. 

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

● Follow your employer’s instructions for an alternative method to hand-blending roasted 

coffee beans. 

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

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

storage area.

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

providers and a designated individual at your workplace. 

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

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

employer.
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Health Hazard Evaluation Report 2016-0109-3343 Page v

Abbreviations

ACGIH® American Conference of Governmental Industrial Hygienists

APF Assigned protection factor

cfm Cubic feet per minute

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 1-second forced expiratory volume

Fres Resonant frequency

FVC Forced vital capacity

HVAC Heating, ventilation, and air-conditioning

IDLH Immediately dangerous to life or health

LOD Limit of detection

μg Microgram 

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

RH Relative humidity

SMR Standardized morbidity ratio

STEL Short-term exposure limit

TLV® Threshold limit value

TVOC Total volatile organic compound

TWA Time-weighted average

VOC Volatile organic compound

X5 Reactance at 5 Hertz
Health Hazard Evaluation Report 2016-0109-3343 Page 1

Summary 

In March 2016, the National Institute for Occupational Safety and Health’s Health Hazard 

Evaluation Program received a request from the owner of a coffee roasting and packaging 

facility and off-site retail cafés with 15 employees regarding concerns about exposures to 

and health effects from diacetyl and 2,3-pentanedione during coffee roasting, coffee grinding, 

and café tasks. In May 2017, we conducted the medical survey, industrial hygiene survey, 

and ventilation assessment at the roastery production space and two off-site retail cafés. 

The industrial hygiene survey consisted of collecting personal breathing zone and area air 

samples for alpha-diketones (i.e., diacetyl, 2,3-pentanedione, and 2,3-hexanedione). We used 

continuous monitoring instruments to measure total volatile organic compounds, carbon 

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

tasks. We also conducted a ventilation assessment in both cafés and the roastery production 

space location. The medical survey consisted of a health questionnaire and breathing tests. 

An interim letter reporting industrial hygiene results and recommendations was sent to the 

company following our visit. 

Most time-weighted average air concentrations of diacetyl and 2,3-pentanedione were below 

the NIOSH recommended exposure limits. Five of the 13 full-shift samples collected during 

the survey exceeded the NIOSH recommended exposure limit for diacetyl of 5 parts per 

billion, with a maximum concentration of 13.9 parts per billion. We identified jobs where 

some work tasks resulted in relatively higher air concentrations of diacetyl than other tasks. 

Specifically, grinding roasted coffee beans was associated with higher diacetyl levels. 

Overall, the most commonly reported symptoms were associated with mucous membranes, 

specifically the nose, eyes, and sinuses. Most employees reported that they did not feel that 

their symptoms were caused or aggravated by work-related exposures. Wheezing or whistling 

in the chest was the most commonly reported lower respiratory symptom, 33% of employees 

reported experiencing this symptom in the last 12 months. All administered spirometry 

tests (n=9) were normal. One of nine participants had high exhaled nitric oxide, a marker of 

allergic airways inflammation, and three of nine participants had airway obstructions. We 

recommend moving the cold brew grinders in the basement of the downtown café closer 

to an outside wall and installing an exhaust fan or ducted local exhaust ventilation system 

to exhaust contaminants generated during grinding directly outdoors. We also recommend 

introducing prescribed amounts of fresh, outdoor air to the café spaces to help further reduce 

airborne concentrations. Further, we recommended operating the ventilation system in the 

roastery production space continuously during roastery operating hours, training employees 

about workplace hazards, and establishing a medical monitoring program to identify any 

employees who may 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 2016-0109-3343

Introduction

In March 2016, the National Institute for Occupational Safety and Health (NIOSH) received 

a management request for a health hazard evaluation at a coffee roasting and packaging 

facility and two off-site retail café locations regarding potential employee exposure to diacetyl 

and 2,3-pentanedione during coffee processing and café tasks. In May 2017, we conducted 

medical and industrial hygiene surveys and a ventilation assessment in all three locations; 

the roastery production space, the downtown café, and the uptown café. We collected area 

and personal breathing zone air samples for volatile organic compounds (VOCs), including 

diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We monitored carbon monoxide (CO), 

carbon dioxide (CO2), and total VOCs. After the visit, we provided two interim reports with 

recommendations. 

Background 

Diacetyl and 2,3-Pentanedione 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

should be taken to reduce exposures in the workplace.

These exposure limits and the accompanying recommendations for control of exposures 

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

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

in 1,000 workers exposed to diacetyl levels of 5 parts per billion (ppb) as a time-weighted 

average (TWA) for 8 hours a day, 40 hours a week for a 45-year working lifetime would 
Health Hazard Evaluation Report 2016-0109-3343 Page 3

develop reduced lung function (defined as forced expiratory volume in one second [FEV1] 

below the lower limit of normal) as a result of that exposure. NIOSH predicted that around 1 

in 10,000 workers exposed to diacetyl at 5 ppb for a 45-year working lifetime would develop 

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

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

time would be at lower risk for adverse lung effects.

2,3-Hexanedione

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

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

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

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

occupational exposure limits for 2,3-hexanedione.

Carbon Monoxide and Carbon Dioxide

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

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

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

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

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) (Mandatory)

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

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

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

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

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

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

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

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

can be considered using available occupational exposure references and recommendations 

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

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

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

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

peer-reviewed scientific literature and publishes recommendations for levels of substances 
Page 4 Health Hazard Evaluation Report 2016-0109-3343

in air based on an 8-hour workday and 40-hour workweek. These recommendations are 

called threshold limit values (TLVs®) [ACGIH 2018a]. ACGIH TLVs are not standards; they 

are health-based guidelines derived from scientific and toxicological information. ACGIH 

provides TLV-TWA guidelines that are levels that should not be exceeded during any 8-hour 

workday of a 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 

2018a]. Additionally, ACGIH provides TLV-Ceiling values which are levels that should 

not be exceeded at any time during a work shift. The ACGIH TLV-TWA for diacetyl is 10 

ppb. The TLV-STEL for diacetyl is 20 ppb. Currently, there is no TLV-TWA or TLV-STEL 

for 2,3-pentanedione. ACGIH has placed 2,3-pentanedione on the 2017 list of Chemical 

Substances and Other Issues Under Study [ACGIH 2018b]. 

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

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

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

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

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

[NIOSH 2010]. Some chemicals have ceiling values which are concentrations that should not 

be exceeded at any time [NIOSH 2010]. 

For some chemicals, NIOSH has established an Immediately Dangerous to Life or Health 

(IDLH) value. An IDLH value is a concentration of an air contaminant that can cause death 

or immediate or delayed permanent adverse health effects, or prevent escape from such an 

environment. Currently, NIOSH has RELs and STELs for diacetyl and 2,3-pentanedione. 

NIOSH does not have a REL or a STEL for 2,3-hexanedione. NIOSH does not have ceiling 

limits or IDLH values for diacetyl, 2,3-pentanedione, or 2,3-hexanedione. 

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

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

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

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

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

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

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

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

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

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

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

lungs) can result in additive effects [ACGIH 2018a]. 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 
Health Hazard Evaluation Report 2016-0109-3343 Page 5

below the NIOSH REL for diacetyl [NIOSH 2016].

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

2017.

OSHA* ACGIH NIOSH

Compound PEL TLV STEL REL STEL IDLH

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

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

2,3-Hexanedione - - - - - -

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

Carbon 

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

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

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

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

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

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

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

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

during a 40-hour workweek.

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

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

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

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

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

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

exceeded at any time.

Obliterative Bronchiolitis

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

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

breath on exertion, or wheeze, that do not typically improve away from work [NIOSH 2012]. 

Occupational obliterative bronchiolitis has been identified in flavoring manufacturing workers 

and microwave popcorn workers who worked with flavoring chemicals or butter flavorings 

[Kreiss 2013; Kim et al. 2010; Kanwal et al. 2006]. Obliterative bronchiolitis has also been 

identified among employees at a coffee roasting and packaging facility that produced unflavored 

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

diacetyl and 2,3-pentanedione concentrations in the air that were elevated (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, employees 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 employees who were 

diagnosed with obliterative bronchiolitis had worked in the flavoring area. To date, no cases of 

obliterative bronchiolitis have been reported among employees at coffee roasting and packaging 
Page 6 Health Hazard Evaluation Report 2016-0109-3343

facilities that produce only unflavored coffee.

Work-related Asthma

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

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

[Tarlo 2016; Tarlo and Lemiere 2014; OSHA 2014; Henneberger et al. 2011; NIOSH 2017]. 

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

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

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

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

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

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

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

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

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

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

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

coffee dust [Oldenburg et al. 2009].

Process Description

At the time of the NIOSH survey, the company consisted of four locations: a roastery 

production space, a kiosk, the downtown café, and the uptown café. The company employed 

15 employees; 10 of these employees performed tasks only in the company’s cafés and kiosk 

location; four employees perform tasks in all of the company’s locations, and one employee 

only performed tasks in the roastery production space. The NIOSH evaluated the roastery, the 

downtown café, and the uptown café. 

The roastery production space was approximately 1,081 square feet dedicated to green bean 

storage, roasting, and packaging. The roastery production space contained painted brick 

walls and a cement floor. A garage door was located at the front of the building, and during 

the spring and fall months, the man door located in the front of the building was propped 

open. The roastery production space housed the facility’s San Franciscan roaster. Roasting 

was done about four hours at a time twice weekly. Approximately 300 pounds of coffee was 

roasted per batch. After the coffee was roasted, roughly 90% of the coffee was immediately 

packaged. Half of the roasted coffee was hand packed into one and five pound heat-sealed, 

foil-lined bags. The remainder of the roasted coffee was placed into plastic buckets and 

distributed to the cafés and the kiosk location. During the NIOSH survey, approximately two 

to three employees conducted roasting and packaging tasks. 

The downtown café was approximately 725 square feet and contained a seating area and 

a bar where various coffee drinks were made, and pastries were served. The downtown 

café had a professional grade espresso machine, dual station coffee brewer, one pound 

professional grade coffee grinder, and two professional grade espresso grinders. Small 
Health Hazard Evaluation Report 2016-0109-3343 Page 7

amounts of roasted coffee beans were ground in the café as drinks were ordered. Twice a 

week, employees transported roasted coffee beans to the downtown café, and employees 

ground the coffee in the basement of the café using two professional grade grinders; this 

ground coffee was used to make the company’s cold brew coffee. Grinding usually occurred 

in 30-minute intervals. An employee placed roughly three pounds of roasted coffee beans in 

each grinder at a time. To prepare the cold brew, an employee placed the ground coffee in a 

metal extraction container and added water; this mixture sat overnight. The following day, an 

employee collected the cold brew liquid extract in bottles and supplied it to the cafés. 

The uptown café was approximately 950 square feet and contained a basement used for 

storage, a seating area, and a bar where various coffee drinks were made and pastries were 

served. The uptown café had a professional grade espresso machine, a single station coffee 

brewer, a one pound professional grade coffee grinder, and three professional grade espresso 

grinders. Small amounts of roasted coffee beans were ground in the café as drinks were 

ordered. A tap system was used at the uptown café to serve cold brew coffee. 

Quality Control 

In the roastery production space, coffee was periodically brewed and taste tested for quality 

control measures. The brewing location was located on a workbench in the corner of the 

roastery.

Cleaning Activities

Inside the roastery production space, employees used brooms to sweep the floor and wet 

or dry wipes on work and equipment surfaces. At the downtown café and the uptown café, 

employees used brooms to sweep the floor and wet or dry wipes on tabletops, counters, and 

equipment surfaces. 

Personal Protective Equipment 

Employees were not required to wear a company uniform, protective clothing, or respiratory 

protection. We did not observe any employees wearing respiratory protection during roasting 

or grinding activities. 

Methods

We visited the roastery production space and two off-site retail cafés in May 2017. We held 

an opening meeting with the owner of the company, toured the three locations, collected air 

samples, performed a ventilation assessment, had informal interviews with employees, and 

conducted medical testing. At the conclusion of our site visit, we held a short closing meeting 

with the owner of the company. Two interim reports were sent to the company following our 

visit. 

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 processing and café tasks;
Page 8 Health Hazard Evaluation Report 2016-0109-3343

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

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

3. Measure levels of CO, and CO2 in all three locations;

4. Assess ventilation systems and their effect on exposure levels in all three locations;

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

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

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

7. Compare employees’ prevalence of lower respiratory symptoms and healthcare 

provider-diagnosed asthma to expected levels based on general population values.

Industrial Hygiene Survey

Sampling Times for Alpha-Diketones 

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

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

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

at the cafés. For diacetyl, 2,3-pentanedione, and 2,3-hexanedione, the air samples were 

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

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

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

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

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

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

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

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

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

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

individual air sampling results.

Air Sampling and Analysis Using Modified Occupational Safety and Health Administration 

(OSHA) Methods 1013/1016

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

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

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

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

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

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

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

a flow rate of 50 milliliters per minute (mL/min). The sampling setup was attached to an 

employee’s breathing zone or placed in an area basket in various places throughout each 

location. For full-shift sampling, we collected two consecutive 3-hour samples and calculated 

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

results reflected a full work shift (8-hour) TWA exposure. Although this may introduce some 
Health Hazard Evaluation Report 2016-0109-3343 Page 9

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

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

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

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

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

duration of the task being performed. 

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

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

containing 3-pentanone as an internal standard. Samples were analyzed using an Agilent 

7890/7001 gas chromatograph/mass spectrometer system operated in selected ion monitoring 

mode for increased sensitivity compared to the traditional flame ionization detector used in 

OSHA Methods 1013 and 1016 [LeBouf and Simmons 2017].

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

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

The LODs for the visit were 0.01 micrograms per sample (μg/sample) for diacetyl, 0.012 μg/

sample for 2,3-pentanedione, and 0.020 μg/sample for 2,3-hexanedione; these were based 

on the lowest mass used in the calibration curve. For a typical full-shift TWA air sample, 

these equate to 0.32 ppb for diacetyl, 0.33 ppb for 2,3-pentanedione, and 0.48 ppb for 

2,3-hexanedione. The LODs for task samples 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. 

Air Sampling and Analysis Using Evacuated Canisters

We collected personal and area full-shift air samples and instantaneous task-based and source 

air samples for VOCs including diacetyl, 2,3-pentanedione, and 2,3-hexanedione using 

evacuated canisters. The evacuated canister sampling setup consisted of a 450-mL evacuated 

canister equipped with an instantaneous flow controller that was designed for a short 

sampling duration (less than 30 seconds). Instantaneous samples were taken by opening the 

evacuated canister to grab a sample of air to help identify point sources of alpha-diketones. 

For task-based air samples, a NIOSH employee placed the inlet of the flow controller by the 

employee’s personal breathing zone as they performed their work task to replicate exposure. 

For source air samples, a NIOSH employee placed the inlet of the flow controller directly at 

the source of interest. 

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

spectrometer system [NIOSH 2018b], with the addition of acetaldehyde, acetonitrile, and 

styrene to the list of quantified compounds. For the visit, the LODs were 0.39 ppb for 

diacetyl, 0.54 ppb for 2,3-pentanedione, and 0.96 ppb for 2,3-hexanedione based on a threetimes dilution factor, which is typical for restricted flow controller samplers. 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. 
Page 10 Health Hazard Evaluation Report 2016-0109-3343

Real-time Air Sampling

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

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

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

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

where coffee could be releasing TVOCs. Areas where higher concentrations of TVOCs are 

measured may benefit from further sampling to characterize specific exposures to alphadiketones. We found increased concentrations around areas where grinding occurred and near 

pour over areas. We also collected real-time measurements of CO2, CO, temperature, and 

relative humidity (RH) using TSI Incorporated (Shoreview, MN) VelociCalc Model 9555-X 

Multi-Function Ventilation Meters equipped with Model 982 IAQ probes.

Ventilation Assessment

Physical measurements of each facility were taken with a Model DISTO E7100i lasertape measure (Leica Geosystems AG, Heerbrugg, Switzerland) or a standard tape measure. 

Ventilation measurements were taken with a Model EBT731 Balometer Air Balancing 

Instrument (Alnor Products, TSI Incorporated, Shoreview, MN). Information on existing 

ventilation equipment, including make, model, and specified performance levels, was also 

collected when possible.

NIOSH Medical Survey

Participants 

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

May 17, 2017. Participation was voluntary; written informed consent was obtained from 

each participant before testing. The survey included, in the order performed, a medical and 

work history questionnaire, quantification of exhaled nitric oxide, impulse oscillometry, 

and spirometry. We mailed participants their individual reports explaining their breathing 

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

physician. 

Questionnaire 

We used an interviewer-administered computerized questionnaire to ascertain symptoms 

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

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

derived from five standardized questionnaires, the European Community Respiratory Health 

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

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

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

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

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

the standardized questionnaires. We also supplemented our questionnaire with additional 

respiratory and systemic symptom questions. 

Spirometry

The purpose of the spirometry test was to determine a person’s ability to move air out of 
Health Hazard Evaluation Report 2016-0109-3343 Page 11

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

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

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

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

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

et al. 2005]. 

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

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

from NHANES III data to define abnormal spirometry [Hankinson et al. 1999]. We defined 

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 at all frequencies between 5 Hertz and the Fres. The predicted 

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

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

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

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

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

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

2015]. We interpreted the test as normal if both the R5 and X5 were normal [Smith 2015]. 
Page 12 Health Hazard Evaluation Report 2016-0109-3343

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

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

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

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

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

Fractional Exhaled Nitric Oxide (FeNO) 

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

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

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

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

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

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

Statistical Analysis 

Industrial Hygiene Survey and Ventilation Assessment

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

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

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

denoted by a “<” symbol.

Medical Survey

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

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

prevalence of symptoms and diagnoses among participants to expected prevalence of a 

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

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

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

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

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

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

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

Results

Industrial Hygiene Survey Results

Personal and Area Full-shift Air Sampling Results

OSHA Methods 1013/1016

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

two off-site retail café locations and the roastery where roasting and packaging occurred. 

We collected 13 personal and 37 area full-shift air samples. Five personal air samples (four 

from the uptown café and one from the downtown café) were above the NIOSH REL for 
Health Hazard Evaluation Report 2016-0109-3343 Page 13

diacetyl of 5 ppb, and one sample from the downtown café was above the NIOSH REL for 

2,3-pentanedione of 9.3 ppb. All of these samples were collected on baristas. A downtown 

café employee who ground roasted coffee beans (for cold brew coffee) for approximately 

30 minutes during the six hour sampling had the highest exposure to diacetyl (13.9 ppb) and 

2,3-pentanedione (15.6 ppb).

Except for this employee’s exposure, the employees at the downtown café generally had 

lower exposures to diacetyl and 2,3-pentanedione than those at the uptown café. The highest 

exposure to diacetyl at the uptown café was 5.8 ppb. All personal samples were below the 

LOD for 2,3-hexanedione. 

Six of twenty-one area full-shift air samples in the cafés (three at the uptown café and three 

at the downtown café) were above the NIOSH REL for diacetyl. 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. 

The following areas at the uptown café had full-shift levels that exceeded the NIOSH REL 

for diacetyl: the counter near the grinders (7.6 ppb), the front corner window seating area (7.5 

ppb), and the counter near the pour over area (6.4 ppb). The following areas at the downtown 

café had full-shift air levels that exceeded the NIOSH REL for diacetyl: the bar between the 

espresso grinders and the espresso machine (5.5 ppb), the bar near the pour over areas (5.4 

ppb), and the bar between the grinders and brewers (5.4 ppb). Overall, the highest full-shift 

average area samples for diacetyl were measured near café grinders and pour over areas. 

All area samples were below the NIOSH REL for 2,3-pentanedione and 2,3-hexanedione; 

however, one sample collected at the front corner seating area at the uptown café had 

a full-shift air level of 9.0 ppb for 2,3-pentanedione. All area samples collected at the 

roastery production space were below the NIOSH REL for diacetyl, 2,3-pentanedione, and 

2,3-hexanedione.

Task-based Air Sampling Results

Table A2 presents the results of diacetyl, 2,3-pentanedione, and 2,3-hexanedione air 

concentrations by location for personal 15-minute task-based samples. We collected 17 

personal task-based air samples using OSHA Methods 1013/1016. Two 15-minute samples 

of an employee grinding roasted coffee beans at the downtown café exceeded the NIOSH 

STELs for both diacetyl of 25 ppb and 2,3-pentanedione of 31 ppb, with the highest exposure 

to diacetyl of 124.5 ppb and 2,3-pentanedione of 133.8 ppb. All other task-based samples 

were below NIOSH STELs. Two 15-minute samples of an employee grinding roasted coffee 

beans at the downtown café exceeded the LOD for 2,3-hexanedione; all other samples were 

below the LOD for 2,3-hexanedione.

Instantaneous Source Air Sampling Results

Table A3 presents the results from the six source air samples that were collected inside the 

downtown café during the visit in May 2017. All evacuated canisters were equipped with 

an instantaneous flow controller with a sample duration of approximately 30 seconds. We 

sampled in the basement of the downtown café and captured a sample at the grinder outlet 
Page 14 Health Hazard Evaluation Report 2016-0109-3343

while grinding was occurring. Air concentrations were 678 ppb and 1496 ppb for diacetyl, 

729 ppb and 1429 ppb for 2,3-pentanedione, and 22.8 ppb and 51.2 ppb for 2,3-hexanedione. 

We captured two additional samples over the top of the cold brew metal soaking vat. 

Air concentrations were 33.1 ppb and 17.7 ppb for diacetyl, 42.3 ppb and 21.1 ppb for 

2,3-pentanedione, and 3.9 ppb and <0.9 ppb for 2,3-hexanedione. We also collected two 

samples inside the café at the espresso grinder and espresso machine while espresso was 

being made. Air concentrations were 4.9 ppb and 23.1 ppb for diacetyl, 5.3 ppb and 26.4 ppb 

for 2,3-pentanedione, and <1.0 ppb and 1.1 ppb for 2,3-hexanedione. In the basement of the 

downtown café, diacetyl concentrations ranged from 17.7 ppb – 1496 ppb; 2,3-pentanedione 

concentrations ranged from 21.1 ppb – 1429 ppb; and 2,3-hexanedione concentrations ranged 

from <0.9 ppb – 51.2 ppb. 

Instantaneous Task-Based Air Sampling Results

Table A4 presents the results from the ten task-based air samples collected at the roastery 

production space during the visit in May 2017. All evacuated canisters were equipped with 

an instantaneous flow controller with a sample duration of approximately 30 seconds. Results 

should not be compared to the 15-minute STELs. We sampled one employee while dumping 

roasted coffee beans into a cooling pan during two different roasts. Air concentrations ranged 

from 0.6 ppb – 3.1 ppb for diacetyl, <0.5ppb – 2.5ppb for 2,3-pentandedione and <0.9 ppb – 

2.2 ppb for 2,3-hexanedione. Another sample was captured while roasted coffee beans were 

being dumped into the cooling pan. Air concentrations were <0.4 ppb for diacetyl, 0.6 for 

2,3-pentanedione, and <1.0 for 2,3-hexanedione. Two samples were captured during the hand 

blending of two types of roasted coffee in five-gallon buckets. Air concentrations were 15.5 

ppb and 5.2 ppb for diacetyl, 11.4 ppb and 3.2 ppb for 2,3-pentanedione, and <1.0 ppb and 

<0.9 ppb for 2,3-hexanedione during hand blending. Two additional samples were captured 

while packaging and weighing coffee into 5 pound bags. Air concentrations were 2.9 ppb and 

1.9 ppb for diacetyl, 2.2 ppb and 1.4 ppb for 2,3-pentanedione, and <0.9 ppb for both samples 

for 2,3-hexanedione while packaging and weighing coffee into 5 pound bags. One sample 

was captured while coffee was being packed and weighed into bags. Air concentrations were 

2.4 ppb for diacetyl, 1.6 ppb for 2,3-pentanedione, and <1.0 ppb for 2,3-hexanedione. 

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

Organic Compounds (TVOCs)

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

collected during the visit. In all locations, indoor CO levels were well below the NIOSH 

ceiling of 200 parts per million (ppm). The highest reading of 23.7 ppm was collected at 

the downtown café on the bar between the espresso grinders and espresso machine. Over 

the multi-day sampling period, the average CO2 levels were 1,468 ppm at the uptown café, 

1,214 ppm at the downtown café, and 583 ppm at the roastery production space. The average 

outdoor CO2 level was 447 ppm. During the visit, total VOCs were recorded at the cafés. At 

the downtown café the following peak total VOC concentrations were observed; 2,523 ppb 

on the bar between the espresso grinder and machine (May 16, 2017 at 2:25pm), 3,486 ppb 

on the bar between the grinders and brewers (May 17, 2017 at 8:37am), and 544 ppb in the 

basement next to the grinders (May 18, 2017 at 8:44am). At the uptown café the following 

peak total VOC concentrations were observed; 1,661 ppb on the counters near the grinders 
Health Hazard Evaluation Report 2016-0109-3343 Page 15

(May 16, 2017 at 11:15am), 1,285 ppb on the counter near the grinders (May 17, 2017 at 

11:27am), and 1,357 ppb on the counters near the grinders (May 18, 2017 at 12:09pm) and 

1,378 ppb on the counter near the pour over area (May 18, 2017 at 9:26am). At the roastery 

production space total VOCs were only collected on May 18, 2017 in two locations; on the 

table near the roaster and on the weighing table. A peak total VOC concentrations of 77 ppb 

was observed on the table near the roaster (1:07pm) and a peak of 533 ppb was observed on 

the weighing table (11:48am). 

Ventilation Assessment

Roastery

Ventilation, heating, and cooling at the roastery was provided by a single Nordyne (Nortek 

Global HVAC, LLC, O’ Fallon, MO) Model B6BMM030K-B air handling unit (AHU). The 

unit was mounted on the northeastern wall and fed a single galvanized sheet metal supply 

duct running from the unit to the southwest along the ceiling of the space. The supply 

duct fed eight 4-inch by 10-inch supply vents over its length, although one vent at the far 

end of the duct was completely covered with tape. Return air was pulled back to the unit 

through a single 15-inch by 20-inch opening at the bottom of the unit. The return opening 

was covered with a single 14-inch × 20-inch × 1-inch pleated air filter (brand and efficiency 

level unknown). The air filter in place was discolored from a substantial amount of collected 

particulate matter. The filter was also smaller than the return opening to the AHU, so a 

considerable amount of return air was bypassing the filter. The roastery AHU was controlled 

by a wall-mounted thermostat and was operated as desired by employees in the area. The 

unit was generally off, but when powered on, it circulated 1145 cubic feet per minute (cfm) 

of air throughout the space. However, the air being moved was 100% recirculated air from 

the roasting space with no fresh, outdoor air (as is common in homes). The San Franciscan 

roaster located in the space was ducted to the outdoors. There were no visible signs of smoke 

while the roaster was operating. 

Uptown Café

The uptown café was heated, cooled, and ventilated with one Armstrong Air (West Columbia, 

SC) Model BSC2M24C00NA1P-1 AHU installed in a largely unfinished portion of the 

basement. Supply air from the unit flows through a fiberglass-wrapped galvanized sheet 

metal main supply duct and some fiberglass flexible ductwork to ten 11-inch × 5-inch supply 

vents installed in the floor around the perimeter of the first-floor café space. Return air was 

pulled back to the AHU through two 26-inch × 12-inch grilles installed in the vertical wall 

separating the café serving area from the bathroom. Fiberglass-wrapped galvanized sheet 

metal ducts carried the return air back to the unit in the basement. The AHU in the uptown 

café was controlled by a wall-mounted thermostat behind the serving bar and it cycled on and 

off depending on the temperature set-point. When powered on, the AHU recirculated 610 cfm 

throughout the café space without supplying any fresh, outdoor air.

Downtown Café

The downtown café was heated, cooled, and ventilated by a combination system installed 

horizontally in the basement of the building. Heating and air movement was provided by an 

Allied Air (West Columbia, SC) Model 95G1UHD Furnace. Air conditioning was provided 
Page 16 Health Hazard Evaluation Report 2016-0109-3343

by an attached Rheem (Fort Smith, AR) Model RCFL-HM3617CC indoor coil unit. Supply 

air through the combination system traveled through an insulated galvanized sheet metal 

main duct and fiberglass flexible ductwork branches to eight 16-inch × 5-inch supply vents 

installed in the floor around the perimeter of the first-floor café space. Return air was pulled 

back to the AHU through a single 14-inch × 12-inch grille in the floor behind the café serving 

bar. Fiberglass-wrapped galvanized sheet metal ducts carried the return air back to the unit 

in the basement. The downtown café AHU was controlled by a wall-mounted thermostat that 

cycled the unit on and off depending on the temperature set-point. When powered on, the 

AHU recirculated 1070 cfm throughout the café space without supplying any fresh, outdoor 

air. No mechanical ventilation supply vents or return grilles served the basement of the 

building. 

 

Medical Survey Results 

Demographics

Nine of 15 employees (60%) participated in the medical survey. The majority of participants 

were male (67%) and Caucasian (89%), with a mean age of 27 years and average tenure at 

the company of two years. Three (33%) participants worked at another coffee roasting and 

packaging facility or café prior to working at this facility. Three (33%) participants were 

current or former smokers. 

Five of the nine participants reported working in or entering the roastery production area 

during an average work week. Four of the five production area participants reported that they 

ground coffee beans and moved roasted or ground coffee. These participants reported being 

within arm’s length of cooling bins that contain roasted beans while they are cooling. Eight 

of the nine total participants reported being within arm’s length of production hoppers, bins, 

or containers of roasted coffee other than cooling bins. 

Eight of the nine total participants reported working in the cafés. All café participants 

reported that they do not roast coffee beans inside the cafés, but they do grind coffee beans 

inside the cafés. 

Symptoms and Self-Reported Diagnoses

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

are listed in Table A6. Nose symptoms were the most commonly reported symptom (n=9, 

100%), followed by eye symptoms (n=7, 78%) and sinusitis or sinus problems (n=3, 33%). 

Two participants reported improvement in their symptoms away from the workplace. 

One employee reported that their symptoms were caused or aggravated by dust; all other 

employees did not identify a source that maybe causing or aggravating their symptoms. 

Wheeze was the most commonly reported lower respiratory symptom (n=3, 33%) (Table A6). 

None reported improvement in wheeze away from the workplace. Flu-like achiness or achy 

joints and fever or chills were the most commonly reported systemic symptom (n=6, 67%). 

Two (22%) participants reported that their systemic symptoms were better when away from 

work. 
Health Hazard Evaluation Report 2016-0109-3343 Page 17

Three participants reported a diagnosis of hay fever or nasal allergies; two reported asthma; 

two reported eczema, dermatitis or skin allergy; and one reported gastroesophageal reflux 

disease. All these conditions, except for the gastroesophageal reflux disease, were diagnosed 

prior to employment at the coffee roasting and packaging facility and cafés. No participants 

reported a diagnosis of chronic bronchitis, emphysema, COPD, bronchiolitis obliterans, 

interstitial lung disease, hypersensitivity pneumonitis, chemical pneumonitis, sarcoidosis, 

heart disease, or vocal cord dysfunction. 

Medical Tests

All spirometry tests were interpreted at normal. There were three impulse oscillometry 

tests interpreted with abnormalities: one with a possible large airways abnormality; one 

with a possible small airways abnormality, and one with possible a small and large airways 

abnormality. One exhaled nitric oxide test was interpreted as elevated. 

NHANES Comparison of Symptoms, Diagnoses, and Spirometry

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

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

comparisons to the general US population (Table A7). 

Discussion 

At the roastery production space and the two off-site retail cafés that are 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 (near coffee and espresso grinders) or 

near pour over areas. Diacetyl, 2,3-pentanedione, 2,3-hexanedione, other VOCs, and other 

chemicals such as CO and CO2 are naturally produced when coffee beans are roasted, and 

grinding the roasted coffee beans produces greater surface area for the off-gassing of these 

chemicals [Anderson et al. 2003; Akiyama et al. 2003; Daglia et al. 2007; Newton 2002; 

Nishimura et al. 2003; Raffel and Thompson 2013]. Occupational exposure to diacetyl 

and 2,3-pentanedione can cause loss of lung function and the lung disease obliterative 

bronchiolitis [NIOSH 2016]. As of the date of this report, no cases of obliterative 

bronchiolitis have been reported in coffee café workers. 

Alpha-Diketones 

Personal Air Sampling 

Five personal (all baristas, four from the uptown café, and one from the downtown café) 

full-shift air samples taken inside the three locations using standard OSHA methods were 

above the NIOSH REL for diacetyl. The highest full-shift personal exposure to diacetyl was 

13.9 ppb collected from a barista at the downtown café who ground roasted coffee beans for 

approximately 30 minutes during the full shift sampling. This elevated average exposure 

was likely due to peak exposures that occurred during grinding coffee beans combined 

with periods of lower exposures. 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 
Page 18 Health Hazard Evaluation Report 2016-0109-3343

associated with the measured levels are higher than NIOSH recommends. As described in 

the quantitative risk assessment from the NIOSH Criteria Document (Tables 5-27 and 5-34) 

[NIOSH 2016], after a 45-year working lifetime exposure to 10 ppb (a concentration lower 

than the highest concentration measured at this facility), NIOSH estimated that about 3 in 

1,000 workers would develop reduced lung function (FEV1 below the lower limit of normal). 

NIOSH predicted that 2 in 10,000 workers exposed to diacetyl at 10 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 20 ppb (a concentration higher than the highest concentration measured 

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

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

exposed to diacetyl at 20 ppb would develop more severe lung function reduction. The effects 

of a working lifetime exposure at 13.9 ppb would bebetween those for 10 ppb and 20 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 

Of the 37 full-shift area samples, six were above the NIOSH REL for diacetyl. Areas at both 

the uptown café (the counter near the grinders [7.6 ppb], the front corner window seating area 

[7.5 ppb], and the counter near the pour over area [6.5 ppb]) and the downtown café (the bar 

between the espresso grinders and the espresso machine [5.5 ppb], the bar near the pour over 

areas [5.4 ppb], and the bar between the grinders and brewers [5.4 ppb]) had air levels that 

exceeded the NIOSH REL for diacetyl. In each café, locations near café grinders and pour 

over areas had the highest diacetyl air levels; uptown café (7.6 ppb – 6.4 ppb) and downtown 

café (5.5 ppb – 5.4 ppb). We note that NIOSH RELs are intended to be directly compared to 

personal measurements; therefore, an area air sample that exceeds a NIOSH REL is only an 

indication of potential personal exposures.

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 grinding roasted coffee beans had higher air 

concentrations of diacetyl and/or 2,3-pentanedione than any other tasks. During our visit, 

using OSHA Methods 1013/1016 over two separate 15-minute sampling periods grinding 

roasted coffee tasks, in the basement at the downtown café where the cold brew was made for 
Health Hazard Evaluation Report 2016-0109-3343 Page 19

both cafés, had the highest levels of diacetyl (80.9 ppb and 124.5 ppb) and 2,3-pentanedione 

(87.4 ppb and 133.8 ppb).We also captured instantaneous evacuated canisters taskbased samples at the roastery production space during tasks of dumping, hand blending, 

and packaging coffee. We observed that hand blending two types of roasted coffee in 5 

gallon buckets resulted in the highest diacetyl (maximum 15.5 ppb) and 2,3-pentanedione 

(maximum 5.2 ppb) air concentrations compared to other tasks.

Source-Based Exposures

During the visit, instantaneous evacuated canisters source-based samples were captured at 

the downtown café in the basement at the cold brew grinder outlet and over the cold brew 

soaking vat and inside the café at the espresso grinder and espresso machine. We observed 

that at the grinder outlet and over the cold brew soaking vat in the basement resulted in the 

highest diacetyl (max 1496 ppb) and 2,3-pentanedione (max 1429 ppb) air concentrations 

compared to other tasks. Instantaneous evacuated canisters source-based samples were not 

collected at the uptown café or the roastery production space. During our visit, we observed 

that levels of CO and CO2 at each location were within the OSHA, ACGIH, and NIOSH 

personal exposure limits described in Table A1. 

Ventilation 

The personal air sampling results, supported by the area air sampling results, indicated the 

existing roastery ventilation system was effective at controlling airborne concentrations of 

alpha-diketones below the NIOSH RELs during our visit. If the amount of coffee roasted 

and packaged in the roastery increases substantially in the future, additional ventilation may 

become necessary.

An adequate supply of outdoor air, typically delivered through the HVAC system, is 

necessary in any indoor environment to dilute pollutants that are released by equipment, 

building materials, furnishings, products, and people. CO2 is a normal constituent of exhaled 

breath; thus, CO2 will also increase during building occupancy. CO2 levels are routinely 

collected in air quality studies because they can indicate whether a sufficient quantity 

of outdoor air is being introduced to an occupied space for acceptable odor control. The 

American National Standards Institute (ANSI) and ASHRAE have developed consensus 

standards and guidelines for HVAC systems. ASHRAE notes in an informative appendix 

to ANSI/ASHRAE Standard 62.1-2016: Ventilation for Acceptable Indoor Air Quality that 

indoor CO2 concentrations no greater than 700 ppm above outdoor CO2 concentrations 

will satisfy a substantial majority (about 80%) of occupants [ANSI/ASHRAE 2016]. This 

would typically correspond to indoor concentrations below 1,200 ppm since outdoor CO2

concentrations usually range between 375 to 500 ppm. However, CO2 is not an effective 

indicator of ventilation adequacy if the ventilated area is not occupied at its usual occupant 

density at the time the CO2 is measured, or if the occupancy level changes frequently over 

time, like in a café. Elevated CO2 concentrations suggest that other indoor contaminants may 

also be increased. If CO2 concentrations are elevated, the amount of outdoor air introduced 

into the ventilated space may need to be increased. 

Four of five personal sampling results from workers in the uptown café measured exposures 
Page 20 Health Hazard Evaluation Report 2016-0109-3343

to diacetyl at levels above the NIOSH REL. This clearly indicates that the existing ventilation 

system was ineffective at controlling exposures to acceptable levels, most likely because the 

existing ventilation system did not provide any fresh, outdoor air to the space. This is further 

supported by the average CO2 concentration being 1470 ppm throughout multiple days of 

sampling in the café. Concentrations of CO2 at these levels are indicative of a lack of outdoor 

air supplied to the space, and they can result in the space feeling “stale” or “stuffy.”

In some cases, building owners/managers or occupants will open doors or windows to 

increase the amount of outdoor air coming into their building. However, relying on open 

doors may cause problems. For example, the air coming into the building through the doors 

may not reach all of the occupied space. The incoming air is unfiltered and may contain 

outdoor air pollutants such as pollen and dust. Additionally, open doors may affect the 

ability of the HVAC system to adequately control temperatures and humidity. ASHRAE 

guidelines provide specific details on ventilation for acceptable indoor environmental quality. 

A ventilation system expert can help meet ASHRAE ventilation guidelines in the building. 

ANSI/ASHRAE 62.1-2016 recommends outdoor air supply rates that take into account 

people-related sources as well as building-related sources. While there are no specific 

recommendations in the standard for coffee cafés, there are several similar spaces that can 

be used as effective guidance. For restaurant dining rooms, café/fast-food dining, and bars 

and cocktail lounges, 7.5 cfm/person is recommended for people-related sources, and an 

additional 0.18 cfm for every square foot (cfm/ft2) of occupied space is recommended to 

account for building-related sources. To find rates for other indoor spaces, refer to Table 

6.2.2.1, which is found in ANSI/ASHRAE 62.1-2016 [ANSI/ASHRAE 2016]. A qualified 

ventilation contractor can help with ways to modify the existing ventilation system to bring 

in appropriate levels of outdoor air to reduce indoor alpha-diketone and CO2 concentrations 

in the uptown café. Using ASHRAE Standard 62.1-2016 as a guide, given the floor space 

of the café, roughly 300 cfm of outdoor air should be introduced to the space at maximum 

occupancy.

The personal sampling results for employees in the downtown café were all below the 

NIOSH RELs for diacetyl and 2,3-pentanedaione, except for one employee that spent a 

significant amount of time grinding coffee for cold brew in the unventilated basement of the 

building. In the main café space, the average multi-day CO2 concentration was 1178 ppm, 

which is approaching levels that would indicate a lack of appropriate outdoor air ventilation. 

This was expected since the existing ventilation system does not provide any fresh, outdoor 

air to the space. According to ASHRAE Standard 62.1-2016, roughly 300 cfm of outdoor air 

should be provided to the space continuously to meet demand at maximum occupancy.

High concentrations of alpha-diketones were measured at the basement cold brew grinder. 

Grinding coffee for cold brew in the unventilated basement of the downtown café is an issue 

that should be specifically addressed. A local exhaust ventilation (LEV) system should be 

designed and installed to capture alpha-diketones released during cold brew grinding. LEV

systems capture contaminants at the source and exhaust them before inhalation by employees 

occurs. LEV 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 
Health Hazard Evaluation Report 2016-0109-3343 Page 21

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. 

Work with a ventilation engineer to reduce alpha-diketone exposures at the cold brew grinder. 

Relocating the cold brew grinder closer to an exterior wall could make it easier to enclose the 

grinding process and reduce costs associated with ventilating the process separately. 

Medical Survey 

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

most commonly reported symptoms. One employee who works in all locations reported their 

mucous membrane symptoms were caused or aggravated by dust. 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 disease such as allergic rhinitis (hay fever, nasal allergies) and sinusitis 

are sometimes associated with lower respiratory symptoms and asthma and may 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. Two of the five participants 

that reported lower respiratory symptoms also reported nasal, sinus problems, or physiciandiagnosed hay fever or nasal allergies. 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, to prevent symptoms 

related to green coffee dust and chaff, make N-95 disposable filtering-face piece respirators 

available for voluntary use when emptying burlap bags of green beans into the roaster, 

storage containers, or cleaning the green bean storage area in the roastery production space. 

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

observed in the U.S. population. However, 56% (n=5) of participants (including participants 

with asthma) reported one or more lower respiratory symptoms in the 12 months prior to 

the medical survey. None of these participants perceived their lower respiratory symptoms 

as work-related. Asthma symptoms often improve when away from exposures that trigger 

symptoms while other lung diseases such as obliterative bronchiolitis or COPD generally do 

not improve. Spirometry can be used to help detect and follow individuals with asthma and 

other lung diseases such as obliterative bronchiolitis or COPD. Spirometry can show if air 

is exhaled from the lungs more slowly than normal (i.e. obstructive abnormality) or if the 

amount of air exhaled is smaller than normal (i.e., restrictive abnormality). In asthma, there 

is intermittent airways obstruction which is reversible after treatment with bronchodilator 

medications (e.g., albuterol). In obliterative bronchiolitis, scar tissue prevents the small 

airways (bronchioles) from opening up when albuterol is given. In other words, the airways 

are fixed and not responsive (reversible) to bronchodilator medicine. The obstructed airways 
Page 22 Health Hazard Evaluation Report 2016-0109-3343

prevent rapid emptying of the lung air sacs (alveoli) during exhalation. This explains why 

the respiratory symptoms of those with occupational obliterative bronchiolitis do not tend to 

improve when away from work-related exposures; however, avoidance of further exposure 

can stop progression of the disease [Akpinar-Elci et al. 2004]. 

Spirometry and impulse oscillometry measure different things. Spirometry assesses 

airflow 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 Assumpção et al. 2016]. For adults, there are fewer reference 

equations available for oscillometry [Vogel and Smidt 1994; Newbury et al. 2008; Schulz 

et al. 2013]. The predicted values we used for oscillometry measures were based on gender 

and age according to references values recommended by the manufacturer. Unlike predictive 

equations used for spirometry, the impulse oscillometry reference equations we used did not 

take into account height, race, or smoking status [Vogel and Smidt 1994].

We did not find any abnormalities on spirometry among the nine participants. One of the nine 

spirometry tests had a reduction in the FEV1/FVC ratio but was still within normal limits. 

However, a majority of participants reported at least one lower respiratory symptom. Impulse 

oscillometry was abnormal in three participants, and exhaled nitric oxide was elevated in 

one participant. These lower respiratory symptoms and breathing test abnormalities are not 

specific to a particular respiratory problem or disease. They could be related to workplace 

exposures or to other factors. 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 and 2,3-pentanedione that exceeded the NIOSH REL. All 
Health Hazard Evaluation Report 2016-0109-3343 Page 23

café employees, particularly those working in the uptown café and those who work in the 

basement of the downtown café, where cold brew is produced, 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, if they 

choose to share these results with the provider. In a workplace with risk of occupational lung 

disease, prevention of smoking-related lung disease is important and makes the detection of 

work-related adverse effects easier. The Centers for Disease Control and Prevention offers 

tools and resources for setting up a smoking cessation program [CDC 2018].

Conclusions 

We identified specific work tasks that resulted in air concentrations of diacetyl that exceeded 

the NIOSH REL and STEL. Five of the 13 personal air samples were above the NIOSH REL 

for diacetyl of 5 ppb. All five personal air samples with diacetyl concentrations above the 

NIOSH REL were collected on employees with primary job duties at the cafés. High fullshift and task-based diacetyl and 2,3-pentanedione exposure measurements were observed 

on café baristas and one employee who performed grinding for 30 minutes in the basement 

during full shift sampling. Areas with ground coffee present, specifically near the grinders 

in the downtown café and the cold brew soak vat in the basement had the highest levels of 

diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We observed high instantaneous levels of 

diacetyl and 2,3-pentanedione during grinding. CO levels were low at all the locations. 

The personal and area sampling results indicated the existing roastery ventilation system was 

effective at controlling airborne concentrations of alpha-diketones below the NIOSH RELs, 

at least for the amount of coffee processed during our visit. However, the ventilation systems 

in both café spaces should be modified to supply some fresh, outdoor air to the occupied 

spaces. In both cafés, supplying around 300 cfm of fresh, outdoor air would help reduce 

airborne alpha-diketone and CO2 concentrations at maximum occupancy levels. All four 

personal sampling results from employees in the uptown café and one of the five personal 

sampling results from employees at the downtown café measured exposures to diacetyl 

at levels above the NIOSH REL. Introducing fresh, outdoor air to the cafés would help 

reduce these exposures, but additional sampling for airborne diacetyl and 2,3-pentanedione 

should be conducted to ensure exposures are consistently below the REL after ventilation 

renovations are made. If exposures are still elevated, additional dilution ventilation and/or 

LEV may be required. 

Grinding coffee for cold brew in the unventilated basement of the downtown café is an issue 

that should be specifically addressed. A LEV system should be designed and installed to 

capture alpha-diketones released during cold brew grinding. Relocating the cold brew grinder 

closer to an exterior wall could make it easier to enclose the grinding process and reduce 

costs associated with ventilating the process separately.
Page 24 Health Hazard Evaluation Report 2016-0109-3343

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

most commonly reported symptoms. One employee who works in all locations reported their 

mucous membrane symptoms were caused or aggravated by dust. Wheezing or whistling in 

the chest was the most commonly reported lower respiratory symptom. All spirometry tests 

were interpreted as normal. One of nine participants had high exhaled nitric oxide, a marker 

of allergic airways inflammation. Three of nine participants had impulse oscillimetry tests 

with possible abnormalities. We recommend a medical monitoring program to identify any 

employees who may be developing lung disease (e.g., asthma, obliterative bronchiolitis) 

and to help management prioritize interventions to prevent occupational lung disease. All 

employees who work in the cafés should participate in the workplace medical monitoring 

program. 

Recommendations 

On the basis of our findings, we recommend the actions listed below. We encourage this 

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

discuss our recommendations and develop an action plan. 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. 

Engineering Controls

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

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

employees effectively without placing primary responsibility of implementation on the 

employee. 

Downtown café

1. Consult with a qualified ventilation engineer to design and install local exhaust 

ventilation around the cold brew grinder in the basement of the downtown café to 

exhaust contaminants generated during grinding directly outdoors. Consider moving 

the grinder closer to an outside wall to make the installation of LEV easier and 

cheaper. Operate the new LEV system at all times during cold brew grinding and 

brewing activities. If the new LEV system does not reduce short-term exposures 

to diacetyl and 2,3-pentanedione below the NIOSH STELs, additional dilution 

ventilation, including some fresh, outdoor air, may also be required. 

2. Work with a ventilation expert to bring in appropriate levels of outdoor air to 

meet ASHRAE ventilation guidelines into the downtown café. Using ASHRAE 

Standard 62.1-2016 as a guide, given the floor space of the cafés, roughly 300 cfm of 

fresh,outdoor air should be introduced to the space at maximum occupancy. 

3. If these engineering controls do not reduce air concentrations of alpha-diketones, work 

with a ventilation engineer to install local exhaust ventilation associated with café 

grinding tasks. 
Health Hazard Evaluation Report 2016-0109-3343 Page 25

Uptown Café

1. Work with a ventilation expert to bring in appropriate levels of outdoor air to meet 

ASHRAE ventilation guidelines into the uptown café. Using ASHRAE Standard 62.1-

2016 as a guide, given the floor space of the cafés, roughly 300 cfm of outdoor air 

should be introduced to each space at maximum occupancy. 

2. Conduct follow-up air sampling to verify that the ventilation system modifications 

have been effective in reducing CO2 levels below ASHRAE guidelines and alphadiketone exposures to below the NIOSH RELs. If diacetyl and 2,3-pentanedione 

concentrations are not maintained below the RELs, additional engineering controls 

may be necessary.

3. If these engineering controls do not reduce air concentrations of alpha-diketones, work 

with a ventilation engineer to install local exhaust ventilation associated with café 

grinding tasks. 

Roastery

1. Operate the ventilation system in the production space continuously during roastery 

operating hours. 

Administrative Controls

Administrative controls are employer-dictated work practices and policies implemented 

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.

Roastery

1. Provide an alternative method to hand-blending roasted coffee beans that minimizes 

employee contact with roasted beans during blending.

2. Eliminate the use of dry sweeping as much as possible during cleaning; particularly 

in areas where green beans are stored. Instead, use a vacuum system with a highefficiency particle air filter and wet methods whenever possible. 

Roastery & Downtown and Uptown Cafés

1. Educate employees not to place their faces right in front of or right above freshly 

ground coffee.

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

CO2, green and roasted coffee dust) in the workplace and how to protect themselves. 

OSHA’s Hazard Communication Standard, also known as the “Right to Know Law” 

[29 CFR 1910.1200] requires that employees are informed and trained on potential 

work hazards and associated safe practices, procedures, and protective measures. 

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

develop lower respiratory symptoms (e.g., cough, shortness of breath, wheezing) 
Page 26 Health Hazard Evaluation Report 2016-0109-3343

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

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

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

should share this report with their healthcare providers.

Personal Protective Equipment

The effectiveness of respiratory protection as personal protective equipment depends 

on avoiding breakdowns in implementation that can cause insufficient protection from 

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

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

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

hazard, respirators fit users and are maintained in good working order, and respirators are 

worn when they are needed. Supporting programs such as training, change-out schedules, 

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

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

engineering and administrative controls are in place. 

Basement of Downtown Café 

1. In addition to engineering and administrative controls, respiratory protection 

is an 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 or 2,3-pentanedione above their respective 

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

tasks with elevated exposures. Respirators used to reduce exposures to diacetyl 

and 2,3-pentanedione should be NIOSH-certified and equipped 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 reference, air-purifying half-face respirators 

have an APF of 10, and air-purifying full-face respirators have an APF of 50. Also, 

there are powered-air purifying respirators that have APFs of 25, 50, or 1000. The 

OSHA APFs can be found in Table 1 of OSHA Respiratory Protection Standard 

at https://www.osha.gov/pls/oshaweb/owadisp.show_document?p_id=12716&p_

table=STANDARDS. 

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), or the equivalent state standard in states with Federal OSHAapproved State Occupational Safety and Health plans. 

Roastery

1. 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 
Health Hazard Evaluation Report 2016-0109-3343 Page 27

bags of green beans, when cleaning the exhaust system of chaff, when emptying the 

chaff containers, or cleaning the green bean storage area. N95 respirators should be 

available in various sizes, and each potential N95 users should receive a copy of 

Appendix D of the OSHA Respiratory Protection Standard (or equivalent State OSHA 

Agency document) (https://www.osha.gov/laws-regs/regulations/standardnumber/191

0/1910.134AppD). 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. 

Cafés 

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

cafés. The medical monitoring should consist of evaluation with a questionnaire (to 

obtain health and work task information) and spirometry (to assess lung function) 

at baseline and at one year to monitor for respiratory symptoms and to establish 

employees’ baseline in lung function and any abnormal decline in lung function in the 

first year. Subsequently, an annual questionnaire evaluation should occur to monitor 

for respiratory symptoms. New or worsening respiratory symptoms should prompt 

additional evaluation including spirometry. Details about spirometry and a medical 

monitoring program can be found in chapter 9 of the NIOSH Criteria Document 

[NIOSH 2016]. 

2. If an employee is identified as likely having lung disease from exposure to diacetyl or 

2,3-pentanedione, it should be viewed as a sentinel event indicating that there was a 

breakdown in exposure controls and that there is potential risk for co-workers. Should 

this occur, the unanticipated source of exposure must be identified and brought under 

control. In addition, increased intensity of medical surveillance would be required for 

all employees performing similar job tasks or having similar or greater potential for 

exposure. The NIOSH Criteria Document provides detailed guidance on responses to 

such sentinel events [NIOSH 2016]. 

Smoking Cessation Program

In a workplace with risk of occupational lung disease, prevention of smoking-related lung 

disease is important and makes the detection of work-related adverse effects easier. We 
Page 28 Health Hazard Evaluation Report 2016-0109-3343

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 2018]. 
Health Hazard Evaluation Report 2016-0109-3343 Page 29

Table A1. OSHA Methods 1013/1016 full-shift personal and area air sampling results by location, 

NIOSH industrial hygiene survey, May 2017.

Analyte Sample 

Type

Work 

Location Location N

Above 

LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Above 

REL N 

(%)

Diacetyl Personal Uptown Café 4 4 (100%) 5.1 5.8 4 (100%)

Diacetyl Personal Roastery Packaging 1 1 (100%) 2.1 2.1 0 (0%)

Diacetyl Personal Roastery Production Area 2 2 (100%) 0.7 1.7 0 (0%)

Diacetyl Personal Roastery Roasting 1 1 (100%) 0.8 0.8 0 (0%)

Diacetyl Personal Downtown Café 5 5 (100%) 3.3 13.9 1 (20%)

Diacetyl Area Uptown Café 9 9 (100%) 2.4 7.6 N/A

Diacetyl Area Uptown Outside 3 1 (33%) <0.3 0.4 N/A

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

Diacetyl Area Roastery Production Area 6 6 (100%) 0.4 1.0 N/A

Diacetyl Area Roastery Roasting 2 2 (100%) 0.7 0.8 N/A

Diacetyl Area Downtown Café 12 12 (100%) 3.2 5.5 N/A

Diacetyl Area Downtown Outside 3 0 (0%) <0.3 <0.3 N/A

2,3-Pentanedione Personal Uptown Café 4 4 (100%) 6.0 6.7 0 (0%)

2,3-Pentanedione Personal Roastery Packaging 1 1 (100%) 1.3 1.3 0 (0%)

2,3-Pentanedione Personal Roastery Production Area 2 2 (100%) 0.5 1.5 0 (0%)

2,3-Pentanedione Personal Roastery Roasting 1 0 (0%) <0.5 <0.5 0 (0%)

2,3-Pentanedione Personal Downtown Café 5 5 (100%) 3.5 15.6 1 (20%)

2,3-Pentanedione Area Uptown Café 9 9 (100%) 2.8 9.0 N/A

2,3-Pentanedione Area Uptown Outside 3 1 (33%) <0.3 0.5 N/A

2,3-Pentanedione Area Roastery Outside 2 0 (0%) <0.3 <0.4 N/A

2,3-Pentanedione Area Roastery Production Area 6 3 (50%) <0.3 0.6 N/A

2,3-Pentanedione Area Roastery Roasting 2 1 (50%) <0.4 0.4 N/A

2,3-Pentanedione Area Downtown Café 12 12 (100%) 3.2 6.5 N/A

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

2,3-Hexanedione Personal Uptown Café 4 0 (0%) <0.4 <0.5 -

2,3-Hexanedione Personal Roastery Packaging 1 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Personal Roastery Production Area 2 0 (0%) <0.6 <0.6 -

2,3-Hexanedione Personal Roastery Roasting 1 0 (0%) <0.8 <0.8 -

2,3-Hexanedione Personal Downtown Café 5 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Uptown Café 9 0 (0%) <0.5 <0.5 N/A

2,3-Hexanedione Area Uptown Outside 3 0 (0%) <0.5 <0.5 N/A

2,3-Hexanedione Area Roastery Outside 2 0 (0%) <0.5 <0.6 N/A

2,3-Hexanedione Area Roastery Production Area 6 0 (0%) <0.4 <0.6 N/A

2,3-Hexanedione Area Roastery Roasting 2 0 (0%) <0.5 <0.6 N/A

2,3-Hexanedione Area Downtown Café 12 0 (0%) <0.5 <0.5 N/A

2,3-Hexanedione Area Downtown Outside 3 0 (0%) <0.5 <0.5 N/A

Note: N=number of samples; Above LOD N (%)=number and percentage of samples above limit of detection (LOD); < 

indicates below the LOD;

<= indicates less than or equal to the LOD; Above REL N=number of samples above the NIOSH recommended 

exposure limit (REL); ppb=parts

per billion; N/A indicates that NIOSH RELs are specified for personal air samples, and cannot be used for direct 

comparisons with area samples; “−” indicates that there is currently no REL for 2,3-hexanedione.

Appendix A: Tables
Page 30 Health Hazard Evaluation Report 2016-0109-3343 Table A2. OSHA Methods 1013/1016 task-based personal sampling results by location, NIOSH industrial hygiene survey, May 2017. Analyte Sample Type Work Location Task

N

Above 

LOD N 

(%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

STEL 

Comparisons 

N (%)

Above 

STEL N 

(%)

Mean 

(range) 

Sample 

Duration 

(minutes)

Diacetyl Personal Roastery Move roasted beans or ground coffee 1 1 (100%) 8.0 8.0 1 (100%) 0 (0%) 15Diacetyl Personal Roastery Package coffee 6 6 (100%) 1.2 2.8 6 (100%) 0 (0%) 15 (15–15)Diacetyl Personal Roastery Roast coffee beans 8 0 (0%) <0.9 <0.9 8 (100%) 0 (0%) 15 (15–15)Diacetyl Personal Downtown Grind coffee beans 2 2 (100%) 80.9 124.5 2 (100%) 2 (100%) 15 (15–15)

2,3-Pentanedione Personal Roastery Move roasted beans or ground coffee 1 1 (100%) 6.2 6.2 1 (100%) 0 (0%) 152,3-Pentanedione Personal Roastery Package coffee 6 3 (50%) <1.0 2.4 6 (100%) 0 (0%) 15 (15–15)2,3-Pentanedione Personal Roastery Roast coffee beans 8 0 (0%) <1.0 <1.0 8 (100%) 0 (0%) 15 (15–15)2,3-Pentanedione Personal Downtown Grind coffee beans 2 2 (100%) 87.4 133.8 2 (100%) 2 (100%) 15 (15–15)

2,3-Hexanedione Personal Roastery Move roasted beans or ground coffee 1 0 (0%) <1.4 <1.4

─

─ 15

2,3-Hexanedione Personal Roastery Package coffee 6 0 (0%) <1.4 <1.4

─

─

15 

(15–15)

2,3-Hexanedione Personal Roastery Roast coffee beans 8 0 (0%) <1.4 <1.4

─

─

15 

(15–15)

2,3-Hexanedione Personal Downtown Grind coffee beans 2 2 (100%) 2.1 2.5

─

─

15 

(15–15)

Note: N=number of samples; Above LOD N (%)=number and percentage of samples above limit of detection (LOD); < indicates below the LOD;<= indicates less than or equal to the LOD; Above STEL N (%)=number of samples above the NIOSH short‐term exposure limit (STEL); ppb=parts per billion.
Health Hazard Evaluation Report 2016-0109-3343 Page 31 Table A3. Instantaneous evacuated canister method* air sampling results by source, NIOSH survey, May 2017 Work Location Task Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) Downtown Basement cold brew grinder outlet 678 729 22.8 Downtown Basement cold brew grinder outlet 1496 1429 51.2 Downtown Basement-cold brew soaking vat 33.1 42.3 3.9 Downtown Basement-cold brew soaking vat 17.7 21.1 <0.9 Downtown Espresso grinder and espresso machine; making espresso 4.9 5.3 <1.0 Downtown Espresso grinder and espresso machine; making espresso 23.1 26.4 1.1 Note: ppb=parts per billion; < indicates below the limit of detection for the instrument used to detect 2,3-hexanedione. *Sampling duration approximately 30 seconds; source air samples were collected by placing the inlet of the canister sampler near roasted beans.
Page 32 Health Hazard Evaluation Report 2016-0109-3343 Table A4. Instantaneous evacuated canister method* air sampling results by task, NIOSH survey, May 2017 Work Location Task Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) Roastery Dumping coffee into cooling pan 1.5 0.8 <0.9 Roastery Dumping coffee into cooling pan 1.1 0.8 <1.0 Roastery Dumping coffee into cooling pan 0.6 <0.5 <0.9 Roastery Dumping coffee into cooling pan 3.1 2.5 2.2 Roastery Dumping roasted coffee beans into cooling pan <0.4 0.6 <1.0 Roastery Hand blending 2 types of roasted coffee in 5 gallon buckets 15.5 11.4 <0.9 Roastery Hand blending 2 types of roasted coffee in 5 gallon buckets 5.2 3.2 <1.0 Roastery Packaging Coffee Into 5lb Bags; Weighing 1.9 1.4 <0.9 Roastery Packaging Coffee Into 5lb Bags; Weighing 2.9 2.2 <0.9 Roastery Packaging coffee into bags; weighing 2.4 1.6 <1.0 Note: ppb=parts per billion; < indicates below the limit of detection. *Sampling duration approximately 30 seconds; task-based air samples were collected by placing the inlet of the canister sampler in the employee’s personal breathing zone as he/she performed work task to mimic exposure
Health Hazard Evaluation Report 2016-0109-3343 Page 33 Table A5. Real-time air monitoring results for carbon monoxide (CO), carbon dioxide (CO2), temperature, and relative humidity (RH), NIOSH survey, May 16-18, 2017 Relative Humidity Range verage) (A verage)(A Temperate Range °F RangeCO2verage) ppm (A CO Range verage) ppm (A eaork ArW Work Location Uptown Café Pour over area counter 0.1─4 (0.86) 705─2439 (1,480) 68.6─76.5 (72.8) 41─60.7 (46.4) Uptown Café Counters near grinder 0─3.7 (0.78) 676─4,315 (1,457) 69.4─76 (73.1) – Downtown Café Bar between Espresso Grinders and Espresso Machine 0─23.7 (0.84) 618─2,035 (1,288) 69.2─84.4 (80.6) – Downtown Café Bar between grinders and brewers 0.8─1.8 (1.13) 1,103─1,848 (1,456) 77.3─80.1 (78.6) – Dowtown Café Basement near cold brew grinders 0.0─0.9 (0.02) 549─1157 (929) 68.4─72.2 (69.0) – Roasterie Near Roaster on Table 0.3─0.8 (0.06) 510─712 (564) – – Roasterie On weighing table 0─0.9 (0.06) 452─743 (594) 74.9─78 (76.5) 52.9─70.2 (56.3) Outside Outside 0.0─3.6 (0.3) 406─522 (446.8) – – Note: NIOSH=National Institute for Occupational Safety and Health; ppm=parts per million; “–“Nothing recorded during the sampling period
Page 34 Health Hazard Evaluation Report 2016-0109-3343 Table A6. Prevalence of reported symptoms and work-relatedness, NIOSH medical survey, May 2017 Experienced in the last 4 weeks N = 9 Number (%) Experienced in the last 12 months N = 9 Number (%) Symptom Nose symptoms* 9 (100%) 6 (67%) Eye symptoms† 7 (78%) 5 (56%) Sinusitis or sinus problems 3 (33%) 1 (11%) Problem with ability to smell 2 (22%) ─ Phlegm on most days for 3 months 2 (22%) ─ Lower respiratory symptoms (reported at least one of the following) 5 (56%) 2 (22%) Chest wheezing or whistling 3 (33%) 1 (11%) SOB on level ground or walking up a slight a hill 1 (11%) ─ Breathing trouble 2 (22%) 0 Awoke with chest tightness 2 (22%) 0 Awoke with shortness of breath 1 (11%) 0 Usual cough‡ 2 (22%) 2 (22%) Asthma attack 1 (11%) 0 Systemic symptoms(reported at least one of the following) 7 (78%) 3 (33%) Flu-like achiness or achy joints 6 (67%) 3 (33%) Fever or chills 6 (67%) 2 (22%) Unusual tiredness or fatigue 4 (44%) 2 (22%) Note: NIOSH=National Institute for Occupational Safety and Health ; N=number of participants; SOB=shortness of breath; “-“= A four week question was not asked for the symptom. *Nose symptoms includes one or both of the following: 1) stuffy, itchy, or runny nose or 2) stinging, burning nose. †Eye symptoms includes one or both of the following: 1) watery, itchy eyes or 2) stinging, burning eyes. ‡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 participant 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 2016-0109-3343 Page 35

Table A7. Adjusted* comparisons of symptoms and self-reported physician diagnosis among 

NIOSH medical survey participants (N=9) to U.S. adult population, May 2017

Observed Expected SMR Health condition Comparative population† Number Number (95% CI)‡

Watery, itchy eyes last 12 months NHANES III 7 3.8 1.8 (0.9─3.8)

Stuffy, itchy, or runny nose last 12 months NHANES III 9 5.6 1.6 (0.8─3.0)

Sinus problems last 12 months NHANES III 3 3.2 0.9 (0.3─2.7)

Phlegm 3 consecutive month or more NHANES III 2 0.6 3.4 (0.9─12.6)

Wheeze last 12 months NHANES 2007-2012 3 1.4 2.1 (0.7─6.1)

Shortness of breath on exertion NHANES III 1 1.1 0.9 (0.1─4.9)

Ever asthma (physician-diagnosed)§ NHANES 2007-2012 2 0.6 3.2 (0.9─11.5)

Current asthma (physician-diagnosed)§ NHANES 2007-2012 1 0.4 2.7 (0.5─15.3)

Note: NHANES=National Health and Nutrition Examination Survey; SMR= standardized morbidity ratio.

*Adjusted for sex, race/ethnicity, age, and smoking categories. 

†We used the most recent NHANES survey available for each comparison. 

‡95% confidence intervals (CIs) that exclude one are statistically significantly different from comparison with US 

adult population and are shown in bold 

§Participants with a history of asthma reported being diagnosed prior to employment at the coffee roasting and 

packaging facility and cafés.
Page 36 Health Hazard Evaluation Report 2016-0109-3343

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Health Hazard Evaluation Report 2016-0109-3343 Page 45

Keywords: NAICS 311920 (Coffee Roasting), Pennsylvania, diacetyl, 2,3-pentanedione, 

2,3-hexanedione, coffee, carbon monoxide, carbon dioxide, volatile organic compounds 

(VOCs).
Page 46 Health Hazard Evaluation Report 2016-0109-3343

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, Kathleen Fedan, and Brian Tift

Laboratory Support: Dru Burns, Ryan LeBouf, Anand Ranpara, and Yeonmi Park

Site Visit Team Members: Tia McClelland, Randy Boylstein, Stephen Martin, and Michael 

Beaty

Availability of Report

Copies of this report have been sent to the employer and employees at the facility. The state

health department and the Occupational Safety and Health Administration Regional Office

have also received a copy. This report is not copyrighted and may be freely reproduced.

This report is available at https://www.cdc.gov/niosh/hhe/reports/pdfs/2016-0109-3343.pdf.

All other Health Hazard Evaluation Reports may be found at https://www2a.cdc.gov/hhe/

search.asp.

Recommended citation for this report:

NIOSH [2019]. Health hazard evaluation report: Evaluation of exposure and 

respiratory health at a coffee roasting and packaging facility and two off-site retail 

cafés. By McClelland T, Boylstein RJ, Martin SB, Beaty M. 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. 2016-0109-3343.
To receive documents or other information about

occupational safety and health topics, contact NIOSH

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TTY: 1-888-232-6348

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or visit the NIOSH website at http://www.cdc.gov/niosh

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