Health Hazard Evaluation Report 2016-0013-3294 Page 1

Evaluation of exposures and respiratory 

health at a coffee roasting and packaging 

facility 

Report No. 2016-0013-3294

October 2017

Brie Hawley, MS, PhD

Stephen B. Martin, Jr., PhD, PE

Matt Duling, MS

Rachel L. Bailey, DO, MPH

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 2016-0013-3294

Contents

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

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

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

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

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

Process Description............................. 4 

Methods ............................................... 5 

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

Discussion .......................................... 25

Conclusions........................................ 31

Recommendations............................. 32

Appendix A: Tables............................ 37

References.......................................... 45

Acknowledgements........................... 55

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.
Health Hazard Evaluation Report 2016-0013-3294 Page i

We evaluated respiratory health and 

potential exposures to the alphadiketones 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. 

Some employees in the production area 

of the facility had full-shift exposures 

that exceeded the NIOSH recommended 

exposure limit for diacetyl. Five 15-minute 

short-term exposure samples collected 

on employees grinding roasted coffee 

beans exceeded the NIOSH short-term 

exposure limit for diacetyl. One 15-minute 

sample collected on an employee grinding 

roasted coffee was above the short-term 

exposure limit for 2,3-pentanedione. Air 

levels of carbon monoxide exceeded 

the NIOSH ceiling limit of 200 parts 

per million in the area near the main 

grinders. Eye, nose, and sinus symptoms 

were the most commonly reported 

symptoms. Breathing trouble was the most 

commonly reported lower respiratory 

symptom followed by wheezing and chest 

tightness. All 13 spirometry tests were 

normal. Two of 13 participants had high 

exhaled nitric oxide, a marker of allergic 

airways inflammation. We recommend 

engineering controls to mitigate exposure 

to diacetyl, 2,3-pentanedione, and carbon 

monoxide near the main grinders and 

the weigh/fill machine where ground 

coffee is packaged. We also recommend 

implementing administrative controls such 

as modification of work practices, training 

employees about work-place hazards, and 

instituting a medical monitoring program.

Highlights of this Evaluation

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

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

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

roasting, grinding, and packaging.

What We Did

● We visited the coffee roasting and 

packaging facility in April 2016 and June 

2016.

● We performed an industrial hygiene survey 

at the facility in April 2016.

● We collected full-shift (hours), task 

(minutes), and instantaneous (seconds) 

air samples to measure concentrations 

of alpha-diketones. Specifically, we 

measured diacetyl, 2,3-pentanedione, and 

2,3-hexanedione over multiple days. 

● We collected roasted coffee beans 

to measure their emission potential 

for diacetyl, 2,3-pentanedione, and 

2,3-hexanedione.

● We measured real-time air levels of carbon 

monoxide, and carbon dioxide.

● We assessed the ventilation system at the 

facility.

● We administered a health questionnaire to 

employees and performed breathing tests 

in June 2016.

What We Found

● On full-shift sampling, some production 

employees were exposed to diacetyl 

concentrations above the recommended 

exposure limit of 5 parts per billion. The 

highest concentration of diacetyl we 

measured as an average across a full-shift 

was 13 parts per billion.

● Levels of diacetyl in the air during short-
Page ii Health Hazard Evaluation Report 2016-0013-3294

term sampling were higher for tasks involving grinding roasted coffee (maximum 

375 parts per billion) and packaging ground coffee at the new weigh-fill machine 

(maximum 30 parts per billion). 

● Tasks with the highest levels of diacetyl or 2,3-pentanedione were grinding, packaging 

ground coffee, and cleaning the roaster. 

● All five of the fifteen-minute samples collected on employees performing grinding of 

coffee beans exceeded the National Institute for Occupational Safety and Health shortterm exposure limit for diacetyl of 25 parts per billion.

● We observed employees hand blending roasted beans in the areas between the two 

roasters.

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

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

● Carbon dioxide levels reached as high as 2500 parts per million in the area near the 

main grinders.

● All tested roasted coffee beans emitted diacetyl and 2,3-pentanedione.

● Eye, nose, and sinus symptoms were the most commonly reported symptoms. Some 

employees reported their symptoms were caused or aggravated by green coffee bean 

dust, roasted coffee dust, bagging ground coffee, or cleaning the roaster. 

● Breathing trouble was the most commonly reported lower respiratory symptom 

followed by wheezing and chest tightness. 

● All spirometry tests (n=13) were normal. 

● Two of 13 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 the main grinders and at the new weigh-fill machine 

to capture diacetyl, 2,3-pentanedione, and carbon monoxide emissions from the main 

grinders and packaging of ground coffee.

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

monoxide, and carbon dioxide into the air.

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

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

reducing exposures to below the recommended exposure limits.

 
Health Hazard Evaluation Report 2016-0013-3294 Page iii

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

monoxide levels exceed the National Institute for Occupational Safety and Health 

ceiling limit of 200 ppm.

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

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

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

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

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

healthcare providers and to a designated individual at the workplace. 

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

What Employees Can Do

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

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

storage bins. 

● 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 for 

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

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

cleaning the green bean storage area.

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

provider(s) 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. 
Page iv Health Hazard Evaluation Report 2016-0013-3294

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Health Hazard Evaluation Report 2016-0013-3294 Page v

Abbreviations

μg Microgram

ACGIH® American Conference of Governmental Industrial Hygienists

AHU Air-handling unit

AL Action level

ANSI American National Standards Institute

APF Assigned protection factor

AX Area of reactance

CFR Code of Federal Regulations

CO Carbon monoxide

CO2 Carbon dioxide

COPD Chronic obstructive pulmonary disease

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

FEV1 Forced expiratory volume in 1 second

fpm Feet per minute

Fres Resonant frequency

FVC Forced vital capacity

HVAC Heating, ventilation, and air-conditioning

Hz Hertz

IDLH Immediately dangerous to life or health

IOS Impulse oscillometry

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

LOD Limit of detection

LOQ Limit of quantitation

LPM Liters per minute

MERV Minimum efficiency reporting value

mg/m3 Milligrams per cubic meter of air

mL Milliliter

mL/min Milliliter per minute

NHANES National Health and Nutrition Examination Survey

NIOSH National Institute for Occupational Safety and Health

OEL Occupational exposure limit

OSHA Occupational Safety and Health Administration

PEL Permissible exposure limit

ppb Parts per billion

ppm Parts per million

QC Quality control
Page vi Health Hazard Evaluation Report 2016-0013-3294

R5 Resistance at 5 Hertz

R20 Resistance at 20 Hertz

REL Recommended exposure limit

SMR Standard morbidity ratio

STEL Short-term exposure limit

TLV® Threshold limit value

TWA Time-weighted average

US United States

VOC Volatile organic compound

X5 Reactance at 5 Hertz
Health Hazard Evaluation Report 2016-0013-3294 Page vii

Mention of any company or product does not constitute endorsement by NIOSH. In 

addition, citations to websites external to NIOSH do not constitute NIOSH endorsement 

of the sponsoring organizations or their programs or products. Furthermore, NIOSH is not 

responsible for the content of these websites. All web addresses referenced in this document 

were accessible as of the publication date of this report.
Health Hazard Evaluation Report 2016-0013-3294 Page 1

Summary

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

Occupational Safety and Health received a request from management at a coffee roasting 

and packaging company. The request stated concerns about health issues related to exposure 

to diacetyl during coffee roasting, grinding, and packaging. In April 2016, we conducted an 

industrial hygiene survey and ventilation assessment at the facility. The industrial hygiene 

survey consisted of the collection of air samples and bulk samples of coffee for the analysis 

of diacetyl, 2,3-pentanedione, and 2,3-hexanedione. Continuous monitoring instruments 

were used to monitor total volatile organic compounds, carbon monoxide, carbon dioxide, 

temperature, and relative humidity in specific areas and during tasks. We returned in June 

2016 to perform a medical survey. The medical survey consisted of a health questionnaire 

and breathing tests.

Sixteen of the 27 personal full-shift air samples exceeded the NIOSH recommended exposure 

limit for diacetyl of 5 parts per billion. These sixteen personal air samples were collected 

on employees with primary job duties on the production floor. High full-shift and taskbased diacetyl and 2,3-pentanedione exposure measurements were observed on employees 

that ground coffee, packaged ground coffee, or worked in areas near ground coffee. Areas 

with ground coffee present, specifically the main grinders and new weigh-fill machine, 

consistently had the highest levels of diacetyl, 2,3-pentanedione, total volatile organic 

compounds, and carbon monoxide. We observed high instantaneous levels of diacetyl and 

2,3-pentanedione during grinding. Carbon monoxide levels near the main grinders exceeded 

the NIOSH ceiling limit of 200 parts per million. Carbon dioxide levels were low throughout 

most of the facility.

Mucous membrane symptoms, specifically eye, nose, and sinus symptoms, were the most 

commonly reported symptoms. Some employees reported their symptoms were caused or 

aggravated by green coffee bean and roasted coffee dust, bagging ground coffee, or cleaning 

the roaster. Breathing trouble was the most commonly reported lower respiratory symptom 

followed by wheezing and chest tightness. All administered spirometry tests (n=13) were 

normal. Two of 13 participants had high exhaled nitric oxide, a marker of allergic airways 

inflammation. We recommend installing local exhaust ventilation and training employees 

about workplace hazards. We also recommend 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 2016-0013-3294

Introduction

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

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

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

related to exposure to diacetyl during coffee roasting and packaging. In April 2016, we 

conducted a ventilation assessment and industrial hygiene survey at the facility. We collected 

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

including diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We also monitored and recorded 

carbon monoxide (CO), carbon dioxide (CO2

), and total VOCs. In June 2016, we conducted a 

medical survey.

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 same compounds [Akiyama et al. 2003]. Often, coffee roasting 

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

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

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

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

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

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

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

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

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

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

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

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

should be taken to reduce exposures in the workplace.

These exposure limits and the accompanying recommendations for control of exposures 

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

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

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

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

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

] 
Health Hazard Evaluation Report 2016-0013-3294 Page 3

below the 5th percentile) as a result of that exposure. NIOSH predicted that around 1 in 

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

more severe lung function reduction (FEV1

 below 60% predicted, defined as moderately 

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

time 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 currently no established 

recommended exposure limits for 2,3-hexanedione.

Carbon Monoxide and Carbon Dioxide

CO and CO2

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

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

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

and CO2 can cause headache, dizziness, fatigue, nausea, confusion, rapid breathing, impaired 

consciousness, coma, and death [Newton 2002; Nishimura et al. 2003; Langford 2005; CDC 

2013a; Raffel and Thompson 2013; Rose et al. 2017]. Occupational exposure limits for CO 

and CO2

 are listed in Table 1.

Obliterative Bronchiolitis

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

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

cough, shortness of breath on exertion, and/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 in employees at a coffee roasting and 

packaging facility that produced unflavored and flavored coffee [CDC 2013b]. A NIOSH 

health hazard evaluation at that facility found diacetyl and 2,3-pentanedione concentrations 

in the air that were concerning and identified three sources: 1) flavoring chemicals added to 

roasted coffee beans in the flavoring area; 2) grinding unflavored roasted coffee beans and 

packaging unflavored ground and whole bean roasted coffee in a distinct area of the facility, 

and 3) storing roasted coffee in hoppers for off-gassing, on a mezzanine above the grinding/

packaging process [Duling et al. 2016]. At the time of the previous health hazard evaluation, 

workers had excess shortness of breath and obstruction on spirometry, both consistent with 

undiagnosed lung disease. Respiratory illness was associated with exposure and not limited 

to the flavoring areas [Bailey et al. 2015]. However, all workers who were diagnosed with 

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

bronchiolitis have been reported in workers at coffee roasting and packaging facilities that 

produce only unflavored coffee.
Page 4 Health Hazard Evaluation Report 2016-0013-3294

Work-related Asthma

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

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

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

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

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

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

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

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

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

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

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

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

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

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

to coffee dust [Oldenburg et al. 2009].

Process Description

In April and June 2016, the coffee roasting and packaging facility had 29 employees 

consisting of 13 production and 16 administrative employees. The employees were not 

represented by a union, and there was no café onsite. The facility was located in a building 

shared with four other organizations. The coffee company also had four cafés located off 

site. At the coffee roasting and packaging facility, the production area was approximately 

10,000 square feet in size. Roughly 2000 to 3000 pounds of coffee was roasted and packaged 

per day, and approximately one-third of the coffee produced was ground coffee. The facility 

received green coffee beans in burlap bags from around the world including, but not limited 

to, Peru, Indonesia, Nicaragua, Ethiopia, Guatemala, Mexico, and Honduras. Green beans 

were stored in burlap bags and storage containers along the wall by a Diedrich roaster and 

packaging area. 

To prepare a batch for roasting, a roaster operator poured a desired amount of green coffee 

beans from the storage containers into a 5-gallon plastic bucket. The contents of the bucket 

were then dumped into the hopper at their respective roaster. The facility had two roasters. 

The Primo roaster was capable of roasting 50 pounds of coffee per batch, and the Diedrich 

could roast 150 pounds of coffee per batch. When ready, the roaster operator dropped the 

green beans into the roaster. The beans were heated to a specific temperature and for a 

specific time period for the desired roast. Time and temperature varied between different 

types of roasts. On average, roasts lasted 14-16 minutes. Occasionally, the roaster operator 

would pull a small sample of beans from the roaster to check the color and smell of the 

beans. At the end of each cycle, the roaster operator emptied the roasted beans into a cooling 

bin where they were agitated by a rotating arm. The cooling bins at both roasters utilized 

a downdraft exhaust system that pulled air downward past the roasted beans to accelerate 
Health Hazard Evaluation Report 2016-0013-3294 Page 5

cooling. The downdraft system exhausted through the roaster and then to the outside through 

a ventilation duct. The roaster operator monitored the roasting equipment throughout the 

roasting and cooling process. After cooling, the roasted beans were dispensed from the 

cooling bin of the Primo roaster into approximately 30-gallon plastic containers with lids. 

At the Diedrich roaster, the cooled beans were pulled by a siphon system through a destoner 

and then dispensed into a large plastic bin. The roaster operator then manually moved the 

plastic containers to a storage area, adjacent to the two roasters and packaging areas, until 

needed for further processing, including grinding and packaging. A quality control technician 

periodically brewed roasted coffee in a separate quality control room to assess product 

quality and taste. 

In the packaging area, orders were completed using the new or old weigh-fill machines to 

measure out either 12 ounces or 5 pounds of beans. All bags were manually packaged and 

were equipped with one-way valves for off-gassing. Whole beans were packaged using the 

old weigh-fill machine. Whole beans and ground coffee were packaged using the new weighfill machine. For ground coffee, an employee took roasted whole beans to the grinding area, 

manually emptied the coffee beans into a grinder, and then placed the packages at the bottom 

of the grinder to collect the ground coffee. The facility had two Ditting KR 1403 grinders 

capable of grinding 5 pounds of coffee per batch. A MPE GPX-WCI grinder was capable of 

grinding 40 pounds of coffee per batch. After packaging, bags of coffee were stored on open 

shelves and racks adjacent to the packaging area. Occasionally, coffee with faulty packaging 

was reworked, where the coffee was dumped from the faulty package and manually 

redirected into the packaging process for repackaging.

Every six weeks, the roasters were cleaned; accumulated chaff was removed and the exhaust 

lines from the roasters were cleaned. All employees helped disassemble the roasters and 

manually knock and scrape off the chaff from inside of the roaster and associated exhaust 

lines. 

A kitchen (breakroom) area and a small office were also located in the production floor. 

Administrative offices were located in two separate locations in the same building.

Personal Protective Equipment 

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

observed one or more employees wearing an N95 disposable filtering-facepiece respirator 

while working with green coffee beans during our survey. 

Methods

We initially visited the coffee roasting and packaging facility in April 2016. We held an 

opening meeting with management and an employee representative, collected bulk samples 

and air samples, and performed a ventilation assessment. At the conclusion of our site visit, 

we held a closing meeting with management and employees. We visited the facility again in 

June 2016 for a medical survey. 
Page 6 Health Hazard Evaluation Report 2016-0013-3294

We had the following objectives for the health hazard evaluation:

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

during coffee roasting and packaging;

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

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

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

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

5. Determine if employees had 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; 

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. For 

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

minutes, and hours. Samples collected over hours can help determine average concentrations 

that can be compared to 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 air samples over several minutes. We also conducted 

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

Air Sampling and Analysis Using Modified Occupational Safety and Health (OSHA) Methods 

1013/1016

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

2,3-hexanedione on silica gel sorbent tubes during our industrial hygiene survey. The samples 

were collected and analyzed according to the modified OSHA sampling and analytical 

Methods 1013/1016 [OSHA 2008; OSHA 2010; LeBouf and Simmons 2017]. In accordance 

with the two methods, two glass silica gel sorbent tubes were connected by a piece of tubing 

and inserted into a protective, light-blocking cover. The tubes were connected in series to a 

sampling pump pulling air through the tubes at a flow rate of 50 milliliters per minute (mL/

min). The sampling setup was attached to an employee’s breathing zone or placed in an area 

basket in various places throughout the facility. For full-shift sampling, we collected two 

consecutive 3-hour samples and calculated the time-weighted average (TWA) concentration 

from the two samples, assuming that the total 6-hour monitoring results reflected a full work 

shift (8-hour) TWA exposure. Although this may introduce some error, it is a conservative 

approach that is more protective of employees than the alternative assumption of no exposure 

during the last two hours of the shift. We refer to these samples as “full-shift samples” 
Health Hazard Evaluation Report 2016-0013-3294 Page 7

throughout this report. We also collected short-term task based samples in the same manner, 

but the sampling pump flow rate was 200 mL/min as detailed in OSHA Methods 1013 and 

1016 [OSHA 2008; 2010]. Sampling times were dependent on the duration of the task being 

performed. 

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

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

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

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

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

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

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

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

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

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

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

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

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

on the volume of air collected during the sampling period. The LODs for task samples 

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

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

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

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

Air Sampling and Analysis Using Evacuated Canisters

We collected 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. We also collected instantaneous air samples before and after the work shift to 

determine if air concentrations of alpha-diketones increased over a work shift. The evacuated 

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

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

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

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

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

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

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

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

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

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

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

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

included. At present, this canister method is partially validated [LeBouf et al. 2012] and 
Page 8 Health Hazard Evaluation Report 2016-0013-3294

not considered the standard method. The LODs were 0.78 ppb for diacetyl, 1.08 ppb for 

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

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

been collected, and they may be higher or lower than typical LOD values. 

Bulk Sampling and Headspace Analysis

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

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

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

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

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

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

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

emission potential.

Real-time (Continuous) Air Sampling

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

to measure concentrations of total VOCs in the air. The ppbRAE has a non-specific 

photoionization detector that responds to chemicals with ionization potentials below the 

energy of the lamp. This sampling was conducted to identify areas where coffee could be 

releasing total VOCs. Areas where higher concentrations of total VOCs are measured help 

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

necessary. We also collected real-time measurements of CO2

, CO, temperature, and relative 

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

Exposure Limits

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

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

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

exposures.

Occupational Safety and Health Administration (OSHA)

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

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

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

agent over a work shift [OSHA 2016]. OSHA short-term exposure limits (STELs) are the 

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

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

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

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

can be considered using available occupational exposure references and recommendations 

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

Hygienists (ACGIH®) TLVs® and NIOSH RELs.
Health Hazard Evaluation Report 2016-0013-3294 Page 9

American Conference of Governmental Industrial Hygienists (ACGIH®) 

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

published, peer-reviewed scientific literature and publishes recommendations for 

levels of substances in air based on an 8-hour workday and 40-hour workweek. These 

recommendations are called threshold limit values (TLVs®) [ACGIH® 2016]. 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® 2016]. 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® 2017]. 

National Institute for Occupational Safety and Health (NIOSH)

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

10-hour work shift, during a 40-hour workweek. [NIOSH 2010]. NIOSH also provides 

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 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® 2016]. The NIOSH REL is higher for 2,3-pentanedione than for 

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

detect 2,3-pentanedione at lower levels. In addition to the REL, NIOSH also recommends an 

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

employee exposures are routinely below the diacetyl REL. When exposures exceed the 

action level, employers should take corrective action (i.e., determine the source of exposure, 
Page 10 Health Hazard Evaluation Report 2016-0013-3294

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

NIOSH REL for diacetyl [NIOSH 2016].

Table 1. Exposure limits for compounds sampled during the NIOSH survey, April 2016.

Compound

OSHA* ACGIH® NIOSH

PEL TLV® STEL REL STEL IDLH

Diacetyl - 10 ppb 20 ppb 5 ppb† 25 ppb -

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

2,3-Hexanedione - - - - - -

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

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

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

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

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

REL=recommended exposure limit; IDLH=immediately dangerous to life or health; mg/m3=milligram 

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

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

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

day, during a 40-hour workweek.

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

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

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

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

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

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

exceeded at any time.

Ventilation Assessment

On April 7, 2016, we did a visual and physical assessment of all ventilation components 

at the facility. Physical measurements of the facility were taken with a Model DISTO 

E7100i laser-tape measure (Leica Geosystems AG, Heerbrugg, Switzerland). Ventilation 

measurements in the production space were taken using a Model EBT731 Balometer Air 

Balancing Instrument (Alnor Products, TSI Incorporated, Shoreview, MN). The make, model, 

and other key information on the air-handling unit (AHU) supplying air to the production 

space was also collected. 

NIOSH Medical Survey

Participants 

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

June 9-10, 2016. 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, 

spirometry, and if indicated the administration of a bronchodilator with repeat impulse 

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

breathing test results and recommended each participant provide the information to their 
Health Hazard Evaluation Report 2016-0013-3294 Page 11

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 2017a]. Some of the questions appeared on more than one of 

the standardized questionnaires. We also supplemented our questionnaire with additional 

respiratory and systemic symptom questions. 

Spirometry 

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

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

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

participant can forcefully blow out after taking a deep breath), 2) FEV1

 (the amount of air 

that the participant can blow out in the first second of exhaling), and 4) the ratio of FEV1

 to 

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

et al. 2005].

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

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

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

obstruction as an FEV1

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

lower limit of normal; restriction as a normal FEV1

/FVC ratio with FVC less than the lower 

limit of normal; and mixed obstruction and restriction as having FEV1

, FVC, and FEV1/FVC 

ratio all less than the lower limit of normal. We used the FEV1

 percent predicted to categorize 

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

et al. 2005]. 

Impulse Oscillometry

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

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

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

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

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

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

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

contraindication.
Page 12 Health Hazard Evaluation Report 2016-0013-3294

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

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

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

impulse oscillometry testing machine sends sound waves called pressure oscillations at 

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

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

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

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

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

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

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

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

HJ 2015]. We defined possible large (central) airways abnormality as a normal X5 and 

elevated R5 with no evidence of frequency dependence. We defined a possible small airways 

abnormality if there was evidence of frequency dependence and/or a decreased X5 with or 

without an elevated R5. We defined possible combined small (peripheral) and large (central 

airways) abnormality as a decreased X5 and elevated R5 with no evidence of frequency 

dependence.

Bronchodilator Reversibility Testing for Impulse Oscillometry and Spirometry

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

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

the airways in some individuals (e.g., asthmatics). For oscillometry, we defined reversibility 

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

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

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

administration. 

Fractional Exhaled Nitric Oxide (FeNO) 

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

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

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

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

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

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

Statistical Analysis 

Industrial Hygiene Survey and Ventilation Assessment

We performed analyses using Excel (Microsoft®, Redmond, WA) and SAS version 9.3 (SAS 

Institute, Cary, NC). We created summary statistics by work area, job title, and task. When 
Health Hazard Evaluation Report 2016-0013-3294 Page 13

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 

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

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

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

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

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

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

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

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

Results

All results tables are located in Appendix A.

Industrial Hygiene Survey 

Personal and Area Full-shift Air Sampling Results 

Personal and area full-shift air sampling results using OSHA Method 1013/1016 can be seen 

in Table A1. We collected 27 personal and 35 area full-shift air samples. Sixteen personal 

air samples collected on employees with primary job duties on the production floor were 

above the NIOSH REL for diacetyl of 5 ppb. Employees with personal air samples above the 

NIOSH REL for diacetyl perform various tasks including roasting, grinding, and packaging. 

Seven personal air samples collected on employees with primary duties in the office areas 

were below the NIOSH REL for diacetyl. No personal air samples were above the NIOSH 

REL for 2,3-pentanedione of 9.3 ppb.

Twenty-two area full-shift air samples 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 had 6-hour air levels that exceeded the NIOSH REL 

for diacetyl: Diedrich roaster (5.3 ppb - 7.7 ppb), Primo roaster (6.7 ppb – 12 ppb), main 

grinders (17 ppb – 51 ppb), new weigh-fill machine (9.7ppb -18 ppb), old weigh-fill machine 

(5.9 ppb - 6.8 ppb), finished product storage (6.7 ppb – 11 ppb), break room (5.5 ppb – 6.1 

ppb), and rework (5.1 ppb – 5.2 ppb). The highest full-shift average area samples for diacetyl 

and 2,3-pentanedione were measured near the grinders and the new weigh/fill machine.

The area near the main grinders consistently had the highest level of diacetyl each day. For 

the three days on which we collected samples, full-shift air levels of diacetyl at the main 

grinders were 17 ppb, 20 ppb, and 51 ppb, respectively. The second highest levels of diacetyl 
Page 14 Health Hazard Evaluation Report 2016-0013-3294

were consistently observed at the new weigh-fill machine. Full-shift air levels of diacetyl at 

the new weigh-fill machine were 9.7 ppb, 18 ppb, and 14 ppb, respectively. Three full-shift 

area air samples near the main grinders (9.7 ppb, 12.1 ppb, 27 ppb) were above the NIOSH 

REL for 2,3-pentanedione. 

Task-Based Air Sampling Results

Personal task air concentration results can be seen in Tables A2 and A3. We collected 58 

personal task air samples using OSHA Method 1013/1016. Task duration ranged from 3 

minutes to 86 minutes, with a median of 17 minutes. We collected personal task air samples 

while employees roasted coffee (n = 38), ground coffee (n = 9), packaged coffee (n = 10), 

and cleaned chaff from the roaster (n = 1). The highest exposures to diacetyl (375 ppb) 

and 2,3-pentanedione (219 ppb) were measured while an employee was grinding coffee 

(Tables A2). For task samples collected while employees packaged coffee, the highest 

exposures to diacetyl (29.7 ppb) and 2,3-pentanedione (20.9 ppb) were observed while an 

employee packaged ground coffee. The highest exposures to diacetyl and 2,3-pentanedione 

while employees roasted coffee were 13.2 ppb and 6.2 ppb, respectively. Diacetyl and 

2,3-pentanedione air concentrations measured when an employee cleaned chaff from the 

roaster while the roaster was not operating were 14.4 ppb and 9.2 ppb, respectively. 

All five fifteen-minute samples collected while employees ground coffee exceeded the 

NIOSH STEL of 25 ppb for diacetyl (exposures ranged from 27.4 ppb – 375.4 ppb). One 

15-minute sample collected while an employee ground coffee (219.2 ppb) was above the 

NIOSH STEL of 31 ppb for 2,3-pentanedione. None of the 15-minute samples (N=11) 

collected while employees packaged or roasted coffee exceeded the NIOSH STELs for 

diacetyl or 2,3-pentanedione.

We collected nine personal samples near the breathing zone of employees using 

instantaneous canisters (Table A3). Levels of diacetyl and 2,3-pentanedione observed in 

the breathing zone of employees using instantaneous canisters were much lower than the 

levels described above. Instantaneous samples taken at the breathing zone of employees 

while they ground coffee were 19 ppb to 28.3 ppb for diacetyl, and 10.3 ppb to10.9 ppb 

for 2,3-pentanedione. A breathing zone sample taken while an employee dumped roasted 

beans from the storage bin into the hopper had a diacetyl concentration of 24.4 ppb and a 

2,3-pentanedione concentration of 9.4 ppb. Instantaneous samples collected at the breathing 

zone of an employee while they hand blended roasted beans ranged from 6.6 ppb to 25.2 ppb 

for diacetyl and 3.4 ppb to 6.0 for 2,3-pentanedione.

Source Air Sampling Results

Instantaneous evacuated canister concentrations for diacetyl and 2,3-pentanedione can be 

seen in Table A4. Instantaneous samples were less than 30 seconds in duration. We collected 

32 source samples using evacuated canisters. 

The highest instantaneous source sample for diacetyl (20,574 ppb), and 2,3-pentanedione 

(9910 ppb) was measured at the main grinders, while an employee ground 5 pound bags of 

roasted coffee. All instantaneous samples taken near the main grinders had diacetyl levels 
Health Hazard Evaluation Report 2016-0013-3294 Page 15

greater than 100 ppb and 2,3-pentanedione levels greater than 35 ppb. The second highest 

diacetyl and 2,3-pentanedione air concentrations were observed in an air sample taken in the 

finished product storage area, near French roast bags. The instantaneous sample taken in the 

finished product storage had a diacetyl concentration of 4322 ppb and a 2,3-pentanedione 

concentration of 1389 ppb. 

Beginning and End of Day Air Sampling

We collected instantaneous samples using evacuated canisters at the end of the production 

shift on April 6, 2016, and the beginning of production on April 7. Both samples were taken 

in the center of the production floor. The beginning of day diacetyl air concentration was 

6.5 ppb and the 2,3-pentanedione air concentration was 2.5 ppb. The end of day diacetyl air 

concentration was 22.9 ppb and the 2,3-pentanedione air concentration was 22.1 ppb.

Bulk Samples and Headspace Results

Headspace results of diacetyl and 2,3-pentanedione for the bulk samples of roasted coffee 

beans can be seen in Table A5. The highest air concentration of diacetyl (9216 ppb) was 

observed in the headspace of French Roast beans that had been roasted in the Diedrich 

Roaster. The highest air concentration of 2,3-pentanedione (6853 ppb) was observed in the 

headspace of decaffeinated beans that had been roasted in the Diedrich Roaster.

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

Organic Compounds (VOCs)

The real-time total VOCs, CO, and CO2

, monitoring results near the roasters on April 5, 2016 

can be seen in Figures 1 through 6. Total VOC levels increased steadily in the morning while 

roasting was occurring, at both roasters. Peak levels of total VOCs and CO were much higher 

at the Primo roaster than at the Diedrich roaster. A peak total VOC level of 2561 ppm was 

observed at the Primo roaster (11:55am); whereas, the peak total VOC level observed at the 

Diedrich roaster was 1126 ppm (12:38pm). A maximum concentration of 62.5 ppm CO was 

observed at the Primo roaster (3:03pm); whereas, the CO maximum at the Diedrich roaster 

was 8.8 ppm (12:38pm). The average CO levels observed at the Primo and Diedrich roaster 

were 5.8 ppm and 1.7 ppm, respectively. The average CO2

 levels observed at the Primo and 

Diedrich roaster were 660 ppm and 640 ppm, respectively. 

We noted that the Primo roaster was in close proximity to the main grinders. Although we 

did not have a log of each time the grinders were used, we did observe that the main grinders 

near the Primo roaster were in use at 11:28 a.m.; this roughly corresponds with a peak of total 

VOCs and CO observed at the roaster at that time. 
Page 16 Health Hazard Evaluation Report 2016-0013-3294

0

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9:25 AM9:45 AM

10:05 AM10:25 AM10:45 AM11:05 AM11:25 AM11:45 AM12:05 PM12:25 PM12:45 PM

1:05 PM1:25 PM1:45 PM2:05 PM2:25 PM2:45 PM3:05 PM3:25 PM

Total VOCs (ppb)

Figure 1. Real-time monitoring results of total VOC concentrations near the Primo Roaster, 

NIOSH survey, April 5, 2016.

Figure 2. Real-time monitoring results of total VOC concentrations near the Diedrich 

Roaster, NIOSH survey, April 5, 2016.

0

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9:25 AM9:45 AM

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Total VOCs (ppb)
Health Hazard Evaluation Report 2016-0013-3294 Page 17

0

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10:19 AM10:39 AM10:59 AM11:19 AM11:39 AM11:59 AM12:19 PM12:39 PM12:59 PM

1:19 PM1:39 PM1:59 PM2:19 PM2:39 PM2:59 PM3:19 PM

CO (ppm)

Figure 3. Real-time monitoring results of CO concentrations near the Primo Roaster, NIOSH 

survey, April 5, 2016.

0

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10:19 AM10:39 AM10:59 AM11:19 AM11:39 AM11:59 AM12:19 PM12:39 PM12:59 PM

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CO (ppm)

Figure 4. Real-time monitoring results of CO concentrations near the Diedrich Roaster, 

NIOSH survey, April 5, 2016. 
Page 18 Health Hazard Evaluation Report 2016-0013-3294

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10:19 AM10:39 AM10:59 AM11:19 AM11:39 AM11:59 AM12:19 PM12:39 PM12:59 PM

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CO

2 (ppm)

Figure 5. Real-time monitoring results of CO2 concentrations near the Primo Roaster, 

NIOSH survey, April 5, 2016.

0

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10:19 AM10:39 AM10:59 AM11:19 AM11:39 AM11:59 AM12:19 PM12:39 PM12:59 PM

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CO

2 (ppm)

Figure 6. Real-time monitoring results of CO2 concentrations near the Diedrich Roaster, 

NIOSH survey, April 5, 2016.
Health Hazard Evaluation Report 2016-0013-3294 Page 19

Real-time total VOC, CO, and CO2 monitoring results near the main grinders on April 6, 

2016 can be seen in Figures 7, 8, and 9, below. CO and CO2

 levels corresponded to the total 

VOC levels, with peak levels occurring when the grinders were in use (Figures 7-9). The 

highest overall levels of total VOCs, CO, and CO2

 were observed at the main grinders when 

employees were using the grinders to grind coffee. The average CO level observed by the 

main grinders was 17.6 parts per million (ppm), with a maximum of 436 ppm occurring 

around 9:25am. A maximum total VOC concentration of 18,696 ppm was reached around the 

same time. The average total VOC level was 1326 ppm. Of the 6.9 hours that we monitored 

CO levels near the main grinders on April 6, 2016, levels of CO exceeded the NIOSH ceiling 

of 200 ppm, 1.2% of the time. The average CO2

 concentration observed at the main grinders 

was 699 ppm, with a maximum of 2573 ppm occurring around 9:22 am. When the maximum 

CO, CO2

, and total VOC concentrations were observed, two employees were using the 

Ditting 5 pound grinders. 

0

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7:55 AM8:15 AM8:35 AM8:55 AM9:15 AM9:35 AM9:55 AM

10:15 AM10:35 AM10:55 AM11:15 AM11:35 AM11:55 AM12:15 PM12:35 PM12:55 PM

1:15 PM1:35 PM1:55 PM2:15 PM2:35 PM

Total VOCs (ppb)

Two employees using 

both 5 lb grinders

Figure 7. Real-time monitoring results of total VOCs near the main grinders, NIOSH survey, 

April 6, 2016.
Page 20 Health Hazard Evaluation Report 2016-0013-3294

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7:55 AM8:15 AM8:35 AM8:55 AM9:15 AM9:35 AM9:55 AM

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1:15 PM1:35 PM1:55 PM2:15 PM2:35 PM

CO (ppm)

Two employees using 

both 5 lb grinders

Figure 8. Real-time monitoring results of CO near the main grinders, NIOSH survey, April 6, 

2016.

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3000

7:58 AM8:18 AM8:38 AM8:58 AM9:18 AM9:38 AM9:58 AM

10:18 AM10:38 AM10:58 AM11:18 AM11:38 AM11:58 AM12:18 PM12:38 PM12:58 PM

1:18 PM1:38 PM1:58 PM2:18 PM2:38 PM

CO

2 (ppm)

Two employees using 

both 5 lb grinders

Figure 9. Real-time monitoring results for CO2 air levels near the main grinders, NIOSH 

survey, April 6, 2016.

Levels of total VOCs, CO, and CO2

 observed at the new weigh-fill machine on April 6, 2016 

can be seen in Figures 10, 11, and 12. Peak total VOC and CO concentrations were reached 
Health Hazard Evaluation Report 2016-0013-3294 Page 21

in the afternoon. A maximum of 8372 ppb total VOCs and 24 ppm CO was measured at the 

new weigh-fill machine at 12:15 p.m. 

0

1000

2000

3000

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7000

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9000

7:57 AM8:17 AM8:37 AM8:57 AM9:17 AM9:37 AM9:57 AM

10:17 AM10:37 AM10:57 AM11:17 AM11:37 AM11:57 AM12:17 PM12:37 PM12:57 PM

1:17 PM1:37 PM1:57 PM2:17 PM2:37 PM

Total VOCs (ppb)

Figure 10. Real-time monitoring results for total VOCs concentrations near the new weighfill machine, NIOSH survey, April 6, 2016.

0

5

10

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7:57 AM8:17 AM8:37 AM8:57 AM9:17 AM9:37 AM9:57 AM

10:17 AM10:37 AM10:57 AM11:17 AM11:37 AM11:57 AM12:17 PM12:37 PM12:57 PM

1:17 PM1:37 PM1:57 PM2:17 PM2:37 PM

CO (ppm)

Figure 11. Real-time monitoring results for CO concentrations near the new weigh-fill 

machine, NIOSH survey, April 6, 2016.
Page 22 Health Hazard Evaluation Report 2016-0013-3294

0

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7:57 AM8:17 AM8:37 AM8:57 AM9:17 AM9:37 AM9:57 AM

10:17 AM10:37 AM10:57 AM11:17 AM11:37 AM11:57 AM12:17 PM12:37 PM12:57 PM

1:17 PM1:37 PM1:57 PM2:17 PM2:37 PM

CO2 (ppm)

Figure 12. Real-time monitoring results for CO2 concentrations near the new weigh-fill 

machine, NIOSH survey, April 6, 2016.

Real-time monitoring results of total VOCs, CO, and CO2

 levels near the main grinders on 

April 7, 2016 can be seen in Figures 13, 14, and 15. Although we did not record each time 

the main grinders were used, we did note that the large Ditting grinder was in use at 9:50 a.m. 

and 2:20 p.m.; this corresponds with peaks of approximately 14,000 ppb total VOCs and 280-

380 ppm CO. On April 7, 2016, the average total VOC (1826 ppm), CO (38.4 ppm), and CO2 

(744 ppm) levels observed at the main grinders were higher than the day prior.

Figure 13. Real-time monitoring results of total VOCs near the main grinders, NIOSH 

survey, April 7, 2016. Monitors were placed on the left (black) and right (grey) of the main 

grinders.

0

2000

4000

6000

8000

10000

12000

14000

16000

8:48 AM9:08 AM9:28 AM9:48 AM

10:08 AM10:28 AM10:48 AM11:08 AM11:28 AM11:48 AM12:08 PM12:28 PM12:48 PM

1:08 PM1:28 PM1:48 PM2:08 PM2:28 PM2:48 PM3:08 PM

Total VOCs (ppb)
Health Hazard Evaluation Report 2016-0013-3294 Page 23

0

50

100

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8:51 AM9:11 AM9:31 AM9:51 AM

10:11 AM10:31 AM10:51 AM11:11 AM11:31 AM11:51 AM12:11 PM12:31 PM12:51 PM

1:11 PM1:31 PM1:51 PM2:11 PM2:31 PM2:51 PM

CO (ppm)

Figure 14. Real-time monitoring results of CO levels near the main grinders, NIOSH survey, 

April 7, 2016. Monitors were placed on the left (black) and right (grey) of the main grinders.

0

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1000

1500

2000

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8:51 AM9:11 AM9:31 AM9:51 AM

10:11 AM10:31 AM10:51 AM11:11 AM11:31 AM11:51 AM12:11 PM12:31 PM12:51 PM

1:11 PM1:31 PM1:51 PM2:11 PM2:31 PM2:51 PM

CO

2 (ppm)

Figure 15. Real-time monitoring results of CO2 levels near the main grinders, NIOSH survey, 

April 7, 2016. Monitors were placed on the left (black) and right (grey) of the main grinders.
Page 24 Health Hazard Evaluation Report 2016-0013-3294

Ventilation Assessment 

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

that are partitioned with partial walls, is served by a single Lennox (Dallas, TX) Model 

LGA088SH1G Packaged Cooling and Gas Heat AHU mounted on the roof of the facility. 

The AHU was equipped with four Glasfloss (Desoto, TX) Z-Line Series 18-inch × 20-

inch × 2-inch pleated air filters. The Glasfloss filters have a published ASHRAE Minimum 

Efficiency Reporting Value (MERV) of 10, which relates to filter efficiency. A MERV 10 filter 

corresponds to a removal efficiency of better than 80% for 3.0 to 10 micrometer particles and 

better than 50% for 1.0 to 3.0 micrometer particles [ANSI/ASHRAE 2017]. MERV 10 filters 

are better than MERV 8 filters that are the minimum requirement for AHUs providing air to 

occupied spaces according to ASHRAE [ANSI/ASHRAE 2017]. The filters in place during 

the NIOSH visit were clean and sized appropriately for the AHU.

The AHU was providing some amount of fresh, outdoor air to the occupied space during 

our visit, but we did not have equipment that allowed us to measure the amount. One return 

duct from the production space led to the AHU. Air from the production space was pulled 

through the return duct into the AHU, where it mixed with some outdoor air, passed through 

the MERV 10 filters and was then heated or cooled, as necessary. Once the air was tempered, 

it was pushed back into the production space through a network of round, galvanized ducts to 

eight terminal circular diffusers. The total supply air flow through the AHU was measured to 

be 1595 cubic feet per minute.

In addition to the fresh, outdoor air supplied by the mechanical ventilation system, there 

were two 18-inch circular, passive makeup air ducts that allowed additional fresh air into the 

space. These ducts were located on the eastern wall with the windows, behind the roasters. 

The amount of fresh air brought into the space through these ducts is dependent on the 

outdoor weather conditions, the windows being opened or closed, and, most importantly, the 

various operating modes of the roasters during a complete roasting cycle and each mode’s 

individual air flow requirements. 

Medical Survey 

Demographics

Thirteen of 29 employees (45%) at the coffee roasting and packaging facility participated in 

the medical survey, including nine of 13 production employees. The majority of participants 

was male (54%) and Caucasian (85%). The mean age of the participants was 34 years (range 

22-45 years), and average tenure at the company was 4 years (range: 1 year – 10 years). 

Seven of the 13 participants worked at one of the company’s café locations or in the coffee 

industry (e.g., barista, production) prior to working at this facility. Eight (62%) participants 

were current or former smokers. 

All 13 participants reported working or entering the production area, ranging from two hours 

to 40 hours a week. All reported being within an arm’s length of roasted coffee in one or 

more areas of the production process. Nine of 13 participants worked in the production area 

while some of the other participants occasionally assisted with production activities on an as 

need basis. 
Health Hazard Evaluation Report 2016-0013-3294 Page 25

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=11, 

85%), followed by eye symptoms (n=10, 77%) and sinusitis or sinus problems (n=6, 46%). 

Seven participants noted that their mucous membrane symptoms were caused or aggravated 

by green coffee bean and roasted coffee dust, bagging ground coffee, or cleaning the roaster. 

Eight (62%) participants reported one or more lower respiratory symptoms in the past 12 

months: regular trouble breathing, woken by shortness of breath, woken with chest tightness, 

wheeze or whistling in chest, attack of asthma, or shortness of breath on level ground or 

walking up a slight hill (Table A6). Breathing trouble was the most commonly reported 

lower respiratory symptom (n=5, 38%) followed by chest wheezing or whistling (n=4, 31%) 

and awoke with chest tightness (n=4, 31%). Three of the eight reported improvement in one 

or more of their symptoms when away from the workplace. Four of the eight were former 

smokers. 

Eleven (85%) participants reported one or more systemic symptoms. Flu-like achiness or 

achy joints (n=6, 46%) and fever or chills (n=6, 46%) were the most commonly reported 

systemic symptoms. Three (23%) participants reported that one or more of their systemic 

symptoms improved away from work; some participants reported that green coffee, 

green coffee or roasted coffee dust, or burnt particulates from the roaster aggravated their 

symptoms. 

Four participants reported a diagnosis of hay fever or nasal allergies; five participants 

reported a lung condition including four with a history of asthma. All these conditions were 

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

reported a diagnosis of bronchiolitis obliterans, interstitial lung disease, hypersensitivity 

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

gastroesophageal reflux. 

Medical Tests

All 13 spirometry tests were normal. One impulse oscillometry test in a never smoker was 

interpreted as consistent with a possible small airway abnormality with improvement after 

bronchodilator. Two exhaled nitric oxide tests were 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 coffee roasting and packaging facility that is the subject of this report, the highest 

area samples for total VOCs, CO, diacetyl, and 2,3-pentanedione were observed in areas 
Page 26 Health Hazard Evaluation Report 2016-0013-3294

where coffee was ground (near the main grinders) or ground coffee was present (near the new 

weigh-fill machine). Diacetyl, 2,3-pentanedione, 2,3-hexanedione, other VOCs, and other 

compounds such as CO2

 and CO are naturally produced when coffee beans are roasted, and 

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

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

Nishimura et al. 2003; Raffel and Thompson 2013]. 

Alpha-Diketones 

Personal Air Sampling 

Sixteen personal (five roaster operator, nine production, and two production manager 

employee measurements) full-shift air samples taken inside the facility using standard 

OSHA methods were above the NIOSH REL for diacetyl. The highest personal full-shift air 

samples (12-13 ppb) were collected on employees with grinding and/or packaging duties. 

No personal air samples were above the NIOSH REL for 2,3-pentanedione. As noted earlier, 

the REL should be used as a guideline to indicate when steps should be taken to reduce 

exposures in the workplace. The risks associated with the measured levels are higher than 

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

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

to 10 ppb (a concentration slightly lower than the highest concentration measured at this 

facility), NIOSH estimated less than 2 in 1,000 workers would develop reduced lung function 

(FEV1 below the 5th percentile). NIOSH predicted that around 2 in 10,000 workers exposed 

to diacetyl at 10 ppb would develop more severe lung function reduction (FEV1 below 60% 

predicted, defined as moderately severe by the American Thoracic Society [Pellegrino et al. 

2005]). After a 45-year working lifetime exposure to 20 ppb (a concentration slightly higher 

than the highest concentration measured at this facility), NIOSH estimated that 3 in 1,000 

workers would develop reduced lung function (FEV1 below the 5th percentile). 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 ppb would be 

between 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 

Areas near the Diedrich roaster, Primo roaster, main grinders, new weigh-fill machine, old 

weigh-fill machine, finished product storage, break room, and rework had air levels that 

exceeded the NIOSH REL for diacetyl. Of the 35 full-shift area samples, 22 were above the 

NIOSH REL for diacetyl. Areas where coffee was ground had the highest diacetyl (16.8-51.1 

ppb) and 2,3-pentanedione (9.7-26.7 ppb) air levels. 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 
Health Hazard Evaluation Report 2016-0013-3294 Page 27

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

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

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

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

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

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

higher exposures to diacetyl and 2,3-pentanedione. 

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

diacetyl and/or 2,3-pentanedione than other tasks. The highest exposures to diacetyl (375 

ppb) and 2,3-pentanedione (219 ppb) were measured while an employee ground coffee (Table 

A2). The greater surface area for off-gassing that is produced during grinding could have 

resulted in the higher air concentrations [Akiyama et al. 2003]. Five fifteen-minute samples 

collected while employees ground coffee exceeded the NIOSH STEL for diacetyl. One of 

the fifteen-minute air samples collected while an employee ground coffee was also above the 

NIOSH STEL for 2,3-pentanedione. We also measured higher exposures to diacetyl (29.7 

ppb) and 2,3-pentanedieone (20.9 ppb) during packaging coffee. 

The highest exposures to diacetyl and 2,3-pentanedione while employees roasted coffee were 

13.2 ppb and 6.2 ppb, respectively. Diacetyl and 2,3-pentanedione concentrations while an 

employee cleaned chaff from the roaster were 14.4 ppb and 9.2 ppb, respectively. Although 

the Primo roaster is smaller than the Diedrich roaster and processes less total volume of 

roasted beans than the Diedrich roaster, levels of diacetyl and 2,3-pentanedione as well as 

total VOCs and CO were consistently higher near the Primo roaster. The main grinders are in 

close proximity to the Primo roaster, and emissions of diacetyl, 2,3-pentanedione, total VOCs 

and CO from the main grinders may have contributed to the higher levels observed at the 

Primo roaster.

Instantaneous Sampling

We measured diacetyl and 2,3-pentanedione using instantaneous sampling, in which 

sample duration was less than 30 seconds. These instantaneous samples were collected to 

identify and describe tasks and point sources of diacetyl and 2,3-pentanedione. The highest 

instantaneous source sample for diacetyl (20,574 ppb), and 2,3-pentanedione (9911) was 

measured at the main grinders, while an employee was grinding coffee for 5 pound bags. All 

instantaneous samples taken near the main grinders had diacetyl levels greater than 100 ppb, 

and 2,3-pentanedione levels greater than 35 ppb. Levels of diacetyl and 2,3-pentanedione 

observed in the breathing zone of employees using instantaneous canisters were much 

lower for diacetyl (19 ppb-28.3 ppb), and 2,3-pentanedione (10.3 ppm-10.9 ppm). The 

second highest instantaneous sample for diacetyl and 2,3-pentanedione were observed in a 

sample taken in the finished product storage area, near French roast bags. The instantaneous 

sample taken in the finished product storage had a diacetyl concentration of 4322 ppb and 

a 2,3-pentanedione concentration of 1389 ppb. We did not take note of other tasks being 

performed in the vicinity of the storage area; it is possible that coffee was being ground or 

ground coffee was being packaged at the same time the instantaneous sample was taken. 

Instantaneous samples of diacetyl and 2,3-pentanedione taken while workers were handling 
Page 28 Health Hazard Evaluation Report 2016-0013-3294

roasted whole beans were much lower. A breathing zone sample taken while an employee 

dumped roasted beans from the storage bin into the hopper had a diacetyl concentration of 

24.4 ppb and a 2,3-pentanedione concentration of 9.4 ppb. Instantaneous samples collected 

at the breathing zone of an employee while they hand blended roasted beans were anywhere 

from 6.6 to 25.2 ppb for diacetyl and 3.4 ppb to 6.0 ppb for 2,3-pentanedione.

Our instantaneous samples collected at the end of the day on April 6, 2016 and at the 

beginning of production on April 7, 2016 indicated that background levels of diacetyl may 

remain elevated even when production activities have ceased overnight. Both samples 

were taken in the center of the production floor. The end of day diacetyl air concentration 

on April 6, 2016 was 22.9 ppb, and the 2,3-pentanedione air concentration was 22.1 ppb. 

The beginning of day diacetyl air concentration on April 7, 2016 was 6.5 ppb and the 

2,3-pentanedione air concentration was 2.5 ppb. Whole or ground coffee that is off gassing 

from bags stored in the finished product storage area combined with elevated air levels of 

alpha diketones from the production activities like grinding and packaging ground coffee 

without sufficient ventilation to remove alpha diketones may have contributed to the elevated 

levels of diacetyl even after production activities have ceased.

Bulk samples

Diacetyl is not found in green coffee beans. Rather, diacetyl is generated later in the coffee 

roasting process [Daglia et al. 2007]. As expected, we found that roasted coffee emits alphadiketones into the headspace of sealed vessels, indicating that roasted coffee is a considerable 

source of alpha-diketones in the facility. The amount of time beans were roasted, and the 

amount of time roasted beans off-gassed prior to the collection of bulk samples could be 

responsible for differences in headspace analysis results. 

Real-time Sampling for CO, CO2, and VOCs

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

were observed at the main grinders when employees were using the grinders to grind coffee. 

As noted earlier, lower emissions were also noted from the roasters.

None of the average area levels of CO exceeded the NIOSH REL (35 ppm) or OSHA PEL 

(50 ppm). However, of the 6.9 hours that we monitored CO levels near the main grinders on 

April 6, 2016, levels of CO exceeded the NIOSH ceiling (200 ppm) 1.2% of the time. The 

NIOSH ceiling limit should not be exceeded at any time. The average CO2

 concentration 

observed at the main grinders was 699 ppm, with a maximum of 2573 ppm, which was below 

the NIOSH REL (5,000 ppm) and OSHA PEL (5,000 ppm). 

One limitation of interpreting real-time measurements for VOCs, CO2

, or CO is that the 

results can only be summarized within the context of when tasks were documented. Increases 

in VOCs, CO2

, or CO may be explained by another task that occurred but was not captured 

in our notes. For example, activity at the nearby grinders may have contributed to the peak 

levels of CO and total VOCs observed at the new-weigh fill machine, but we were not able to 

note all tasks being performed and in the vicinity of the real-time monitors for the entirety of 

the day.
Health Hazard Evaluation Report 2016-0013-3294 Page 29

Ventilation

We observed that fresh, outdoor air supplied to the production space was delivered by the 

rooftop AHU, but also through inconsistent passive air transfer. Passive air transfer is largely 

dependent on weather conditions and operating parameters of the roasters. An adequate 

supply of outdoor air, typically delivered through the heating, ventilation, and air-condition 

(HVAC) system, is necessary in any occupied spaces to dilute pollutants that are released 

by equipment, processes, products, and people. We were unable to accurately measure the 

amount of fresh, outdoor air being provided by the rooftop AHU to the production space. The 

outdoor air supply may be sufficient, at least during certain parts of the year. If the amount of 

outdoor air supplied to the space is low, however, increasing the outdoor air flow will provide 

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

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

to diacetyl and 2,3-pentanedoine below the NIOSH RELs, but it is an inexpensive, easy 

place to start engineering control improvements. The existing AHU is capable of providing 

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

may be necessary. Providing more outdoor air flow will enhance dilution and removal of 

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

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

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

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

by employees.

Medical Survey 

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

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

membrane symptoms were caused or aggravated by green and roasted coffee dust, bagging 

ground coffee, and cleaning the roaster. 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. Six of the eight participants that 

reported lower respiratory symptoms also reported nasal, sinus problems and/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, make N95 disposable filtering-face piece respirators available 
Page 30 Health Hazard Evaluation Report 2016-0013-3294

for voluntary use when emptying burlap bags of green coffee beans into storage containers or 

cleaning the green bean storage area.

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

observed in the U.S. population. However, 62% of participants reported one or more 

lower respiratory symptoms in the 12 months prior to the medical survey. Three reported 

improvement in one or more of their lower respiratory symptoms when away from the 

workplace. Asthma symptoms often improve when away from exposures that trigger 

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

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

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

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

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

is intermittent airways obstruction which is reversible after treatment with bronchodilator 

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

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

are fixed and not responsive (reversible) to bronchodilator medicine. The obstructed airways 

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

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

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

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

Spirometry and impulse oscillometry measure different things. Spirometry assesses 

airflow and is the breathing test typically used to screen for flavoring-related lung disease. 

Impulse oscillometry accesses the airways response to a sound or pressure wave and has 

not commonly been used to screen for flavoring-related lung disease. In general, during 

the impulse oscillometry test, a small pressure impulse (sound wave) is imposed upon the 

inspiratory and expiratory airflow during normal tidal breathing. This pressure wave causes 

a disturbance in the airflow and pressure, and the response of the airways (i.e., change in 

pressure to change in flow) is a measure of the resistance to airflow in the airways [Desiraju 

and Agrawal 2016]. Impulse oscillometry may be useful as an indirect measure of airflow 

obstruction and helpful in individuals not able to perform forced breathing maneuvers that 

are required during the spirometry test. The impulse oscillometry test has been used for many 

years to measure changes in the airways of children with lung problems such as asthma 

and cystic fibrosis [Song et al. 2008; Komarow et al. 2011; Shi et al. 2012; Schulze et al. 

2016]. More recently, impulse oscillometry has been used to investigate lung problems in 

adults exposed to dust or chemicals, such as World Trade Center emergency responders and 

soldiers returning from deployment overseas [Oppenheimer et al. 2007; Berger et al. 2013; 

Weinstein et al. 2016]. Over the years, researchers have developed reference (predictive) 

equations for different populations of children for oscillometry [Malmberg et al. 2002; Park 

et al. 2011; Lee et al. 2012; de Assumpcão et al. 2016]. For adults, there are fewer reference 

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

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

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

equations used for spirometry, the impulse oscillometry reference equations we used did not 
Health Hazard Evaluation Report 2016-0013-3294 Page 31

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

We did not find any abnormalities on spirometry among the 13 participants. However, a 

majority of participants reported at least one lower respiratory symptom, in some cases 

with a work-related pattern. Impulse oscillometry was abnormal in one participant, and 

exhaled nitric oxide was elevated in two participants. 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 that exceeded the NIOSH REL. All production employees 

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

storage bins/containers of roasted coffee, grinding, weighing, or packaging coffee) should 

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

is a means of early identification of employees who may be developing lung disease 

(e.g., asthma, obliterative bronchiolitis) and can help prioritize interventions to prevent 

occupational lung disease. The NIOSH medical survey results can serve as a baseline 

for employees who participated. In a workplace with risk of occupational lung disease, 

prevention of smoking-related lung disease is important and makes the detection of workrelated adverse effects easier. The Centers for Disease Control and Prevention offers tools and 

resources for setting up a smoking cessation program [CDC 2017b].

Conclusions 

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

the NIOSH REL and STEL for diacetyl. Sixteen of the 27 personal full-shift air samples were 

above the NIOSH REL for diacetyl of 5 ppb. All sixteen personal air samples with diacetyl 

concentrations above the NIOSH REL were collected on employees with primary job 

duties on the production floor. High full-shift and task-based diacetyl and 2,3-pentanedione 

exposure measurements were observed on employees that ground coffee, packaged ground 

coffee, or worked in areas near ground coffee. Areas with ground coffee present, specifically 

the main grinders and new weigh-fill machine consistently had the highest levels of diacetyl, 

2,3-pentanedione, 2,3-hexanedione, total VOCs, and CO. We observed high instantaneous 

levels of diacetyl and 2,3-pentanedione during grinding. CO2

 levels were low throughout 

most of the facility. However, CO levels near the main grinders exceeded the NIOSH ceiling 

limit of 200 ppm.

Fresh, outdoor air was supplied to the production space by the rooftop AHU, but also through 
Page 32 Health Hazard Evaluation Report 2016-0013-3294

inconsistent passive air transfer. We were unable to measure the amount of fresh, outdoor air 

supplied to the space. The outdoor air supply may be sufficient, at least during certain parts 

of the year. If the amount of outdoor air supplied to the space is low, however, increasing 

the outdoor air flow will provide more dilution and removal of airborne contaminants from 

the space. Consistently supplying the production space with appropriate outdoor air may 

still not bring all personal exposures to diacetyl and 2,3-pentanedoine below the NIOSH 

RELs. Regardless, working with a ventilation engineer to optimize outdoor air delivery is a 

relatively inexpensive, easy place to start engineering control improvements, as the existing 

AHU is likely capable of providing more outdoor air flows with only minor adjustments 

(if any). Additionally, installing a local exhaust ventilation system around the grinders to 

immediately remove alpha-diketones produced during that operation could make noticeable 

reductions in overall concentrations.

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

the most commonly reported symptoms. Some employees reported their symptoms were 

caused or aggravated by green coffee bean and roasted coffee dust, bagging ground coffee, 

or cleaning the roaster. Breathing trouble was the most commonly reported lower respiratory 

symptom followed by wheezing and chest tightness. All administered spirometry tests were 

normal. Two of 13 participants had high exhaled nitric oxide, a marker of allergic airways 

inflammation; one participant had an impulse oscillimetry test interpreted as consistent with 

possible small airways abnormality with improvement after bronchodilator. 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 production workers and employees that assist with 

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

coffee, grinding, weighing, or packaging coffee) should participate in the workplace medical 

monitoring program.

Recommendations 

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

coffee processing facility to use a labor-management health and safety committee or working 

group to discuss our recommendations and develop an action plan. 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. 
Health Hazard Evaluation Report 2016-0013-3294 Page 33

1. Consult with a ventilation engineer for local exhaust ventilation.

2. Install local exhaust ventilation at the grinders.

3. Install local exhaust ventilation at the new weigh/fill machine.

4. Consider relocating the grinders to an area with little or no bystander foot traffic to

minimize potential exposure risks to employees not directly using the grinder.

Administrative Controls

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

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

commitment and employee acceptance. Regular monitoring and reinforcement are necessary 

to ensure that policies and procedures are followed consistently.

1. Install a CO monitor and alarm near the main grinders that can alert employees when

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

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

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

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

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

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

diacetyl and 2,3-pentanedione may fluctuate from day to day based on production

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

over multiple days.

3. Whenever possible, employees should avoid spending time in the immediate area

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

4. Whenever possible, do not blend roasted beans by hand. Instead, use some other

automatic mechanism that minimizes employee contact with roasted beans during

blending.

5. Continue to cover bins of roasted beans to aid in reducing the overall emission of

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

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

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

the roasted bean bins.

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

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

efficiency, energy usage, and roaster performance.

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

CO, CO2, dust) in the workplace and how to protect themselves. OSHA’s Hazard

Communication Standard, also known as the “Right to Know Law” [29 CFR

1910.1200] requires that employees are informed and trained on potential work

hazards and associated safe practices, procedures, and protective measures.
Page 34 Health Hazard Evaluation Report 2016-0013-3294

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

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

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

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

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

should share this report with their healthcare providers.

Personal Protective Equipment

Personal protective equipment in the form of respiratory protection is considered the least 

effective means for controlling hazardous respiratory exposures because breakdowns in 

implementation can result in insufficient protection. Proper use of respiratory protection 

(respirators) requires a comprehensive respiratory protection program and a high level of 

employee and management involvement and commitment to assure that the right type of 

respirator is chosen for each hazard, respirators fit users and are maintained in good working 

order, and respirators are worn when they are needed. Supporting programs such as training, 

change-out schedules, and medical assessment may be necessary. Respirators should not be 

the sole method for controlling hazardous inhalation exposures. Rather, respirators should be 

used until effective engineering and administrative controls are in place.

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

potential option to further reduce exposures to alpha-diketones (e.g., diacetyl and

2,3-pentanedione). If follow-up air sampling after engineering controls have been

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

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

tasks with elevated exposures. If respiratory protection is used, NIOSH-certified

respirators should be fitted with organic vapor cartridges and particulate filters. The

choice of respirator should be guided by personal exposure sampling for diacetyl and

2,3-pentanedione (NIOSH 2004). Respirators have assigned protection factors (APFs).

APF refers to the highest level of protection a properly selected respirator can provide.

For instance, air-purifying half-face respirators have an assigned protection factor

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

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

APFs can be found in Table 1 of OSHA Respiratory Protection Standard at https://

www.osha.gov/pls/oshaweb/owadisp.show_document?p_table=STANDARDS&p_

id=12716.

 If mandatory respiratory protection is used, a written respiratory protection program 

should be implemented as required by the OSHA Respiratory Protection Standard (29 

CFR 1910.134), including training, fit testing, maintenance and use requirements. 

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

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

as when emptying burlap bags of green beans into the storage silos, cleaning the
Health Hazard Evaluation Report 2016-0013-3294 Page 35

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

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

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

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

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

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

respiratory_protection/voluntaryuse_transcript.html.

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

2,3-pentanedione, or 2,3-hexanedione). In cases of dual exposure to dust and alphadiketones, NIOSH-certified organic vapor cartridges (for the alpha-diketones) and 

particulate cartridges/filters (for the dust) would be warranted.

Medical Monitoring

The purpose of a medical monitoring program is to help assure the health of employees 

who have workplace exposures (e.g., diacetyl, 2,3-pentanedione, green coffee beans/dust) 

known to pose risk for potentially serious health conditions such as asthma or obliterative 

bronchiolitis. 

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

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

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

that employees in the production area that roasted coffee, ground coffee, blended coffee by 

hand, or weighed and packaged roasted coffee could be exposed to diacetyl above the NIOSH 

REL or STEL. 

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

area. The medical monitoring should consist of evaluation with a questionnaire (to obtain 

health and work task information) and spirometry (to assess lung function) at baseline and 

at one year to monitor for respiratory symptoms and to establish employees’ baseline in 

lung function and any abnormal decline in lung function in the first year. Subsequently, an 

annual questionnaire evaluation should occur to monitor for respiratory symptoms. New or 

worsening respiratory symptoms should prompt additional evaluation including spirometry. 

Details about spirometry and a medical monitoring program can be found in chapter 9 of the 

NIOSH Criteria Document [NIOSH 2016].

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]. 
Page 36 Health Hazard Evaluation Report 2016-0013-3294

Smoking Cessation Program

In a workplace with risk of occupational lung disease, prevention of smoking-related lung 

disease is important and makes the detection of work-related adverse effects easier. We 

recommend implementing a smoking cessation program to assist employees to stop smoking. 

The Centers for Disease Control and Prevention offers tools and resources for setting up a 

smoking cessation program [CDC 2017b]. 
Health Hazard Evaluation Report 2016-0013-3294 Page 37

Table A1. Time-weighted average OSHA Method 1013/1016 personal and area air sampling 

results by location, NIOSH survey, April 2016

Analyte Sample 

Type

Job Description, 

Location N

Above 

LOD

N (%)

Minimum

Concentration

(ppb)

Maximum

Concentration

(ppb)

Above 

REL

N 

Diacetyl Personal Production Manager,

Office and Production 2 2 (100%) 0.9 1.2 0

Diacetyl Personal Administrative,

Office Area 7 5 (71%) <0.3 2.1 0

Diacetyl Personal Production,

Production Area 12 12 (100%) 1.6 13.1 11

Diacetyl Personal Roaster Operator,

Roasting 6 6 (100%) 4.3 10.9 5

Diacetyl Area Grinding 3 3 (100%) 16.8 51.1 N/A

Diacetyl Area Office Area 6 1 (17%) <0.3 0.4 N/A

Diacetyl Area Packaging 6 6 (100%) 5.9 17.6 N/A

Diacetyl Area Production Area 9 9 (100%) 2.8 11.0 N/A

Diacetyl Area Quality Control 3 3 (100%) 0.3 0.8 N/A

Diacetyl Area Roasting 8 8 (100%) 3.8 11.6 N/A

2,3-Pentanedione Personal Production Manager,

Office and Production 2 2 (100%) 0.5 1.0 0

2,3-Pentanedione Personal Administrative,

Office Area 7 4 (57%) <0.3 0.9 0

2,3-Pentanedione Personal Production,

Production Area 12 12 (100%) 1.8 7.5 0

2,3-Pentanedione Personal Roaster Operator,

Roasting 6 6 (100%) 2.6 6.0 0

2,3-Pentanedione Area Grinding 3 3 (100%) 9.7 26.7 N/A

2,3-Pentanedione Area Office Area 6 2 (33%) <0.3 0.4 N/A

2,3-Pentanedione Area Packaging 6 6 (100%) 3.2 11.6 N/A

2,3-Pentanedione Area Production Area 9 9 (100%) 1.9 5.7 N/A

Appendix A: Tables
Page 38 Health Hazard Evaluation Report 2016-0013-3294

Analyte Sample 

Type

Job Description, 

Location N

Above 

LOD

N (%)

Minimum

Concentration

(ppb)

Maximum

Concentration

(ppb)

Above 

REL

N 

2,3-Pentanedione Area Quality Control 3 3 (100%) 0.5 1.0 N/A

2,3-Pentanedione Area Roasting 8 8 (100%) 2.0 6.6 N/A

2,3-Hexanedione Personal Production Manager,

Office and Production 2 0 (0%) <0.2 <0.3 -

2,3-Hexanedione Personal Administrative,

Office Area 7 0 (0%) <0.2 <0.2 -

2,3-Hexanedione Personal Production,

Production Area 12 4 (33%) <0.2 0.4 -

2,3-Hexanedione Personal Roaster Operator,

Roasting 6 2 (33%) <0.2 0.4 -

2,3-Hexanedione Area Grinding 3 3 (100%) 0.3 1.3 N/A

2,3-Hexanedione Area Office Area 6 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Packaging 6 2 (33%) <0.2 0.6 N/A

2,3-Hexanedione Area Production Area 9 1 (11%) <0.2 0.3 N/A

2,3-Hexanedione Area Quality Control 3 0 (0%) <0.2 <0.2 N/A

2,3-Hexanedione Area Roasting 8 1 (13%) <0.2 0.4 N/A

Note: OSHA=Occupational Safety and Health Administration; N=number of samples; Above LOD N (%)=number 

and percentage of samples above limit of detection (LOD); < indicates below the LOD; ≤ indicates less than or 

equal to the LOD; % Above REL=percentage of samples above the NIOSH recommended exposure limit (REL); 

ppb=parts per billion; N/A indicates that NIOSH RELs are specified for personal air samples and area air 

samples cannot be used for direct comparisons with area samples; “Production Area” location includes employees 

that were cross-trained and performed tasks at different areas; “−“indicates that there is currently no REL for 

2,3-hexanedione. 

Table A1 (cont). Time-weighted average OSHA Method 1013/1016 personal and area air 

sampling results by location, NIOSH survey, April 2016
Health Hazard Evaluation Report 2016-0013-3294 Page 39

Table A2. Summary of OSHA Method 1013/1016 personal air sampling results by task, NIOSH 

survey, April 2016

Analyte Task N

Above LOD

N (%)

Minimum 

Concentration 

(ppb)

Maximum 

Concentration 

(ppb)

Mean (range) 

Sample Duration 

(minutes)

Diacetyl Cleaning Roaster 1 1 (100%) 14.4 14.4 ̶

Diacetyl Grind coffee beans 9 9 (100%) 27.4 375.4 12 (3-15)

Diacetyl Package coffee 10 9 (90%) <=1.1 29.7 17 (6-53)

Diacetyl Roast coffee beans 38 32 (84%) <0.7 13.2 20 (0-86)

2,3-Pentanedione Cleaning Roaster 1 1 (100%) 9.2 9.2 ̶

2,3-Pentanedione Grind coffee beans 9 9 (100%) 15.0 219.2 12 (3-15)

2,3-Pentanedione Package coffee 10 8 (80%) <0.8 20.9 17 (6-53)

2,3-Pentanedione Roast coffee beans 38 29 (76%) <0.6 6.2 20 (0-86)

2,3-Hexanedione Cleaning Roaster 1 0 (0%) <1.2 <1.2 ̶

2,3-Hexanedione Grind coffee beans 9 3 (33%) <0.7 1.5 12 (3-15)

2,3-Hexanedione Package coffee 10 1 (10%) <0.7 0.8 17 (6-53)

2,3-Hexanedione Roast coffee beans 38 0 (0%) <0.1 . 20 (0-86)

Note: OSHA=Occupational Safety and Health Administration; N=number of samples; Above LOD N (%)=number and 

percentage of samples above limit of detection (LOD); < indicates below the LOD; ≤ indicates less than or equal to the 

LOD; “All Over” includes employees that were cross-trained and performed tasks at different areas.

Table A3. Instantaneous evacuated canister method* air sampling results by task, NIOSH survey, 

April 2016

Task Description Diacetyl 

(ppb)

2,3-Pentanedione 

(ppb)

2,3-Hexanedione 

(ppb)

Dumped French Roast beans from storage bin into hopper 24.4 9.4 1.7

Grinding 5 pound bags 28.3 10.9 <0.9

Grinding coffee 19.0 10.3 <0.9

Hand blending roasted beans 10.7 6.0 <0.9

Hand blending roasted beans 25.2 11.5 <1.1

Hand blending roasted beans 10.2 5.6 <0.9

Hand blending roasted beans 6.6 3.4 <0.9

Pouring roasted beans into Weigh/Pack hopper 6.3 3.3 <1.5

Dumping roasted beans into cooling bin 8.3 5.1 <1.3

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.
Page 40 Health Hazard Evaluation Report 2016-0013-3294 Table A4. Instantaneous evacuated canister method* air sampling results by source, NIOSH survey, April 2016 Source Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) At fan at the back of the 5 pound grinder 124 35.0 2.8 At fan at the back of the 5 pound grinder 225 87.4 6.9 Beside velocicalc while worker ground 5 pound bags 150 69.2 5.0 Beside velocicalc while worker ground 5 pound bags 253 120 8.6 Checking smell and color of roasting beans; Sumatran Light Roast 23.4 11.9 <1.3 Cleaning chaff out of exhaust line from Diedrich Roaster 32.0 20.8 1.7 Cleaning chaff out of exhaust line from Diedrich Roaster 18.9 7.2 <0.9 Cleaning chaff out of exhaust line from Diedrich Roaster 22.2 13.2 1.0 Degassing a bag of Organic French Roast 4322 1389 54.1 Dumped roasted beans from roaster into cooling bin 5.6 3.6 <1.2 Dumped roasted beans from plastic storage bin into hopper 0.3 <0.4 <0.6 Dumped roasted beans from roaster cooling bin into plastic bin 5.5 2.8 <0.9 Dumped roasted beans from roaster cooling bin into plastic bin 0.6 0.6 <0.6 Dumped roasted beans from Primo roaster cooling bin into plastic bin 2.3 0.9 <1.0 Dumped Decaf Peru beans from cooling bin into storage bin 2.2 1.2 <0.9 Dumped Ecuador beans from cooling bin into storage bin 1.7 0.7 <0.9 Dumped Ecuador beans from cooling bin into storage bin 5.5 3.8 1.6 Dumped roasted beans from roaster cooling bin into plastic bin 9.0 1.3 <0.9 Dumped roasted beans from roaster cooling bin into plastic bin 11.2 5.5 <1.0 Dumped roasted beans from roaster cooling bin into plastic bin 3.7 2.1 <1.0 Filling 12 ounce bag with ground coffee 147 113 5.8 Grinding 5 pound bag of coffee beans 20574 9910 525
Health Hazard Evaluation Report 2016-0013-3294 Page 41 Source Description Diacetyl (ppb) 2,3-Pentanedione (ppb) 2,3-Hexanedione (ppb) Dumping decaffeinated roasted beans from cooling bin into storage bin 26.5 15.3 1.1 Dumping French Roast roasted beans from cooling bin into storage bin 5.4 3.0 1.2 Dumping roasted beans from cooling bin into storage bin 58.4 28.6 2.2 Pulling decaffeinated roasted beans from cooling bin through destoner and into storage bin 60.9 28.8 1.6 Pulling French Roast roasted beans from cooling bin through destoner and into storage bin 2.1 1.0 <0.9 Pulling French Roast roasted beans from cooling bin through destoner and into storage bin 109 41.4 4.5 Pulling roasted beans from cooling bin through destoner and into storage bin 37.0 21.8 1.4 Dumping roasted beans from cooling bin into storage bin 12.8 6.5 1.2 Roaster checking the smell and color of beans 10.1 6.3 1.6 Roaster checking the smell and color of beans 7.9 4.8 <2.2 Table A4 (cont.). Instantaneous evacuated canister method 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. * air sampling results by source, NIOSH survey, April 2016
Page 42 Health Hazard Evaluation Report 2016-0013-3294 April 2016 oasted coffee beans, NIOSH survey, bulk samples of r esults* for able A5. Headspace analysis r T ences in headspace analysis results. some of the differ esponsible for different amounts of time, and this could be r *The roasted coffee beans off-gassed for billion Note: ppb=parts per Diacetyl 2,3-Pentanedione 2,3-Hexanedione Sample Type Bulk Sample Description (ppb) (ppb) (ppb) Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans Coffee beans French Roast, Diedrich Roaster French Roast, Diedrich Roaster Decaf Full City, Diedrich Roaster Wonderland Park Espresso, Primo Roaster Med/Dark Pangda, Primo Roaster Bolivian, Primo Roaster Sol y Café, Primo Roaster Full City, Primo Roaster Peruvian Natural, Primo Roaster Honduran Honey, Primo Roaster Polinator, Primo Roaster Mexican Dark, Primo Roaster Nicaragua, Primo Roaster Espresso, Primo Roaster Decaf Dark, Diedrich Roaster 9216 6225 275 2295 2043 0 7286 6853 278 2557 3063 0 2898 3164 0 2806 3578 0 1651 2474 0 3077 4242 0 1656 2478 0 205 192 0 971 1128 0 472 234 0 311 191 0 1386 756 0 5183 3020 0
Health Hazard Evaluation Report 2016-0013-3294 Page 43 Experienced in the last 12 months Experienced in the last 4 weeks Symptom N = 13 N = 13 Number (%) Number (%) Nose symptoms* 11 (85%) 7 (54%) Eye symptoms† 10 (77%) 6 (46%) Sinusitis or sinus problems 6 (46%) 2 (15%) Problem with ability to smell 6 (46%) - Phlegm on most days for 3 months 2 (15%) - Lower respiratory symptoms (reported at least one of the following) 8 (62%) 5 (38%) Breathing trouble 5 (38%) 3 (23%) Chest wheezing or whistling 4 (31%) 3 (23%) Awoke with chest tightness 4 (31%) 1 (8%) SOB on level ground or walking up a slight a hill 2 (15%) - Awoke with shortness of breath 2 (15%) 1 (8%) Asthma attack 1 (8%) 0 Usual cough 0 0 Systemic symptoms(reported at least one of the following) 11 (85%) 3 (23%) Flu-like achiness or achy joints 8 (62%) 0 Fever or chills 6 (46%) 1 (8%) Unusual tiredness or fatigue 3 (23%) 3 (23%) the symptom. four week question was not asked for eath; “-“= A of participants; SOB=shortness of br Note: N=number 2) stinging, burning nose. , or runny nose or 2) stinging, burning eyes. both of the following: 1) stuffy, itchy , itchy eyes or both of the following: 1) watery *Nose symptoms includes one or †Eye symptoms includes one or . Prevalence of reported symptoms, NIOSH medical survey, June 2016 6 A able T
Page 44 Health Hazard Evaluation Report 2016-0013-3294

Table A7. Adjusted* comparisons of symptoms and self-reported physician diagnosis 

among NIOSH medical survey participants (N=12) to U.S. adult population, June 2016

Health condition Comparative population† Observed 

Number

Expected 

Number

SMR

(95% CI)‡

Watery, itchy eyes last 12 months NHANES III 9 5.2 1.7 (0.9-3.3)

Stuffy, itchy, or runny nose last 12 months NHANES III 11 7.2 1.5 (0.8-2.7)

Sinus problems last 12 months NHANES III 6 4.6 1.3 (0.6-2.8)

Phlegm 3 consecutive month or more NHANES III 2 0.7 2.8 (0.8-10.3)

Wheeze last 12 months NHANES 2007-2012 3 1.5 2.0 (0.7-5.8)

Shortness of breath on exertion NHANES III 2 1.9 1.1 (0.3-3.9)

Chronic bronchitis (physician-diagnosed) NHANES III 1 0.5 1.9 (0.3-10.9)

Ever asthma (physician-diagnosed) NHANES 2007-2012 4 1.8 2.2 (0.9-5.9)

Current asthma (physician-diagnosed) NHANES 2007-2012 2 0.8 2.4 (0.7-8.8)

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.
Health Hazard Evaluation Report 2016-0013-3294 Page 45

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

2,3-hexanedione, coffee, volatile organic compounds (VOCs).
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Health Hazard Evaluation Report 2016-0013-3294 Page 55

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).

Disclaimers 

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 

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Acknowledgments

Desktop Publisher: Tia McClelland 

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

NIOSH Laboratory Assistance: Dru Burns, Kyle Hatcher, Ryan LeBouf, Anand Ranpara

Site Visit Team Members: Rachel Bailey, Matthew Duling, Brie Hawley, Robert Lawrence, 

Stephen Martin, Jr., and Brian Tift

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facility. The state and local 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 http://www.cdc.gov/niosh/hhe/reports/pdfs/2016-0013-3294.pdf.

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

Recommended citation for this report:

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

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

S, Duling M, Bailey RL. 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. 2016-0013-3294.
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