Health Hazard Evaluation Report 2015-0082-3287 Page 1 

Evaluation of exposures and respiratory
 

health at a coffee roasting and packaging
 

facility 

Report No. 2015-0082-3287 

August 2017 

Ryan F. LeBouf, PhD, CIH 

Stephen B. Martin, Jr., PhD, PE 

Christopher Mugford, MS 

Marcia L. Stanton, BS 

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 

Contents 

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

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

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

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

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

Process Description ............................. 5 

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

Results ................................................ 15 

Discussion .......................................... 22 

Conclusions ........................................ 28 

Recommendations............................. 29 

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

Appendix A: Tables ............................ 41 

Appendix B: Figures .......................... 54 

Acknowledgements........................... 58 

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

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

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

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

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

not be related to this Health Hazard Evaluation. 

Health Hazard Evaluation Report 2015-0082-3287 
Page i 

Highlights of this Evaluation 

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

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

regarding concerns about exposures to and health effects from diacetyl and 2,3-pentanedione 

during coffee roasting and grinding. 

What We Did 

●	 We visited the coffee roasting and 

packaging facility on July 14-16, 2015 

and March 9-11, 2016. 

●	 We collected full-shift (hours), task 

(minutes), and instantaneous (seconds) 

air samples to measure concentrations 

of the alpha-diketones diacetyl, 

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

over multiple days during each visit.
	

●	 We collected roasted coffee beans 

(whole bean and ground) 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 collected air samples for dust 

throughout the facility. 

● We assessed the ventilation system at the 

facility. 

●	 We administered a health questionnaire 

to employees and performed breathing 

tests. 

What We Found 

●	 On full-shift sampling, some employees 

(roaster operator, grinder operator, 

and weigh/package employees) were 

exposed to diacetyl at concentrations 

above the recommended exposure limit 

for diacetyl of 5 parts per billion, with 

the highest measured concentration of 

8.4 parts per billion. 

We evaluated respiratory health and 

airborne exposures to alpha-diketones 

(diacetyl, 2,3-pentanedione, and 

2,3-hexanedione), other volatile organic 

compounds, carbon monoxide, and 

carbon dioxide during coffee roasting, 

grinding, and packaging. Diacetyl and 

2,3-pentanedione were detected in a 

majority of full-shift personal breathing 

zone air samples, with a maximum 

concentration of diacetyl of 8.4 parts per 

billion and of 2,3-pentanedione of 5.7 parts 

per billion. Ten of the full-shift samples 

exceeded the NIOSH recommended 

exposure limit for diacetyl of 5 parts per 

billion. In addition, air sampling during 

short-term tasks identified several tasks 

(e.g., grinding roasted coffee beans and 

blending roasted coffee beans) with higher 

exposures to alpha-diketones, including 

diacetyl, than other tasks. Exposures were 

higher when bay doors were closed and 

increased over the course of the work 

shift. Eye, nose, and sinus symptoms were 

the most commonly reported symptoms. 

Wheezing was the most common lower 

respiratory symptom reported; four times 

as many employees as expected reported 

this symptom than in the U.S. population 

with a similar demographic distribution. 

One participant had abnormal spirometry 

not thought to represent flavoring-related 

lung disease. We recommend operating 

the exhaust fan and make-up air system in 

the production space whenever occupied; 

installing local exhaust ventilation; 

implementing administrative controls 

such as modification of work practices; 

and training employees about work-place 

hazards. We also recommend instituting a 

medical monitoring program. 

Health Hazard Evaluation Report 2015-0082-3287 
Page ii 

●	 During the second visit, higher alpha-diketone exposures were measured likely due to 

decreased natural ventilation and higher production volumes. Bay doors were open in 

July 2015 and closed in March 2016 due to colder temperatures. 

●	 Levels of diacetyl in the air during short-term sampling were higher for tasks involving 

grinding roasted beans (maximum 37.6 parts per billion), blending roasted beans by 

hand (maximum 33.4 parts per billion), and weighing and packaging roasted coffee 

(maximum 34.3 parts per billion). 

●	 Carbon dioxide and carbon monoxide levels were higher inside roasted bean storage 

bins but generally low throughout the facility. 

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

2,3-hexanedione.
	

●	 All area air samples for dust were below occupational exposure limits. 

●	 During the first visit, the roof-top exhaust stack for one of the roasters had an 

accumulation of chaff that could negatively affect ventilation efficiency, energy usage, 

and roaster performance. During the second visit, both exhaust stacks had been cleaned 

and were clear of debris. 

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

employees reported their symptoms were caused or aggravated by green coffee dust, 

chaff, roasted coffee, ground coffee dust, or odors from the heat sealing machine. 

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

symptom; four times as many employees reported wheezing than expected. 

●	 One of 16 participants had abnormal spirometry that significantly improved after 

bronchodilator treatment and was not thought to represent flavoring-related lung 

disease or asthma. 

●	 One of 16 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. 

●	 Ensure the continuous operation of the exhaust fan and the make-up air system in the 

production space at all times during production activities. 

●	 Weather permitting, open the bay doors and outside windows during roasting, grinding, 

and packaging of roasted coffee beans. 

●	 Follow manufacturer’s guidelines for periodic cleaning of the roasters’ exhausts. 

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

●	 Minimize production tasks that require employees to place their heads inside roasted 

Health Hazard Evaluation Report 2015-0082-3287 
Health Hazard Evaluation Report 2015-0082-3287 Page iii 

bean bins. 

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

●	 Consider installing local exhaust ventilation to reduce air concentrations of alphadiketones during the following tasks: 1) blending roasted coffee by hand, if an 

alternative method cannot be provided; 2) grinding roasted coffee, and 3) weighing and 

packaging roasted coffee. 

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

reducing exposures to below the recommended exposure limits. 

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

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

possible. 

●	 Make N95 disposable filtering-face piece respirators available for voluntary use for 

protection against dust exposure when emptying burlap bags of green beans into 

the storage silos, cleaning the roaster exhaust system of chaff, emptying the chaff 

containers, or cleaning the green bean storage area. 

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

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

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

What Employees Can Do 

●	 Operate the exhaust fan at all times during production activities. 

●	 Weather permitting, open the bay doors and outside windows during roasting, grinding, 

and packaging of roasted coffee beans. 

●	 As much as possible, avoid placing your head directly inside roasted bean storage bins. 

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

coffee beans. 

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

●	 Although dust exposures were below exposure limits, some employees may wish to 

use N95 disposable filtering-facepiece respirators when emptying burlap bags of green 

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

chaff containers, or cleaning the green bean storage area. 

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

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

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

employer.
	
Page iv Health Hazard Evaluation Report 2015-0082-3287

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Page v 

Abbreviations
 

μm 

μg 

°F 

ACGIH® 

APF 

AX 

cfm 

CFR 

CO 

CO2 

COPD 

DR5-R20 

FEV1 

fpm 

Fres 

FVC 

HVAC 

Hz 

kPa/(L/s) 

IDLH 

IOM 

LPM 

LOD 

LOQ 

mg/m3 

mL 

mL/min 

NHANES 

NIOSH 

OEL 

OSHA 

PEL 

ppb 

ppm 

R5 

Micrometer 

Microgram 

degrees Fahrenheit 

American Conference of Governmental Industrial Hygienists 

Assigned protection factor 

Area of reactance 

Cubic feet per minute 

Code of Federal Regulations 

Carbon monoxide 

Carbon dioxide 

Chronic obstructive pulmonary disease 

The difference between resistance at 5 and 20 Hertz 

1-second forced expiratory volume 

Feet per minute 

Resonant frequency 

Forced vital capacity 

Heating, ventilation, and air-conditioning 

Hertz 

Kilopascals per liter per second 

Immediately dangerous to life or health 

Institute of Occupational Medicine 

Liters per minute 

Limit of detection 

Limit of quantitation 

Milligrams per cubic meter of air 

Milliliter 

Milliliter per minute 

National Health and Nutrition Examination Survey 

National Institute for Occupational Safety and Health 

Occupational exposure limit 

Occupational Safety and Health Administration 

Permissible exposure limit 

Parts per billion 

Parts per million 

Resistance at 5 Hertz 

Health Hazard Evaluation Report 2015-0082-3287 
Page vi Health Hazard Evaluation Report 2015-0082-3287

R20 Resistance at 20 Hertz 

REL Recommended exposure limit 

RH Relative humidity 

SMR Standardized morbidity ratio 

STEL Short-term exposure limit 

TLV® Threshold limit value 

TVOC Total volatile organic compound 

TWA Time-weighted average 

US United States 

VOC Volatile organic compound 

X5 Reactance at 5 Hertz 
Health Hazard Evaluation Report 2015-0082-3287 Page 1 

Summary 

In April 2014, the National Institute for Occupational Safety and Health’s Health Hazard 

Evaluation Program received a request from the management of a coffee roasting and 

packaging facility with 26 employees regarding concerns about exposures to and health 

effects from diacetyl and 2,3-pentanedione during coffee roasting and grinding. In July 

2015, we conducted the initial industrial hygiene survey and ventilation assessment at the 

facility. The industrial hygiene survey consisted of collecting personal breathing zone and 

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

and dust. Bulk samples of whole bean and ground roasted coffee were collected to evaluate 

the potential for emission of diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We used 

continuous monitoring instruments to measure total volatile organic compounds, carbon 

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

tasks. We also conducted a ventilation assessment in the production and office areas and 

held brief individual interviews with employees. Two interim reports with recommendations 

were sent to the company following our first visit. In March 2016, we conducted a second 

industrial hygiene survey, a second ventilation assessment, and a medical evaluation of 

employees. The industrial hygiene survey included the collection of air and bulk samples 

for diacetyl, 2,3-pentanedione, and 2,3-hexanedione. We used continuous monitoring 

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

dioxide in specific areas and during specific work tasks. The medical survey consisted of a 

health questionnaire and breathing tests. 

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

consistently higher during our second industrial hygiene survey in March 2016. During our 

second visit, the production area exhaust fan was off, the bay doors were closed, and more 

coffee was processed, which likely contributed to the higher concentrations. Ten of the 49 

full-shift samples collected during the two surveys exceeded the NIOSH recommended 

exposure limit for diacetyl of 5 parts per billion, with a maximum concentration of 8.4 

parts per billion. We identified jobs where some work tasks resulted in relatively higher 

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

blending roasted coffee beans by hand, and weighing and packaging roasted coffee were 

associated with higher diacetyl levels. Overall, the most commonly reported symptoms 

were associated with mucous membranes, specifically the eyes, nose, and sinuses. Some 

production employees reported their mucous membrane symptoms were caused or 

aggravated by green coffee dust or chaff, roasted coffee, or ground coffee dust. Wheezing 

or whistling in the chest was the most commonly reported lower respiratory symptom, 

and was four times higher than that expected when compared to the U.S. population of 

the same age, race/ethnicity, sex, and cigarette smoking distribution. One participant 

had abnormal spirometry not thought to represent flavoring-related lung disease and one 

participant had high exhaled nitric oxide, a marker of allergic airways inflammation. We 

recommend operating the exhaust fan and make-up air system in the production space during 

occupancy, 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 2015-0082-3287

Introduction 

In April 2015, the National Institute for Occupational Safety and Health (NIOSH) received 

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

facility regarding potential worker exposure to diacetyl and 2,3-pentanedione during coffee 

processing. In July 2015, we conducted an initial ventilation assessment and industrial 

hygiene survey at the facility while the bay doors on both ends of the coffee processing 

area were open, increasing natural ventilation. We collected area and personal breathing 

zone air samples for dust and volatile organic compounds (VOCs), including diacetyl, 

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

dioxide (CO2

), and total VOCs. After the first visit, we provided two interim reports with 

recommendations. In March 2016, we conducted a second ventilation assessment and 

industrial hygiene survey while the bay doors were closed; we also 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 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 
Health Hazard Evaluation Report 2015-0082-3287 Page 3 

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

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

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

] 

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

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

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 no established 

occupational exposure limits for 2,3-hexanedione. 

Carbon Monoxide and Carbon Dioxide 

CO and CO2

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

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

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

Inhalable and Respirable Dust 

Dust refers to the particles present in air, either from natural forces or from mechanical 

processes. Inhalable and respirable dust particles differ by their size. Inhalable dust particles 

are larger and can enter the nose and mouth during breathing and can deposit in the upper and 

lower respiratory tract. Respirable dust particles are very small and can reach the deepest (gas 

exchange) parts of the lungs. Occupational exposure limits for inhalable and respirable dust 

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]. It has 

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

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

facility found diacetyl and 2,3-pentanedione concentrations in the air that were 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 
Page 4 Health Hazard Evaluation Report 2015-0082-3287

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

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

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

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

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

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

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

workers at coffee roasting and packaging facilities that produce only unflavored coffee. 

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]. 

Previous Industrial Hygiene Sampling at This Coffee Roasting and Packaging Facility 

On March 3, 2015, an industrial hygienist, hired by a local newspaper, collected personal 

air samples using OSHA Method 1012 on three employees during roasting (two roaster 

operators) and grinding (one grinder operator) at the facility that is the subject of this 

report. The bay doors in the production area were closed during sampling. According to the 

industrial hygiene report dated March 15, 2015, measureable levels of diacetyl were detected 

in all three personal air samples. Measureable levels of 2,3-pentanedione (using OSHA 

method 1016) were detected from the two roaster operators but not the grinder operator. TWA 

personal exposures to diacetyl for the two roaster operators and the grinder operator were 6.9 

ppb (roaster operator #1), 8.1 ppb (roaster operator #2), and 19.3 ppb (grinder operator) and 

exceeded the NIOSH REL for diacetyl in all samples. The TWA personal air concentrations 

for 2,3-pentanedione were 5.3 ppb (roaster operator #1), 5.6 ppb (roaster operator #2), and 

6.4 ppb (grinder operator) and did not exceed the NIOSH REL for 2,3-pentanedione. 

Based on these air sampling results, the coffee roasting and packaging company wanted to be 

proactive and more fully characterize concentrations of alpha-diketones in the air and assess 

the efficiency of the existing ventilation systems. In April 2015, the management submitted a 

health hazard evaluation request to NIOSH. 
Health Hazard Evaluation Report 2015-0082-3287 Page 5 

Process Description 

In April 2013, the company moved from another facility to the location that was evaluated. 

Their evaluated facility was approximately 16,000 square feet with 11,000 square feet 

dedicated to production activities and 5,000 square feet for office space. The company had 

approximately 26 onsite employees at the time of the first survey and 25 at the time of the 

second survey. The employees were not represented by a union. Production was divided into 

two shifts with seven production employees from 8 am to 4 pm and three employees from 

1 pm to 9 pm. About half of the employees were involved in various administrative tasks 

including accounts receivable, customer service, inventory control, graphic design, sales, and 

farmer relations. The remaining employees worked in the production area (described below). 

There was no café onsite. The following describes activities at the time of the NIOSH visits 

in July 2015 and March 2016. Roasted coffee production was greater during the second visit. 

Green beans were received in burlap bags from countries around the world including, but not 

limited to, Colombia, Guatemala, Mexico, and Honduras. Upon arrival at the facility, pallets 

of green beans in burlap bags were stored on shelves in the green bean receiving department 

until they were dispensed into large green bean storage silos, located next to the roasters. 

At the time of our first visit, roaster operators climbed an A-frame ladder to empty burlap 

bags of green beans into the green bean storage silos. At our second visit, a permanent stair 

structure had replaced the A-frame ladder to the green bean storage silos, following NIOSH 

recommendations made as a result of our first visit. To prepare a batch for roasting, a roaster 

operator opened a small door at the bottom of the green bean storage silo and dispensed 

green beans into a container, on a scale, to achieve the proper weight needed for a roast. The 

green beans were manually emptied into the hopper of either one of two roasters (convection 

or conduction roasters). The green beans were automatically conveyed from the hopper into 

the roasting drum where they were heated at a specific temperature and time period for the 

desired roast. At the end of each roast cycle, a roaster operator opened a slot at the bottom of 

the roaster that emptied the roasted beans into a cooling drum where they were automatically 

mixed by an agitator to accelerate cooling. 

The cooling drum utilized a downdraft exhaust system that drew air over the roasted beans 

and down into the cooling drum to accelerate cooling. The downdraft system exhausted out 

through the roof. A roaster operator monitored the roasting equipment carefully throughout 

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

cooling drum into plastic containers. A roaster operator then manually moved the containers 

to an elevator lift that raised one or more buckets of roasted coffee beans to an elevated 

platform. At the time of our first visit, there was an unguarded section of the platform by 

the hydraulic lift which increased the risk for unintentional fall injuries. At our second 

visit, a guard had been added to the platform by the hydraulic lift, following NIOSH 

recommendations from our first visit. On the platform, the roaster operator emptied the 

buckets of roasted coffee beans into their respective storage bins on the other side of the 

platform. 

An employee in the weigh and pack area dispensed the roasted beans from small doors at 
Page 6 Health Hazard Evaluation Report 2015-0082-3287

the bottom of the roasted bean storage bins into a plastic container to obtain the desired 

amount for grinding or packaging. For orders requiring mixtures of different roasted coffee 

beans, blends were completed by either automatically mixing batches in the cooling drum 

or manually mixing batches in storage containers. For whole bean coffee, the roasted beans 

were manually transferred using buckets into an automatic weigh-fill packaging machine 

where mainly three different amounts were dispensed for packaging: 12 ounces, 2 pounds, 

and 5 pounds. The company also packaged smaller, fraction packs in 2.5-ounce, 3-ounce, and 

8-ounce bags. For ground coffee, individual, pre-weighed packages of roasted whole beans 

were manually emptied into a grinder. The packages were placed at the bottom of the grinder 

to collect the ground coffee during grinding. There were three grinding machines, one of 

which was only used for grinding espresso beans. The grinders could be adjusted for type of 

grind (coarse, medium, or fine). 

One or more employees (often grinder operators) heat-sealed packages of whole bean and 

ground coffee and placed the bags on storage shelves in the storage and holding area or 

immediately packed them for shipment or local delivery. All packages were equipped with 

one-way valves for off-gassing. 

Quality Control 

The company took measures to ensure the quality of green and roasted beans. The facility 

had a quality control room located between the production and office areas where roasted 

beans and brews could be prepared and assessed. Upon receipt, an employee profiled the 

green beans to determine the best roast temperature and time. Green beans stored in silos 

were monitored over time as they aged and roasting specifications were adjusted to account 

for any changes in the green beans. Within each specific type of roast, the roasted beans were 

packaged in the order they were roasted to ensure freshness. 

Cleaning Activities 

Various cleaning techniques were used throughout the production areas. Employees used 

brooms to sweep the production floor, wet or dry wipes on table tops and equipment surfaces, 

and compressed air to remove coffee bean dust from surfaces and equipment. The facility had 

a wash station equipped with a commercial dishwasher that washed buckets and containers 

for reuse. 

Repair Activities 

One employee repaired production equipment and customers’ coffee roasting equipment 

(roasters, grinders, and espresso machines). 

Personal Protective Equipment 

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

observe employees wearing respiratory protection for chemicals or dust during either of our 

visits. Hearing protection was available for voluntary use at each roaster. 
Health Hazard Evaluation Report 2015-0082-3287 Page 7 

Methods 

We initially visited the coffee roasting and packaging facility in July 2015. We held an 

opening meeting with management and employees, collected bulk samples and air samples, 

performed a ventilation assessment, and had informal interviews with employees. The bay 

doors in the production area were open during this visit. At the conclusion of our site visit, 

we held a closing meeting with management and employees. Two interim reports with 

recommendations were sent to the company following our first visit. We visited the facility 

again in March 2016. We collected bulk samples and air samples and performed another 

ventilation assessment with the bay doors closed; we also conducted a medical survey. 

We had the following objectives for the health hazard evaluation: 

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

during coffee processing; 

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

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

3. Measure levels of CO, CO2

, and inhalable and respirable dust throughout the facility; 

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

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

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

6. Determine if employees had abnormal lung function tests; 

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

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

Industrial Hygiene Survey 

Sampling Times for Alpha-Diketones 

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

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

Sampling was conducted over multiple days during each site visit. 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 Administration 

(OSHA) Methods 1013/1016 

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

2,3-hexanedione on silica gel sorbent tubes during both industrial hygiene surveys over 
Page 8 Health Hazard Evaluation Report 2015-0082-3287

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

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

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

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

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

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

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

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

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

results reflected a full work shift (8-hour) TWA exposure. Although this 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” 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 from both visits were analyzed using 

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

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

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

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

background and is a 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 decreased between 

the first and second visit. The LODs for the first visit were 0.049 micrograms per sample 

(μg/sample) for diacetyl, 0.046 μg/sample for 2,3-pentanedione, and 0.053 μg/sample for 

2,3-hexanedione; these were based on the lowest mass used in the calibration curve. These 

equate to 1.5 ppb for diacetyl, 1.6 ppb for 2,3-pentanedione, and 1.3 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 LOQs for the first visit equate to 5.0 ppb for 

diacetyl, 5.3 ppb for 2,3-pentanedione, and 5.7 ppb for 2,3-hexanedione for a typical fullshift air sample. The LODs for the second visit were 0.01 μg/sample for diacetyl, 0.012 μg/ 

sample for 2,3-pentanedione, and 0.02 μg/sample for 2,3-hexanedione; these were based on 

variability of low-level spiked samples. These equate to 0.32 ppb for diacetyl, 0.33 ppb for 

2,3-pentanedione, and 0.48 ppb for 2,3-hexanedione for a typical full-shift TWA air sample. 

The LOQs for the second trip equate to 1.1 ppb for diacetyl, 1.1 ppb for 2,3-pentanedione, 

and 1.6 ppb for 2,3-hexanedione for a typical full-shift air sample. 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. 
Health Hazard Evaluation Report 2015-0082-3287 Page 9 

Air Sampling and Analysis Using Evacuated Canisters 

We collected personal and area full-shift air samples (during the first visit) and instantaneous 

task-based and source air samples (during both visits) 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 with either a restricted flow controller set at a 

15-minute or 6-hour duration (first visit only), or an instantaneous flow controller that was 

designed for a short sampling duration (less than 30 seconds). Instantaneous samples were 

taken by opening the evacuated canister to grab a sample of air to help identify point sources 

of alpha-diketones. For task-based air samples, a NIOSH employee placed the inlet of the 

flow controller by the employee’s personal breathing zone as they performed their work task 

to replicate exposure. For source air samples, a NIOSH employee placed the inlet of the flow 

controller directly at the source of interest. 

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

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

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

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

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

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

the standard method. For the first visit, the LODs were 0.84 ppb for diacetyl, 1.38 ppb for 

2,3-pentanedione, and 2.49 ppb for 2,3-hexanedione based on a three-times dilution factor, 

which is typical for restricted flow controller samplers. For the second visit, 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 Air Sampling 

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

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

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

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

where coffee could be releasing TVOCs. Areas where higher concentrations of TVOCs are 
Page 10 Health Hazard Evaluation Report 2015-0082-3287

measured may benefit from further sampling to characterize specific exposures to alphadiketones. We found increased concentrations around areas that stored roasted coffee, 

especially the storage bins, and areas where grinding occurred. We also collected real-time 

measurements of CO2

, CO, temperature, and relative humidity (RH) using TSI Incorporated 

(Shoreview, MN) VelociCalc Model 9555-X Multi-Function Ventilation Meters equipped 

with Model 982 IAQ probes. 

Area Air Sampling and Analysis for Inhalable and Respirable Dust (1st visit only) 

We collected area air samples for inhalable dust using the Institute of Occupational Medicine 

(IOM) sampler loaded with a pre-weighed 25-mm polyvinyl chloride filter with air pulled 

through the filter at a flow rate of 2 liters per minute (LPM) during our first visit in July 2015. 

Inhalable dust samples were collected and weighed following NIOSH Method 0500 [NIOSH 

2003]. Air samples for respirable dust were collected using a GK 2.69 cyclone (Waltham, 

MA) mounted onto a close-face, two-piece cassette loaded with a 37-mm polyvinyl chloride 

filter with air pulled through the filter at a flow rate of 4.2 LPM. Respirable dust samples 

were collected and weighed following NIOSH Method 0600 [NIOSH 2003]. 

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

American Conference of Governmental Industrial Hygienists (ACGIH®) 

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

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

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

called threshold limit values (TLVs) [ACGIH 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 
Health Hazard Evaluation Report 2015-0082-3287 Page 11 

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]. RELs are intended to 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

2012; Morgan et al. 2012]. The 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, 

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

NIOSH REL for diacetyl [NIOSH 2016]. 
Health Hazard Evaluation Report 2015-0082-3287

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

surveys, July 2015 and March 2016. 

Compound 

OSHA* ACGIH NIOSH 

PEL TLV STEL REL STEL IDLH 

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

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

2,3-Hexanedione - - - - - -

Total dust 15 mg/m3 - - - - -

Respirable dust 5.0 mg/m3 3.0 mg/m3

‡ - - - -

Inhalable dust - 10 mg/m3

‡ - - - -

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

Carbon 

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

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

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

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

REL=recommended exposure limit; IDLH=immediately dangerous to life or health; 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- or 10­

hour day, during a 40-hour workweek.

‡ACGIH does not have a TLV for inhalable or respirable dust but does provide guidelines for inhalable 

and respirable dust; ACGIH guidelines suggests airborne concentrations be kept below 3 mg/m3 for 

respirable particles and 10 mg/m3 for inhalable particles.

§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 

We collected physical measurements of all rooms and calculated approximate room volumes. 

Air flow measurements of supply vents and exhaust outlets were taken using an Accubalance 

Plus Model 8373 Air Capture Hood (TSI Incorporated, St. Paul, MN) or a TSI VelociCalc 

Plus Model 8324 Rotating Vane Anemometer (Shoreview, MN), depending on which 

was most appropriate for the ventilation component being measured. The complete set of 

ventilation measurements allowed the calculation of volumetric flow rates in cubic feet per 

minute (cfm) into and out of each area. Differential pressure measurements between adjacent 

spaces were taken under various ventilation scenarios using an Energy Conservatory DG-500 

Pressure Gauge (Minneapolis, MN). 

Informal Interviews during First Site Visit in July 2015 

A NIOSH medical officer conducted private individual interviews with 22 employees about 

their work history and health concerns. 

Page 12 
Health Hazard Evaluation Report 2015-0082-3287 Page 13 

 

 

NIOSH Medical Survey 

Participants 

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

March 14-16, 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 

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 [NCHS 2015]. Some of the questions appeared on more than one of 

the standardized questionnaires. We also supplemented our questionnaire with additional 

respiratory and systemic symptom questions. 

Spirometry 

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

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

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

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

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

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

et al. 2005]. 

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

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

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

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), 
Page 14 Health Hazard Evaluation Report 2015-0082-3287

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

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

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

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

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

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

contraindication. 

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

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

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

impulse oscillometry testing machine sends sound waves called pressure oscillations at 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Bronchodilator Reversibility Testing for Impulse Oscillometry and Spirometry 

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

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

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

(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 
Health Hazard Evaluation Report 2015-0082-3287 Page 15 

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

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

denoted by a “<” symbol. 

Medical Survey 

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

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

prevalences of symptoms and spirometric abnormalities among participants to expected 

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

symptom and spirometry data), NHANES 2007–2012 (symptom data), and NHANES 2007– 

2010 (spirometry data) 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 U.S. 

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

Results 

Industrial Hygiene Survey Results 

Personal and Area Full-shift Air Sampling Results 

OSHA Methods 1013/1016 

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

first visit in July 2015. We collected 23 personal and 30 area full-shift air samples over three 

days. Two personal air samples were above the NIOSH REL for diacetyl of 5.0 ppb and 

all were below the NIOSH REL for 2,3-pentanedione of 9.3 ppb. The samples exceeding 

the REL for diacetyl were collected on different days. A roaster operator had the highest 

exposure to diacetyl (7.2 ppb) and 2,3-pentanedione (6.9 ppb). A grinder operator had the 

second highest exposure to diacetyl (5.3 ppb) and 2,3-pentanedione (3.7 ppb). All personal 

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

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

Second visit: Table A2 presents the personal and area full-shift air sampling results from our 

second visit in March 2016. We collected 26 personal and 41 area full-shift air samples over 

three days. Eight of the 26 personal air samples (31%) exceeded the NIOSH REL for diacetyl 

of 5.0 ppb and all were below the NIOSH REL for 2,3-pentanedione of 9.3 ppb. The samples 

exceeding the diacetyl REL were collected on different days (two on day 1, five on day 2, and 

one on day 3). Overall, weigh/package employees had the highest exposure to diacetyl and 

2,3-pentanedione. The 11 weigh/package employee measurements for diacetyl ranged from 
Page 16 Health Hazard Evaluation Report 2015-0082-3287

3.1 ppb – 8.4 ppb; seven (64%) of these exceeded the NIOSH REL for diacetyl. All weigh/ 

package employee measurements for 2,3-pentanedione were below the NIOSH REL. One 

of five roaster operator measurements for diacetyl (5.1 ppb) was above the NIOSH REL. 

All personal samplers were below the LOD for 2,3-hexanedione. The difference in personal 

sample results between the first and second visits is likely due to differences in sampling 

conditions including an increase in production volume, decreased natural ventilation caused 

by closed bay doors, and not continuously operating the ceiling exhaust fan in the production 

area. 

Area sampling showed the storage/holding area had the highest air concentrations of diacetyl 

with a range of 9.4 ppb – 10.7 ppb. The range was 5.0 ppb – 5.8 ppb for 2,3-pentanedione 

and less than 0.5 ppb – 0.6 ppb for 2,3-hexanedione. The weigh/package area had air 

concentration of 2,3-pentanedione with a range of 0.8 ppb – 4.7 ppb. All area samples in the 

weigh/package areas were below LOD for 2,3-hexanedione. 

Full-shift Evacuated Canisters 

First visit: Table A3 presents the personal and area full-shift air concentrations from our 

first visit in July 2015 by location. We collected 10 personal and 31 area TWA air samples. 

None were above the NIOSH RELs for diacetyl or 2,3-pentanedione. An employee 

involved in weighing and packaging activities had the highest exposure to diacetyl (4.9 

ppb) and 2,3-pentanedione (8.3 ppb). A roaster operator had the second highest exposure 

to diacetyl (3.6 ppb). An employee involved in multiple tasks labeled “All Over” had the 

second highest exposure to 2,3-pentanedione (3.7 ppb). All area air samples for diacetyl and 

2,3-pentanedione were below 4.0 ppb. The grinding area had the highest concentration of 

diacetyl (3.3 ppb) and 2,3-pentanedione (3.8 ppb). 

Second visit: We did not collect personal or area full-shift evacuated canister samples. 

Task-based Air Sampling Results 

OSHA Methods 1013/1016 

First visit: Table A4 presents the personal and area task-based diacetyl, 2,3-pentanedione, 

and 2,3-hexanedione air concentrations from our first visit in July 2015 by task location. We 

collected 20 personal and 18 area air samples. An employee that ground roasted beans for 17 

minutes had an exposure to diacetyl of 26.9 ppb, which exceeded the NIOSH STEL, and to 

2,3-pentanedione of 18.2 ppb. An employee that weighed and packaged roasted beans for 11 

minutes had the second highest exposure to diacetyl (23.1 ppb) and 2,3-pentanedione (10.9 

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

All task-based area air samples were below the LOD. Area air samples from the roasting area 

(N=15) were collected directly above the downdraft cooling drum of the roaster while the 

roasted beans cooled. 

Second visit: Table A5 presents the personal task-based air concentrations from our second 

visit in March 2016 by individual task. We collected 36 personal task-based air samples. An 

employee that blended roasted beans by hand exceeded the NIOSH STEL for diacetyl (33.4 
Health Hazard Evaluation Report 2015-0082-3287 Page 17 

ppb diacetyl; 22.1 ppb 2,3-pentanedione). An employee that ground roasted beans for 14 

minutes had the highest diacetyl (37.6 ppb) and third highest 2,3-pentanedione (20.9 ppb) 

concentration. This exposure exceeded the NIOSH STEL assuming either the same exposure 

or a zero ppb exposure for the remaining one minute. An employee that ground roasted beans 

for 12 minutes had a personal exposure to diacetyl of 27.9 ppb. This exposure exceeded the 

NIOSH STEL assuming the same exposure for the remaining three minutes. However, this 

exposure did not exceed the NIOSH STEL assuming a zero ppb exposure for the remaining 

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

Evacuated Canisters 

First visit: We collected one personal task-based air sample in July 2015 during the grinding 

process that lasted 15 minutes. 2,3-Hexanedione air concentration was less than the LOD 

(less than 2.3 ppb). Diacetyl (23.6 ppb) and 2,3-pentanedione (11.0 ppb) air concentrations 

were both below their respective NIOSH STELs. This result is not included in the tables. 

Second visit: Table A6 presents the personal task-based air concentrations from our 

second visit in March 2016. All evacuated canisters were equipped with an instantaneous 

flow controller with a sample duration of approximately 30 seconds. Results should not 

be compared to the 15-minute STELs. We collected 14 personal task-based canister air 

samples. We sampled four employees that blended roasted beans by hand who had diacetyl 

concentrations ranging from 15.7 ppb – 193 ppb, 2,3-pentanedione concentrations ranging 

from 19.5 ppb – 90.7 ppb, and 2,3-hexanedione concentrations ranging from 1.5 – 5.3 ppb. 

Blending roasted beans by hand had the highest measured concentration of these task-based 

samples (193 ppb diacetyl; 90.7 ppb 2,3-pentanedione; and 5.3 ppb 2,3-hexanedione). 

We sampled eight employees that transferred roasted beans from storage containers into 

a blending bucket. This task was labelled “Pouring of roasted beans” and had diacetyl 

concentrations ranging from 4.9 ppb – 44.6 ppb, 2,3-pentanedione concentrations ranging 

from 2.6 ppb – 21.2 ppb, and 2,3-hexanedione concentrations ranging from less than 0.9 – 

2.9 ppb. We sampled a single employee that ground roasted beans (64.3 ppb diacetyl; 51.9 

ppb 2,3-pentanedione; and 1.9 ppb 2,3-hexanedione). We sampled a single employee that 

was packaging roasted beans (69.7 ppb diacetyl; 80.5 ppb 2,3-pentanedione; and 5.5 ppb 

2,3-hexanedione). 

Source Air Sampling Results 

OSHA Methods 1013/1016 

First visit: We collected four source air samples from inside roasted bean storage bins during 

our July 2015 visit with a sample duration of 15 minutes. These results are not included 

in the tables. Diacetyl concentrations ranged from 33.1 ppb – 308 ppb; 2,3-pentanedione 

concentrations ranged from 44.0 ppb – 206 ppb; and 2,3-hexanedione concentrations ranged 

from 5.2 ppb – 12.5 ppb. 

Second visit: Source air samples were not collected using OSHA Methods 1013/1016. 
Page 18 Health Hazard Evaluation Report 2015-0082-3287

Evacuated Canisters 

First visit: Table A7 presents the source air sampling results using instantaneous 

evacuated canisters. We followed a French roast source that measured lower diacetyl and 

2,3-pentanedione concentrations when it was hot (Roasting #3 8.9 ppb diacetyl) than when it 

was cooled and placed in a transfer bucket (Roasting #4 109 ppb diacetyl or Roasting #2 87.1 

ppb diacetyl). The two samples from the cooled French roast were sampled sequentially. We 

captured two samples from a grinding source with air concentrations of 146 ppb and 521 ppb 

for diacetyl and 113 ppb and 229 ppb for 2,3-pentanedione. We collected 30 instantaneous air 

samples directly inside the roasted bean storage bins. Diacetyl air concentrations ranged from 

99.4 ppb – 7,011 ppb; 2,3-pentanedione air concentrations ranged from 47.0 ppb – 4,419 ppb, 

and 2,3-hexanedione air concentrations ranged from 5.0 ppb – 219 ppb. 

Second visit: Table A8 presents source air sampling results using instantaneous 

evacuated canisters from our March 2016 visit. We collected 20 source air samples using 

instantaneous evacuated canisters. Two samples were collected directly above roasted 

beans in the downdraft cooling drum (9.3 ppb and 6.0 ppb for diacetyl; 3.0 and 3.3 ppb 

for 2,3-pentanedione). Six samples were collected at the lip of open roasted bean transfer 

containers with diacetyl concentrations ranging from 0.5 ppb – 30.5 ppb (0.6 ppb – 18.6 

ppb for 2,3-pentanedione). Five samples were collected at the discharge point of the grinder 

during grinding with diacetyl concentrations ranging from 127 ppb – 520 ppb (124 ppb – 462 

ppb for 2,3-pentanedione). Four samples were collected during the transfer of roasted beans 

into the top of roasted bean storage bins (3.4 ppb – 184 ppb for diacetyl; 12.2 ppb – 98.0 ppb 

for 2,3-pentanedione). Three samples were collected at the transfer point of roasted beans 

into a bucket (10.9 ppb – 23.7 ppb for diacetyl; 6.3 ppb – 17.5 ppb for 2,3-pentanedione). 

2,3-Hexanedione concentrations were generally less than diacetyl and 2,3-pentanedione 

concentrations and ranged from less than 0.9 ppb to 35.6 ppb. 

Background Pre- and Post-Shift Diacetyl and 2,3-Pentanedione Canister Results 

Table A9 presents the instantaneous evacuated canister pre- and post-shift background air 

sampling results from our second visit collected in the storage/holding area. Both diacetyl 

and 2,3-pentanedione air concentrations increased over the course of the work day. The 

pre-shift diacetyl concentration was 3.5 ppb and post-shift air concentration was 15.5 ppb. 

The pre-shift 2,3-pentanedione air concentration was 1.6 ppb and post-shift air concentration 

was 8.5 ppb. 2,3-Hexanedione was below the LOD (<0.6 ppb) for both pre- and post-shift 

measurements. 

Bulk Samples and Headspace Results 

Table A10 presents the bulk sample results using headspace analysis from our two visits. 

Overall, bulk samples from the second visit contained higher headspace air concentrations 

of diacetyl and 2,3-pentanedione than the first visit. The higher concentrations from the 

samples collected in March 2016 may be in part due to the fact that the samples were 

analyzed within 40 days of collection, approximately three times faster than the bulk samples 

from the first visit. The highest air concentrations of diacetyl (2,069 ppb and 2,012 ppb) 

and 2,3-pentanedione (1,350 ppb and 1,042 ppb) were associated with whole roasted bean 

#10. Green coffee beans did not have any air concentrations of diacetyl or 2,3-pentanedione. 
Health Hazard Evaluation Report 2015-0082-3287 Page 19 

2,3-Hexanedione concentrations were generally below the LODs (19 of 22 air samples) or 

lower than 2,3-pentanedione when above the LOD. 

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

Organic Compounds (TVOCs) 

First visit: Table A11 presents the results from real-time monitoring for CO, CO2

, 

temperature, and RH collected in July 2015. Indoor CO levels ranged from 0.7 ppm – 1.6 

ppm; the outdoor CO level was less than 0.1 ppm. CO2

 levels within the facility ranged 

from 800 ppm – 820 ppm, with the outdoor CO2

 at 430 ppm. When the real-time monitor 

was placed directly inside roasted coffee bean storage bins, we observed elevated levels 

of CO2

 (540 ppm – 5,200 ppm) and CO (130 ppm – 410 ppm). We did not collect TVOC 

measurements during our first visit. 

Second visit: Table A12 presents the results from real-time monitoring of CO2

, CO, 

temperature, and RH collected in March 2016. Average CO2

 levels at the roasting machines 

were 502 ppm and 463 ppm over two days, and average CO levels were 0.8 ppm and 0.3 

ppm. The roasted bean storage area had an average CO2

 level of 599 ppm and an average CO 

level of 2.4 ppm. In addition, we found increased concentrations of TVOCs around areas that 

stored roasted coffee, especially the storage bins, and areas where grinding occurred (data not 

shown). 

Area Air Sampling and Analysis for Inhalable and Respirable Dust (1st visit only) 

Table A13 presents the area dust sampling results from our July 2015 visit by location. 

All area air samples for respirable and inhalable dust were below OSHA and ACGIH 

occupational exposure limits. We did not observe any visible dust in the air; however, we did 

observe dust on surfaces during this visit.
	

Ventilation Assessment
 

First visit: There was adequate total air flow to and from all occupied areas on the office side 

of the facility to maintain temperature control in July 2015. 

The ventilation on the production side of the facility consisted of one large rooftop make-up 

air system providing ventilation to the space and one exhaust fan through the eastern wall 

of the facility. The ventilation plans for the facility call for the make-up air system to be 

interlocked so that it is always operational when the roasters are on. This may be the case, 

but it was not specifically verified during our visit. Regardless, it was operational while we 

were onsite and provided 3,030 cfm of air into the production area. The exhaust fan was 

reported to be operated intermittently depending on employee preferences and comfort level. 

When on, the exhaust fan removed 1,850 cfm of air from the production area. It should be 

noted that these measurements were taken while the bay doors on both ends of the production 

space were open, as is typical for the summer months. This made determining any pressure 

relationships between the production space and office areas unrepresentative.
	

Although the ventilation systems were well maintained, we did notice an area of concern 

regarding the afterburner stacks from the roasters in July 2015. While we were outside 
Page 20 Health Hazard Evaluation Report 2015-0082-3287

checking on an area sample, the parking lot was briefly filled with thick smoke. Upon 

investigating the smoke from the parking lot, we found that the afterburner stack for 

one of the roasters was smoking due to a build-up of chaff residue (Figure B1). During 

our inspection on the roof, we also noted that the other roaster exhaust stack was also 

significantly plugged with chaff and debris (Figure B2). In our first interim report, 

we recommended that the exhaust stacks be cleaned in accordance with manufacturer 

instructions to prevent possible safety hazards, improve roaster performance, and enhance 

energy efficiency. 

Second visit: During our second visit in March 2016, total air flow to and from all occupied 

areas on the office side of the facility were roughly 10% to 15% lower than the values 

measured in July 2015. Even in the winter months, the three air-handling units on the office 

side were easily capable of maintaining temperature control. 

During the March 2016 visit, the make-up air handling unit was supplying 2,585 cfm of air 

into the production space. The exhaust fan was not being operated during our visit, so we did 

not turn it on to measure air flow. The bay doors on both ends of the production space were 

down during this visit, as is typical for the winter months. This made determining pressure 

relationships between the production space and office areas possible. Differential pressure 

measurements showed that the production space was neutral or under slightly positive 

pressure in relationship to the administrative side of the facility. The pressure readings across 

all doorways between the production space and the office side of the facility were all +0.002 

inches of water. 

We inspected the roaster exhaust stacks again during our March 2016 visit. It was obvious 

that the stacks had been cleaned in response to our recommendation after the July 2015 visit. 

Both exhaust stacks were largely clean and clear of debris. 

Informal Employee Interviews during July 2015 Site Visit 

Twenty-two of 26 onsite employees were interviewed individually. Some employees noted 

symptoms that they attributed to work: occasional sneezing due to odors, sinus problems 

due to green coffee dust, and skin issues due to cardboard or roasted coffee beans. Diagnoses 

reported among interviewed employees included seasonal allergies, asthma, and COPD. 

Approximately half noted they were current or past smokers. Some employees in production 

noted that once they completed the tasks for their primary job title, they often helped with 

other production tasks, or sometimes, they would fill-in if someone was absent for the 

day. On any given day, some supervisors also helped, as needed, with production tasks 

(e.g., roasting, grinding, weighing, and/or packaging). Some office employees started at 

the company in coffee processing jobs before moving to office positions. Some employees 

reported working at another coffee roasting and packaging facility before working at this 

facility. Multiple employees noted that hearing protection was available for voluntarily use 

when roasting. 
Health Hazard Evaluation Report 2015-0082-3287 Page 21 

Medical Survey Results March 2016 

Demographics 

Sixteen of 25 onsite employees (64%) participated in the medical survey, including six of 

12 production employees. The majority of participants were male (75%) and Caucasian 

(88%), with a mean age of 38 years and average tenure at the company (including previous 

locations) of four years. Four (25%) participants worked at one or more of the company’s 

prior locations or at another coffee roasting and packaging facility prior to working at this 

facility. Ten (63%) participants were current or former smokers. 

All 16 participants reported working in or entering the production area, ranging from 30 

minutes 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. Six of 16 participants worked full-time in 

the production area processing coffee while some of the other participants assisted with 

production activities when necessary. 

Symptoms and Self-Reported Diagnoses 

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

are listed in Table A14. Nose symptoms were the most commonly reported symptom (n=13, 

81%), followed by eye symptoms (n=8, 50%) and sinusitis or sinus problems (n=7, 44%). 

Five participants reported improvement in their symptoms away from the workplace. Some 

production employees noted that their symptoms were caused or aggravated by green coffee 

bean dust, chaff, particular blends of roasted coffee, grinding coffee, ground coffee dust, or an 

odor from a heat sealing machine used to seal individual bags of coffee. 

Wheeze was the most commonly reported lower respiratory symptom (n=9, 56%). None 

reported improvement in wheeze away from the workplace. Four (n=4, 25%) participants 

reported shortness of breath, while fewer reported usual cough or phlegm. Flu-like achiness 

or achy joints was the most commonly reported systemic symptom (n=11, 69%). Two (13%) 

participants reported that their systemic symptoms were aggravated at work or better when 

away from work. 

Nine participants reported a diagnosis of hay fever or nasal allergies; three reported COPD or 

asthma. All these conditions were diagnosed prior to employment at the coffee roasting and 

packaging facility. No participants reported a diagnosis of chronic bronchitis, bronchiolitis 

obliterans, interstitial lung disease, hypersensitivity pneumonitis, chemical pneumonitis, 

sarcoidosis, heart disease, or vocal cord dysfunction. 

Medical Tests 

One spirometry test was interpreted as having an obstructive pattern, with significant 

improvement after bronchodilator. Based on this finding and on questionnaire responses, 

flavoring-related lung disease was thought to be unlikely. One impulse oscillometry test 

was interpreted as consistent with a large airway abnormality. Four impulse oscillometry 

tests, including one performed by the participant with abnormal spirometry, were interpreted 

as consistent with small airway abnormality; three of these four participants were given 

bronchodilator, and two had significant improvement in impulse oscillometry. One exhaled 
Page 22 Health Hazard Evaluation Report 2015-0082-3287

nitric oxide test was interpreted as elevated. Most of the participants with abnormalities on 

medical tests were current or former smokers and reported lower respiratory symptoms, such 

as wheezing, that did not improve away from work. 

NHANES Comparison of Symptoms, Diagnoses, and Spirometry 

The SMR for wheeze was elevated at 4.5 (Table A15). SMRs for cough, phlegm, sinus 

problems, eye symptoms, and physician-diagnosed asthma were not elevated. In addition, 

there was not an excess of obstructive spirometry abnormalities in comparison to the general 

U.S. population, adjusted for age distribution, race/ethnicity, sex, and smoking history. 

Discussion 

Diacetyl, 2,3-pentanedione, 2,3-hexanedione, other VOCs, and other chemicals such as CO 

and CO2

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

coffee beans produces greater surface area for the off-gassing of these chemicals [Anderson 

et al. 2003; Akiyama et al. 2003; Daglia et al. 2007; Newton 2002; Nishimura et al. 2003; 

Raffel and Thompson 2013]. Occupational exposure to diacetyl and 2,3-pentanedione can 

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

Alpha-Diketones 

Personal Air Sampling 

Ten personal (two roaster operator, one grinder operator, and seven weigh/package employee 

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

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

was 8.4 ppb collected from a weigh/package employee during the second site visit. This 

elevated average exposure was likely due to peak exposures that occurred during handling 

and transferring roasted coffee beans combined with periods of lower exposures. As noted 

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

reduce exposures in the workplace. The risks 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 higher 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]). The effects of a working lifetime exposure at 8.4 ppb would be somewhat less than 

those for 10 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. 

Overall, personal exposures to diacetyl and 2,3-pentanedione were higher during our second 

visit compared to our first visit. Alpha-diketone emissions of diacetyl and 2,3-pentanedione 
Health Hazard Evaluation Report 2015-0082-3287 Page 23 

into the workplace air were directly related to the amount of roasted coffee being produced. 

During the second visit, the company was roasting and processing more coffee than during 

the first visit. Since more beans were being roasted and subsequently packaged, weigh/ 

package employees were handling roasted beans more often, which may have resulted in 

elevated exposures compared to our first visit. Additionally, during our first visit in July 2015, 

the company left the two production bay doors open to assist in reducing potential exposures 

and keeping employees cool during warm weather. However, during our second visit in 

March 2016, the two bays were closed, which likely caused diacetyl and 2,3-pentanedione to 

build up over the work shift. Additionally, the large exhaust fan in the production space was 

not operating. 

During both visits, the roaster operators often remained at the roaster control panels during 

the roasting process, approximately three feet from each roaster. Each roasting drum was 

fully enclosed, and air was exhausted through the roof, minimizing exposures indoors. The 

only time the roasting drum was opened was during the transfer of roasted beans into the 

cooling drum. The downdraft system on the roaster machines pulled air over the roasted 

beans and down into the cooling drum to accelerate cooling which likely decreased the 

roaster operator’s exposure. During both visits, all roasting area samples (Tables A1 and A2) 

had low concentrations of diacetyl and 2,3-pentanedione indicating the effectiveness of the 

roasters’ downdraft exhaust system. 

Two full-shift personal air sample diacetyl and 2,3-pentanedione measurements of roaster 

operators (one during each visit) were higher than other samples of roaster operators. Peak 

exposures to diacetyl and 2,3-pentanedione likely contributed to the higher full-shift air 

sample results for these two employees; throughout the shift, these roaster operators emptied 

buckets of freshly roasted coffee beans into roasted coffee bean storage bins. The roasted 

coffee beans off-gassed in these bins. We measured high instantaneous concentrations of 

diacetyl (99.4 ppb – 7,011 ppb) and 2,3-pentanedione (47.0 ppb – 4,419 ppb) inside the 

roasted bean storage bins (Table A7). Since these samples were collected inside the storage 

bins, they were not reflective of employee exposure, but they do indicate an off-gassing 

source of alpha-diketones. 

Both of these higher personal full-shift air samples for the roaster operators exceeded 

a personal full-shift air sample for a grinder operator. During both visits, grinding was 

performed infrequently because the majority of sales were whole bean. During task-based 

air sampling, an employee that ground roasted beans for 14 minutes had the highest diacetyl 

(37.6 ppb) and third highest 2,3-pentanedione (20.9 ppb) levels. If grinding tasks were 

performed more often, full-shift air concentrations for the alpha-diketones may have been 

higher; this was the case at another coffee roasting and packaging facility NIOSH evaluated 

[Duling et al. 2016]. 

Area Air Sampling 

Area samples collected from the storage/holding area, where package coffee was stored, 

were higher during our second visit (Table A2) compared to our first visit (Table A1). 

The increased volume of roasted beans in the storage/holding area during the second visit 
Page 24 Health Hazard Evaluation Report 2015-0082-3287

likely led to more off-gassing of diacetyl and 2,3-pentanedione, as reflected in the area 

sampling results. The closed bay doors as well as the non-functioning large exhaust fan in 

the production space also likely contributed to the increased concentrations of diacetyl and 

2,3-pentanedione. 

Task-Based Exposures 

Coffee processing involves multiple tasks that may cause intermittent exposure to 

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

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

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

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

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

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

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

higher exposures to diacetyl and 2,3-pentanedione. 

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

diacetyl and/or 2,3-pentanedione than other tasks. During our second visit, packaging 

coffee tasks had higher levels of diacetyl and 2,3-pentanedione compared to the first visit. 

Using OSHA Methods 1013/1016, packaging coffee tasks resulted in air concentrations of 

diacetyl ranging from 3.0 ppb – 34.3 ppb and 2,3-pentanedione ranging from less than 1.0 

ppb – 28.4 ppb (Table A5). As previously stated, during our second visit, the company was 

processing more coffee than the first visit, which likely contributed to the higher exposures 

during weigh/package tasks. Employees often had to weigh and pack different blends of 

roasted beans. For orders requiring mixtures of different roasted coffee beans, blends were 

completed by using the agitator arm of a cooling drum to automatically blend roasted 

beans or by blending roasted beans by hand inside a plastic tote. An employee’s bending 

over and placing their head above the tote while blending the roasted beans by hands likely 

contributed to higher measured alpha-diketones. Using instantaneous evacuated canisters, 

we also observed that blending by hand resulted in the highest diacetyl (maximum 193 ppb) 

and 2,3-pentanedione (maximum 90.7 ppb) air concentrations compared to other tasks (Table 

A6). 

During our first visit, we observed maximum levels of CO at 410 ppm and CO2

 at 5200 ppm 

directly inside roasted bean storage bins (Table A11). During our second visit, we monitored 

CO and CO2

 levels in specific work areas over the course of the day (Table A12). Although 

CO and CO2

 levels were high inside the roasted bean storage bins, CO and CO2 were 

generally low throughout the other areas of the facility. However, during our second visit we 

noticed a slight increase in CO and CO2

 when we left the real-time monitor in the roasted 

bean storage area for the day, likely caused by the close proximity to the off-gassing roasted 

beans. We recommend employees do not place their head or face inside the bins. 

Bulk Samples 

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

al. 2007]. As expected, we found that roasted coffee emits alpha-diketones into the headspace 
Health Hazard Evaluation Report 2015-0082-3287 Page 25 

of sealed vessel, indicating that roasted coffee is a considerable source of alpha-diketones 

in the facility. We observed lower levels of alpha-diketones from headspace analysis of 

bulk roasted coffee samples from our first visit; however, caution should be taken when 

interpreting these results because bulk samples collected during our first visit were not 

analyzed immediately after sampling, and the samples had time to off-gas prior to performing 

the headspace analysis. We also do not know how long the beans were in the storage bins 

prior to collecting the samples, but generally the time between roasting and packaging is 

on the order of hours to days. The amount of time roasted beans had off-gassed could be 

responsible for differences in headspace analysis results. 

Dust 

Although area inhalable and respirable dust concentrations were below OSHA and ACGIH 

occupational exposure limits, coffee dust, even at low concentrations, is 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 et al. 1991]. People 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]. 

Ventilation 

The ventilation systems serving the administrative areas provided adequate total air flow to 

maintain temperature control during both visits. However, we did not have the equipment 

to accurately determine the amount of fresh, outdoor air being supplied to those spaces. 

Measured levels of CO2

 in the administrative spaces were all 790 ppm or below (well less 

than 700 ppm above the 430 ppm measured outside), which provides an indication that 

adequate fresh, outdoor air was being supplied. 

In March 2016, we determined that air from the production side can flow into the 

administrative areas, although the production space was neutral to only slightly positive to 

the administrative side of the facility under the conditions of testing. As noted earlier the 

large exhaust fan in the production space was not operating at the time the measurements 

were taken. Operating the exhaust fan would likely change these differential pressures or 

cause the production space to be negative compared to the administrative areas, which 

is desirable. Also, it should be noted that large cooling fans were being operated in the 

roasting and packaging areas to keep employees cool, and this could easily have an impact 

on the differential pressure measurements. While the pressure relationships did show that 

contaminated air from the production area can migrate into the administrative areas, none of 

our personal or area sampling results indicated elevated exposures to office workers. 

In looking at our sampling results with regard to ventilation, the pre- and post-shift canister 

samples (see Table A9) taken in March 2016 showed that the concentrations of diacetyl 

and 2,3-pentanedione increased over the course of the work shift. This indicates that the 

generation rate of these compounds exceeded the rate at which ventilation removed them 
Page 26 Health Hazard Evaluation Report 2015-0082-3287

under the conditions when the samples were taken. Operating the large production area 

exhaust fan would likely impact this result. Likewise, operating with the bay doors open at 

either end of the production area would have an impact on this result. Another similar finding 

was that the levels of alpha-diketones we measured in area samples were generally higher in 

March 2016 compared to July 2015. Again, this is likely the result of the production space 

being sealed up with no exhaust air flowing from the space and the increase in production 

volume during the second visit. 

Medical Survey 

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

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

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

or roasted coffee dust. Coffee dust is an organic dust and, as noted earlier, exposure to coffee 

dust is known to cause respiratory symptoms and is a known risk factor for occupational 

asthma [Karr et al. 1978; Zuskin et al. 1979, 1985, 1993; Thomas et al. 1991; Sakwari et al. 

2013]. 

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 2008; 

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

sinusitis) can result in suboptimal control of asthma. All 10 participants that reported lower 

respiratory symptoms also reported nasal or sinus problems or physician-diagnosed hay fever 

or nasal allergies. Green coffee dust is thought to be a more potent allergen than roasted 

coffee dust because roasting destroys some of the allergenic activity [Lehrer et al. 1978]. As 

discussed in the recommendations section, to prevent symptoms related to green coffee dust 

and chaff, make N-95 disposable filtering-face piece respirators available for voluntary use 

when emptying burlap bags of green beans into the storage silos or when emptying the chaff 

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, 63% (n=10) of participants (including participants 

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

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

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

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

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

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

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

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

is intermittent airways obstruction which is reversible after treatment with bronchodilator 

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

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

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

prevent rapid emptying of the lung air sacs (alveoli) during exhalation. This explains why 
Health Hazard Evaluation Report 2015-0082-3287 Page 27 

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

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

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

Spirometry and impulse oscillometry measure different things. Spirometry assesses 

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

Our findings of upper respiratory symptoms with a work-related pattern in many employees, 

four-fold excess of wheeze, and abnormalities on lung function testing in about a third of 

participants suggest a burden of respiratory problems in this workforce. The upper respiratory 

symptoms that improve away from work are likely related to workplace exposures. However, 

the lower respiratory symptoms such as wheeze did not have a work-related pattern. These 

lower respiratory symptoms and the lung function abnormalities we found 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, and there were a number 
Page 28 Health Hazard Evaluation Report 2015-0082-3287

of participants with abnormal breathing tests or history of lower respiratory symptoms. 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, if they choose to share these results with 

the provider. In a workplace with risk of occupational lung disease, prevention of smokingrelated lung disease is important and makes the detection of work-related adverse effects 

easier. The Centers for Disease Control and Prevention offers tools and resources for setting 

up a smoking cessation program [CDC 2017]. 

Conclusions 

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

the NIOSH REL and STEL. Grinding roasted coffee beans, blending roasted coffee beans 

by hand, and weighing and packaging roasted coffee were associated with higher diacetyl 

levels, likely due to the close proximity of the employee’s breathing zone to the roasted 

beans. CO and CO2

 levels were low throughout most of the facility, and the highest CO and 

CO2

 levels were observed at the openings of roasted bean storage bins; however, this may not 

be representative of employee exposure. Area inhalable and respirable dust concentrations 

were below OSHA and ACGIH occupational exposure limits; however, coffee dust, even at 

low concentrations, is known to cause respiratory symptoms and is a known risk factor for 

occupational asthma. Overall, full-shift air concentrations of diacetyl and 2,3-pentanedione 

were consistently higher during our second industrial hygiene survey in March 2016 when 

the bay doors were down. Air concentrations increased over the course of the work day, 

indicating opening the bay doors, if weather permits, may help decrease the accumulation of 

diacetyl and 2,3-pentanedione over the day. Recommendations are made to reduce worker 

exposure and protect respiratory health. 

Ventilation measurements supported sampling results which showed the air concentrations 

of alpha-diketones (e.g., diacetyl, 2,3-pentanedione, 2,3-hexanedione) were higher in March 

2016 than during our initial visit in July 2015 when the bay doors were open. Increased 

production during the second visit may also have contributed to the increase in measured 

air concentrations of alpha-diketones. In March 2016, pressure measurements showed that 

the production space was under neutral to slightly positive pressure to the office areas, 

which could allow contaminated air from production activities to flow into the offices. This 

pressure relationship is not ideal. It is likely that these results were related to the fact that 

the large exhaust fan in the production space was off and the two bay doors at either end of 

the plant were closed in March 2016. Simply operating the exhaust fan at all times during 

production activities would help reduce airborne contaminants in the space and reduce the 

pressure in the production space relative to the administrative side of the facility. Operating 

with the bay doors open when weather permits would serve to further dilute contaminants 
Health Hazard Evaluation Report 2015-0082-3287 Page 29 

in the production space; however, the impact on pressure relationships would be variable, 

depending on weather conditions outdoors. 

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

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

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

or ground coffee dust. Wheezing or whistling in the chest was the most commonly reported 

lower respiratory symptom. A statistically significant four-fold excess of wheezing existed 

in the participants compared to the U.S. noninstitutionalized population of the same age, 

race/ethnicity, sex, and cigarette smoking distribution. Six of 16 medical survey participants 

had abnormal breathing tests. 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. 

1. Operate the make-up air unit and the large exhaust fan in the production space 

continuously during the work shift. Operating this equipment in combination will 

help dilute and remove airborne alpha-diketones (e.g., diacetyl, 2,3-pentanedione, and 

2,3-hexanedione) as they are generated and help maintain the production space under 

negative pressure relative to the administrative offices. 

2. When seasonally possible, open the bay doors to assist in mitigating the accumulation 

of alpha-diketones. 

3. If other engineering and administrative controls (see below) do not reduce air 

concentrations of alpha-diketones, work with a ventilation engineer to install local 

exhaust ventilation during the following tasks: 
Page 30 Health Hazard Evaluation Report 2015-0082-3287

a.		 blending roasted coffee by hand; 

b.		 grinding roasted coffee; and 

c.		 weighing and packaging roasted coffee. 

Administrative Controls 

Administrative controls are employer-dictated work practices and policies implemented 

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

commitment and employee acceptance. Regular monitoring and reinforcement are necessary 

to ensure that policies and procedures are followed consistently. 

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

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

usage, and roaster performance. 

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

maintenance schedule to ensure they operate appropriately. 

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

alpha-diketones and other chemicals (e.g., CO, CO2

) into the workplace and lower 

worker exposure. 

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

, minimize 

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

bins. 

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

some other automatic mechanism that minimizes employee contact with roasted beans 

during blending. 

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

cleaning. Instead, use a vacuum system with a high-efficiency particle air filter and wet 

methods whenever possible. 

7. Ensure the guard rail on the platform for the storage bins of roasted coffee beans is in 

use to reduce the risk of falls. 

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. 

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. 
Health Hazard Evaluation Report 2015-0082-3287 Page 31 

Personal Protective Equipment 

Personal protective equipment is the least effective means for controlling hazardous 

exposures. Proper use of personal protective equipment requires a comprehensive program 

and a high level of employee involvement and commitment. The right personal protective 

equipment must be chosen for each hazard. Supporting programs such as training, change-out 

schedules, and medical assessment might be needed. Personal protective equipment should 

not be the sole method for controlling hazardous exposures. Rather, personal protective 

equipment should be used until effective engineering and administrative controls are in place. 

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

potential option to further reduce exposures to alpha-diketones (e.g., diacetyl and 

2,3-pentanedione). If respiratory protection is used, NIOSH-certified respirators should 

be fitted with organic vapor cartridges and particulate filters. The choice of respirator 

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

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

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

air-purifying half-face respirators have an APF of 10, and air-purifying full-face 

respirators have an APF of 50. Also, there are powered-air purifying respirators that 

have APFs of 25, 50, or 1000. The OSHA APFs can be found in Table 1 of OSHA 

Respiratory Protection Standard at https://www.osha.gov/pls/oshaweb/owadisp.show_ 

document?p_id=12716&p_table=STANDARDS. 

If mandatory respiratory protection is used, a written respiratory protection program 

should be implemented as required by the OSHA Respiratory Protection Standard (29 

CFR 1910.134), including training, fit testing, maintenance and use requirements. 

2. Offer employees the voluntary use of N95 disposable filtering-facepiece respirators 

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

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

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

potential N95 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. 

3. We did not formally assess noise during our visits. A noise survey would be necessary 

to determine the need for hearing protection and inclusion in a hearing conservation 

program. In the interim, continue to offer hearing protection for voluntary use at each 

roaster. 
Page 32 Health Hazard Evaluation Report 2015-0082-3287

Medical Monitoring 

The purpose of a medical monitoring program is to help assure the health of employees 

who have workplace exposures (e.g., diacetyl, 2,3-pentanedione, green coffee beans/dust) 

known to pose risk for potentially serious health conditions such as asthma or obliterative 

bronchiolitis. 

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

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]. 

2. If an employee is identified as likely having lung disease from exposure to diacetyl or 

2,3-pentanedione, it should be viewed as a sentinel event indicating that there was a 

breakdown in exposure controls and that there is potential risk for co-workers. Should 

this occur, the unanticipated source of exposure must be identified and brought under 

control. In addition, increased intensity of medical surveillance would be required for 

all employees performing similar job tasks or having similar or greater potential for 

exposure. The NIOSH Criteria Document provides detailed guidance on responses to 

such sentinel events [NIOSH 2016]. 

Smoking Cessation Program 

In a workplace with risk of occupational lung disease, prevention of smoking-related lung 

disease is important and makes the detection of work-related adverse effects easier. We 

recommend implementing a smoking cessation program to assist employees to stop smoking. 

The Centers for Disease Control and Prevention offers tools and resources for setting up a 

smoking cessation program [CDC 2017]. 
Health Hazard Evaluation Report 2015-0082-3287 Page 33 

 

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Health Hazard Evaluation Report 2015-0082-3287

 

Appendix A: Tables 

Table A1. OSHA Methods 1013/1016 full-shift personal and area air sampling results by 

location, 1st NIOSH industrial hygiene survey, July 2015. 

Analyte 

Sample 

 Type 

Location N 

Above 

LOD N 

(%)

 Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Above 

REL 

N 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Personal Administration 

Personal All Over 

Personal Grinding 

Personal Roasting 

Personal Weigh/Package 

3 

4 

1 

6 

9 

0 (0%) <3.1 <3.1 0 

0 (0%) <3.0 <3.2 0 

1 (100%) 5.3 5.3 1 

2 (33%) <3.0 7.2 1 

1 (11%) <=2.9 2.9 0 

Area Administration 5 0 (0%) <3.1 <3.2 -

Diacetyl Area Breakroom 3 0 (0%) <3.0 <3.4 -

Diacetyl Area Grinding 3 0 (0%) <3.1 <3.2 -

Diacetyl Area Outside 3 0 (0%) <3.1 <3.3 -

Diacetyl Area Quality Control 3 0 (0%) <2.9 <3.2 -

Diacetyl Area Roasting 9 0 (0%) <2.8 <3.8 -

Diacetyl Area Storage/Holding 4 0 (0%) <3.0 <3.2 -

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

Personal Administration 

Personal All Over 

Personal Grinding 

Personal Roasting 

Personal Weigh/Package 

3 

4 

1 

6 

9 

0 (0%) <2.5 <2.5 0 

0 (0%) <2.5 <2.6 0 

1 (100%) 3.7 3.7 0 

2 (33%) <2.4 6.9 0 

1 (11%) <=2.1 2.1 0 

Area Administration 5 0 (0%) <2.5 <2.6 -

2,3-Pentanedione Area Breakroom 3 0 (0%) <2.4 <2.7 -

2,3-Pentanedione Area Grinding 3 0 (0%) <2.5 <2.6 -

2,3-Pentanedione Area Outside 3 0 (0%) <2.5 <2.7 -

2,3-Pentanedione Area Quality Control 3 0 (0%) <2.4 <2.6 -

2,3-Pentanedione Area Roasting 9 0 (0%) <2.2 <3.1 -

2,3-Pentanedione Area Storage/Holding 4 0 (0%) <2.4 <2.5 -

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

Personal Administration 

Personal All Over 

Personal Grinding 

Personal Roasting 

Personal Weigh/Package 

3 

4 

1 

6 

9 

0 (0%) <2.5 <2.5 -

0 (0%) <2.5 <2.6 -

0 (0%) <2.5 <2.5 -

0 (0%) <2.4 <3.9 -

0 (0%) <2.4 <3.1 -

Area Administration 5 0 (0%) <2.5 <2.7 -

2,3-Hexanedione Area Breakroom 3 0 (0%) <2.5 <2.7 -

2,3-Hexanedione Area Grinding 3 0 (0%) <2.5 <2.6 -

2,3-Hexanedione Area Outside 3 0 (0%) <2.5 <2.7 -

2,3-Hexanedione Area Quality Control 3 0 (0%) <2.4 <2.6 -

2,3-Hexanedione Area Roasting 9 0 (0%) <2.2 <3.1 -

2,3-Hexanedione Area Storage/Holding 4 0 (0%) <2.5 <2.6 -

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

Occupational Safety and Health; N=number of samples; Above LOD N (%) = number and percentage of 

samples above the limit of detection (LOD); < indicates below the LOD; <= indicates less than or equal 

to the LOD; Above REL N=number of samples above the NIOSH recommended exposure limit (REL); 

ppb=parts per billion; “-“ NIOSH RELs are specified for personal air samples and area air samples 

cannot be used for comparison; “All Over” location includes employees that were cross-trained and 

performed tasks at different areas. 

Page 41 
Health Hazard Evaluation Report 2015-0082-3287

Table A2. OSHA Methods 1013/1016 full-shift personal and area air sampling results by 

location, 2nd NIOSH industrial hygiene survey, March 2016. 

Analyte Sample 

Type Location N 

Above 

LOD N 

(%) 

Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Above 

REL N 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Diacetyl 

Personal Administration 

Personal Grinding 

Personal Production Area 

Personal Roasting 

Personal Weigh/Package 

4 

1 

5 

5 

11 

4 (100%) 0.9 2.6 0 

1 (100%) 3.1 3.1 0 

5 (100%) 1.4 4.8 0 

5 (100%) 3.0 5.1 1 

11 (100%) 3.1 8.4 7 

Area Administration 8 8 (100%) 0.6 3.0 -

Diacetyl Area Breakroom 3 3 (100%) 0.9 2.5 -

Diacetyl Area Grinding 6 6 (100%) 1.9 3.8 -

Diacetyl Area Pack/Ship 3 3 (100%) 2.3 3.9 -

Diacetyl Area Production Area 3 3 (100%) 1.9 2.8 -

Diacetyl Area Quality Control 3 3 (100%) 2.2 3.1 -

Diacetyl Area Roasting 6 6 (100%) 2.8 4.2 -

Diacetyl Area Storage/Holding 3 3 (100%) 9.4 10.7 -

Diacetyl Area Weigh/Package 6 6 (100%) 1.4 5.3 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

2,3-Pentanedione 

Personal Administration 

Personal Grinding 

Personal Production Area 

Personal Roasting 

Personal Weigh/Package 

4 

1 

5 

5 

11 

4 (100%) 0.6 1.9 0 

1 (100%) 2.4 2.4 0 

5 (100%) 1.0 2.8 0 

5 (100%) 2.0 3.4 0 

11 (100%) 1.5 5.7 0 

Area Administration 8 8 (100%) 0.5 1.9 -

2,3-Pentanedione Area Breakroom 3 3 (100%) 0.8 1.8 -

2,3-Pentanedione Area Grinding 6 6 (100%) 1.0 3.1 -

2,3-Pentanedione Area Pack/Ship 3 3 (100%) 1.5 2.8 -

2,3-Pentanedione Area Production Area 3 3 (100%) 1.0 2.0 -

2,3-Pentanedione Area Quality Control 3 3 (100%) 1.2 2.3 -

2,3-Pentanedione Area Roasting 6 6 (100%) 1.9 3.0 -

2,3-Pentanedione Area Storage/Holding 3 3 (100%) 5.0 5.8 -

2,3-Pentanedione Area Weigh/Package 6 6 (100%) 0.8 4.7 -

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

2,3-Hexanedione 

Personal Administration 

Personal Grinding 

Personal Production Area 

Personal Roasting 

Personal Weigh/Pack 

4 

1 

5 

5 

11 

0 (0%) <0.5 <0.5 -

0 (0%) <0.8 <0.8 -

0 (0%) <0.4 <0.5 -

0 (0%) <0.5 <0.5 -

0 (0%) <0.5 <0.8 -

Area Administration 8 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Breakroom 3 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Grinding 6 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Pack/Ship 3 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Production Area 3 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Quality Control 3 0 (0%) <0.5 <0.5 -

Page 42 
Health Hazard Evaluation Report 2015-0082-3287

 

Table A2 cont. OSHA Methods 1013/1016 full-shift personal and area air sampling results by 

location, 2nd NIOSH industrial hygiene survey, March 2016. 

Analyte Sample 

Type Location N 

Above 

LOD N 

(%) 

Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Above 

REL 

N 

2,3-Hexanedione Area Roasting 6 0 (0%) <0.5 <0.5 -

2,3-Hexanedione Area Storage/Holding 3 1 (33%) <0.5 0.6 -

2,3-Hexanedione Area Weigh/Package 6 0 (0%) <0.2 <0.5 -

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

Occupational Safety and Health; N=number of samples; Above LOD N (%)=number and percentage 

of samples above the limit of detection (LOD); Above REL N = number of samples above the NIOSH 

proposed recommended exposure limit (REL); ppb=parts per billion; “-“ NIOSH RELs are specified for

personal air samples and area air samples cannot be used for comparison; < indicates below the LOD. 

Page 43 
Health Hazard Evaluation Report 2015-0082-3287

Table A3. Evacuated canister method time-weighted average personal and area air sampling 

results by location, 1st NIOSH industrial hygiene survey, July 2015. 

Analyte Sample 

Type Location N 

Above 

LOD N 

(%) 

Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Above 

REL 

N 

Diacetyl Personal Administration 1 1 (100%) 3.0 3.0 0 

Diacetyl Personal All Over 2 1 (50%) <0.9 3.1 0 

Diacetyl Personal Delivery 1 1 (100%) 0.6 0.6 0 

Diacetyl Personal Outside 1 0 (0%) <3.4 <3.4 0 

Diacetyl Personal Roasting 2 2 (100%) 1.7 3.6 0 

Diacetyl Personal Weigh/Package 3 3 (100%) 2.6 4.9 0 

Diacetyl Area Administration 5 3 (60%) <0.3 1.0 -

Diacetyl Area Breakroom 3 2 (67%) <0.8 1.4 -

Diacetyl Area Grinding 3 3 (100%) 1.6 3.3 -

Diacetyl Area Outside 3 0 (0%) <0.8 <0.9 -

Diacetyl Area Quality Control 3 2 (67%) <=0.5 1.0 -

Diacetyl Area Roasting 9 6 (67%) <=0.7 2.1 -

Diacetyl Area Storage/Holding 5 1 (20%) <=0.2 0.2 -

2,3-Pentanedione Personal Administration 1 0 (0%) <1.2 <1.2 0 

2,3-Pentanedione Personal All Over 2 1 (50%) <1.2 3.7 0 

2,3-Pentanedione Personal Delivery 1 0 (0%) <1.5 <1.5 0 

2,3-Pentanedione Personal Outside 1 0 (0%) <4.7 <4.7 0 

2,3-Pentanedione Personal Roasting 2 2 (100%) 2.2 2.8 0 

2,3-Pentanedione Personal Weigh/Package 3 3 (100%) 2.7 8.3 0 

2,3-Pentanedione Area Administration 5 0 (0%) <0.4 <1.3 -

2,3-Pentanedione Area Breakroom 3 1 (33%) <1.1 1.7 -

2,3-Pentanedione Area Grinding 3 2 (67%) <1.1 3.8 -

2,3-Pentanedione Area Outside 3 0 (0%) <1.1 <1.2 -

2,3-Pentanedione Area Quality Control 3 0 (0%) <1.1 <1.2 -

2,3-Pentanedione Area Roasting 9 3 (33%) <=0.9 1.5 -

2,3-Pentanedione Area Storage/Holding 5 0 (0%) <1.1 <1.2 -

2,3-Hexanedione Personal Administration 1 0 (0%) <2.1 <2.1 -

2,3-Hexanedione Personal All Over 2 1 (50%) <2.2 4.5 -

2,3-Hexanedione Personal Delivery 1 0 (0%) <2.7 <2.7 -

2,3-Hexanedione Personal Outside 1 0 (0%) <8.4 <8.4 -

2,3-Hexanedione Personal Roasting 2 0 (0%) <2.2 <2.8 -

2,3-Hexanedione Personal Weigh/Package 3 3 (100%) 2.7 13.2 -

2,3-Hexanedione Area Administration 5 0 (0%) <0.6 <2.3 -

2,3-Hexanedione Area Breakroom 3 0 (0%) <2.0 <2.1 -

2,3-Hexanedione Area Grinding 3 1 (33%) <2.0 4.5 -

2,3-Hexanedione Area Outside 3 0 (0%) <2.0 <2.1 -

2,3-Hexanedione Area Quality Control 3 0 (0%) <2.0 <2.1 -

2,3-Hexanedione Area Roasting 9 0 (0%) <2.0 <2.1 -

2,3-Hexanedione Area Storage/Holding 5 0 (0%) <2.0 <2.1 -

Note: NIOSH=National Institute for Occupational Safety and Health; N=number of samples; Above LOD N 

(%)=number and percentage of samples above the limit of detection (LOD); Above REL N =number above the 

NIOSH proposed recommended exposure limit (REL); ppb=parts per billion; “-“ NIOSH RELs are specified for

personal air samples and area air samples cannot be used for comparison; "All Over" location includes employees 

that were cross-trained and performed tasks at different areas; < indicates below the LOD. 

Page 44 
Health Hazard Evaluation Report 2015-0082-3287

Table A4. OSHA Methods 1013/1016 task-based personal and area air sampling results by 

location, 1st NIOSH industrial hygiene survey, July 2015. 

Analyte 

Type of 

Sample 

(area/ 

personal) 

Task Location N 

Above 

LOD N 

(%) 

Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Mean 

(minutes) 

Sample 

Duration 

(range) 

Diacetyl Personal All Over 2 0 (0%) <7.7 <9.4 17 (15-18) 

Diacetyl Personal Grinding 3 2 (67%) <=6.6 26.9 16 (15-17) 

Diacetyl Personal Roasting 6 1 (17%) <=5.8 5.8 15 (13-16) 

Diacetyl Personal Weigh/Package 9 1 (11%) <8.7 23.1 15 (11-16) 

Diacetyl Area Grinding 3 0 (0%) <8.1 <9.2 16 (15-17) 

Diacetyl Area Roasting 15 0 (0%) <3.5 <17.3 16 (8-40) 

2,3-Pentanedione Personal All Over 2 0 (0%) <6.2 <7.5 17 (15-18) 

2,3-Pentanedione Personal Grinding 3 2 (67%) <7.5 18.2 16 (15-17) 

2,3-Pentanedione Personal Roasting 6 0 (0%) <7.0 <8.6 15 (13-16) 

2,3-Pentanedione Personal Weigh/Package 9 1 (11%) <7.0 10.9 15 (11-16) 

2,3-Pentanedione Area Grinding 3 0 (0%) <6.5 <7.4 16 (15-17) 

2,3-Pentanedione Area Roasting 15 0 (0%) <2.8 <14.0 16 (8-40) 

2,3-Hexanedione Personal All Over 2 0 (0%) <6.3 <7.6 17 (15-18) 

2,3-Hexanedione Personal Grinding 3 0 (0%) <6.7 <7.6 16 (15-17) 

2,3-Hexanedione Personal Roasting 6 0 (0%) <7.1 <8.7 15 (13-16) 

2,3-Hexanedione Personal Weigh/Package 9 0 (0%) <7.1 <10.5 15 (11-16) 

2,3-Hexanedione Area Grinding 3 0 (0%) <6.6 <7.5 16 (15-17) 

2,3-Hexanedione Area Roasting 15 0 (0%) <2.8 <14.1 16 (8-40) 

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

Safety and Health; N=number of samples; Above LOD N (%)=number and percentage of samples above the 

limit of detection (LOD); < indicates below the LOD; < =indicates less than or equal to the LOD; ppb=parts 

per billion; “All Over” location includes employees that were cross-trained and performed tasks at different 

areas. 

Page 45 
Health Hazard Evaluation Report 2015-0082-3287

Table A5. OSHA Methods 1013/1016 personal task-based air sampling results, 2nd NIOSH 

industrial hygiene survey, March 2016 

Analyte Task N 

Above 

LOD N 

(%) 

Minimum 

Concentration 

(ppb) 

Maximum 

Concentration 

(ppb) 

Mean 

(minutes) 

Sample 

Duration 

(range) 

Diacetyl Cleaning Roaster 1 1 (100%) 2.4 2.4 - (7-7) 

Diacetyl Grind coffee beans 4 4 (100%) 21.9 37.6 11 (4-14) 

Diacetyl Blending roasted beans by hand 3 3 (100%) 7.5 33.4 18 (15-25) 

Diacetyl Package coffee 19 19 (100%) 3.0 34.3 15 (5-24) 

Diacetyl Roast coffee beans 9 5 (56%) <0.9 4.7 16 (15-19) 

2,3-Pentanedione Cleaning Roaster 1 0 (0%) <2.1 <2.1 - (7-7) 

2,3-Pentanedione Grind coffee beans 4 4 (100%) 8.8 20.9 11 (4-14) 

2,3-Pentanedione Blending roasted beans by hand 3 3 (100%) 5.3 22.1 18 (15-25) 

2,3-Pentanedione Package coffee 19 18 (95%) <1.0 28.4 15 (5-24) 

2,3-Pentanedione Roast coffee beans 9 7 (78%) <0.9 2.5 16 (15-19) 

2,3-Hexanedione Cleaning Roaster 1 0 (0%) <3.1 <3.1 - (7-7) 

2,3-Hexanedione Grind coffee beans 4 0 (0%) <1.5 <5.5 11 (4-14) 

2,3-Hexanedione Blending roasted beans by hand 3 0 (0%) <0.8 <1.4 18 (15-25) 

2,3-Hexanedione Package coffee 19 0 (0%) <0.9 <4.3 15 (5-24) 

2,3-Hexanedione Roast coffee beans 9 0 (0%) <1.1 <1.4 16 (15-19) 

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

and Health; N=number of samples; Above LOD N (%)=number and percentage of samples above the limit of 

detection (LOD); < indicates below the LOD; ppb=parts per billion. 

Table A6. Instantaneous* evacuated canister task-based air sampling concentration results, 2nd 

NIOSH industrial hygiene survey, March 2016. 

Task Description Diacetyl (ppb) 2,3-Pentanedione 

(ppb) 

2,3-Hexanedione 

(ppb) 

Blending roasted beans by hand #1 193 90.7 5.3 

Blending roasted beans by hand #2 24.0 23.1 1.9 

Blending roasted beans by hand #3 15.7 19.5 2.6 

Blending roasted beans by hand #4 21.3 21.9 1.5 

Grinding roasted beans (Blend #1) 64.3 51.9 1.9 

Packing roasted beans 69.7 80.5 5.5 

Pouring of roasted beans #1 4.9 2.6 <0.9 

Pouring of roasted beans #2 5.5 4.0 <0.9 

Pouring of roasted beans #3 12.8 7.9 1.7 

Pouring of roasted beans #4 9.2 8.7 <0.9 

Pouring of roasted beans #5 10.4 6.6 1.0 

Pouring of roasted beans #6 13.1 10.7 2.3 

Pouring of roasted beans #7 15.7 8.8 <0.9 

Pouring of roasted beans #8 44.6 21.2 2.9 

Note: NIOSH=National Institute for Occupational Safety and Health; ppb=parts per billion; < indicates 

below the limit of detection.
 

*Sampling duration approximately 30 seconds; task-based air samples were collected by placing the inlet of the 

canister sampler in the employee’s personal breathing zone as he/she performed work task to mimic exposure.
 

Page 46 
Health Hazard Evaluation Report 2015-0082-3287

Table A7. Instantaneous evacuated canister source air sampling results* for diacetyl, 

2,3-pentanedione and 2,3-hexanedione, 1st NIOSH industrial hygiene survey, July 2015. 

Source Diacetyl 

(ppb) 

2,3-Pentanedione 

(ppb) 

2,3-Hexanedione 

(ppb) 

After grinding 14 pounds in 19 minutes 146 113 8.0 

After grinding 14 pounds in 19 minutes 521 229 24.0 

Inside roasted bean storage bin #1 3248 2064 173 

Inside roasted bean storage bin #2 99.4 127 6.5 

Inside roasted bean storage bin #3 1725 814 16.7 

Inside roasted bean storage bin #4 563 576 17.3 

Inside roasted bean storage bin #5 454 461 17.4 

Inside roasted bean storage bin #6 120 98.0 5.1 

Inside roasted bean storage bin #7 4911 1774 161 

Inside roasted bean storage bin #8 2038 820 124 

Inside roasted bean storage bin #9 940 252 26.0 

Inside roasted bean storage bin #10 310 182 7.5 

Inside roasted bean storage bin #11 2380 1277 26.4 

Inside roasted bean storage bin #12 1122 632 35.8 

Inside roasted bean storage bin #13 125 50.0 13.0 

Inside roasted bean storage bin #14 920 432 14.0 

Inside roasted bean storage bin #15 669 380 13.4 

Inside roasted bean storage bin #16 7011 4419 156 

Inside roasted bean storage bin #17 2392 1424 219 

Inside roasted bean storage bin #18 997 607 96.2 

Inside roasted bean storage bin #19 1931 773 91.3 

Inside roasted bean storage bin #20 991 1195 50.6 

Inside roasted bean storage bin #21 2744 3216 108 

Inside roasted bean storage bin #22 986 412 33.0 

Inside roasted bean storage bin #23 229 84.0 8.8 

Inside roasted bean storage bin #24 119 47.0 5.0 

Inside roasted bean storage bin #25 304 235 5.0 

Inside roasted bean storage bin #26 580 607 12.0 

Inside roasted bean storage bin #27 1119 678 18.0 

Inside roasted bean storage bin #28 427 235 5.0 

Inside roasted bean storage bin #29 431 472 18.6 

Inside roasted bean storage bin #30 987 881 32.0 

Roasting #1 <0.3 <0.4 <0.6 

Roasting #2 87.1 44.5 5.9 

Roasting #3 8.9 7.7 7.2 

Roasting #4 109 45.7 6.8 

Note: NIOSH = National Institute for Occupational Safety and Health; ppb=parts per billion; 

< =indicates below the limit of detection. 

*The roasted coffee beans in the bins off-gassing for different amounts of time, and this could be 

responsible for some of the differences in headspace analysis results. 

Page 47 
Health Hazard Evaluation Report 2015-0082-3287

Table A8. Instantaneous evacuated canister source air sampling results for diacetyl, 

2,3-pentanedione and 2,3-hexanedione, 2nd NIOSH industrial hygiene survey, March 2016. 

Source Description Diacetyl 

(ppb) 

2,3-Pentanedione 

(ppb) 

2,3-Hexanedione 

(ppb) 

Freshly roasted beans at conduction roaster door to cooling drum #1 

Freshly roasted beans at conduction roaster door to cooling drum #2 

Freshly roasted beans at convection roaster door to cooling bin 

Freshly roasted beans at lip of open transfer container #1 

Freshly roasted beans at lip of open transfer container #2 

Freshly roasted beans at lip of open transfer container #3 

Freshly roasted beans at lip of open transfer container #4 

Roasted beans at lip of open transfer container 

Roasted beans at lip of open transfer container 

Grinding 16 ounce roasted bean blend 

Grinding blend #1 

Grinding blend #2 

Grinding blend #2 

Grinding blend #2 

Transfer of roasted beans from convection roaster cooling bin to bucket 

Transfer of roasted beans from storage bin into bucket 

Transfer of roasted beans from conduction roaster cooling bin to bucket 

Transfer of roasted beans 

Transfer of roasted beans for blending 

Transfer of roasted beans from convection roaster cooling bin to container 

9.3 

6.0 

4.2 

12.9 

12.8 

0.5 

11.6 

30.5 

17.2 

158 

359 

127 

364 

520 

10.9 

12.7 

23.7 

56.2 

184 

3.4 

3.0 

3.3 

3.3 

6.7 

4.8 

0.6 

7.6 

18.6 

9.7 

124 

309 

127 

439 

462 

6.3 

12.2 

17.5 

48.1 

98.1 

1.1 

<1.0 

<1.0 

<0.9 

1.6 

<1.0 

0.8 

1.2 

1.5 

2.8 

2.8 

35.6 

2.9 

11.3 

13.7 

<0.9 

<0.9 

1.3 

5.8 

12.0 

<1.0 

Note: NIOSH=National Institute for Occupational Safety and Health; ppb=parts per billion; < indicates below the 

limit of detection. 

Table A9. Instantaneous evacuated canister pre-and-post shift background air sampling results, 

2nd NIOSH industrial hygiene, March 2016. 

Analyte Sample Type Sample Location Pre- or Post- shift Concentration 

(ppb) 

Diacetyl Background Storage/Holding Pre-shift 3.5 

Diacetyl Background Storage/Holding Post-shift 15.5 

2,3-Pentanedione Background Storage/Holding Pre-shift 1.6 

2,3-Pentanedione Background Storage/Holding Post-shift 8.5 

2,3-Hexanedione Background Storage/Holding Pre-shift <0.6 

2,3-Hexanedione Background Storage/Holding Post-shift <0.6 

Note: NIOSH = National Institute for Occupational Safety and Health; ppb=parts per billion; < indicates below the 

limit of detection. 

Page 48 
Health Hazard Evaluation Report 2015-0082-3287

Table A10. Bulk coffee sample results using headspace analysis from both NIOSH 

industrial hygiene surveys, July 2015 and March 2016. 

Survey Bulk Sample Description Diacetyl 

(ppb) 

2,3-Pentanedione 

(ppb) 

2,3-Hexanedione 

(ppb) 

First Green bean #1 <170 <203 <275 

First Green bean #2 <171 <204 <277 

First Whole roasted bean #1 <169 189 <273 

First Whole roasted bean #2 606 705 302 

First Whole roasted bean #3 600 781 <275 

First Whole roasted bean #4 434 311 <280 

First Whole roasted bean #5 <171 171 <276 

First Whole roasted bean #6 167 <204 338 

First Whole roasted bean #7 526 1069 648 

First Whole roasted bean #8 308 161 <275 

First Whole roasted bean #9 787 1172 <277 

First Whole roasted bean #10 497 875 <276 

First Ground roasted bean #1 <171 <204 <276 

First Ground roasted bean #2 297 175 <277 

First Ground roasted bean #3 <171 <204 <277 

Second Green bean #3 <84 <117 <208 

Second Fresh whole roasted bean #10 2,012 1,042 <208 

Second Whole roasted bean #10 2,069 1,350 <208 

Second Whole roasted bean #11 1,172 207 <207 

Second Whole roasted bean #12 1,324 1,314 <207 

Second Whole roasted bean #13 1,083 1,258 <207 

Second Whole roasted bean #14 1,558 907 <206 

Note: NIOSH = National Institute for Occupational Safety and Health; ppb=parts per billion; < indicates 

below the limit of detection; detection limits improved from first to second visit. 

Page 49 
Health Hazard Evaluation Report 2015-0082-3287

Table A11. Real-time air monitoring for carbon dioxide, carbon monoxide, temperature, 

and relative humidity, 1st NIOSH industrial hygiene survey, July 2015. 

Location CO2 (ppm) CO (ppm) Temp (°F) RH (%) 

Outside facility 

Break room 

Shipping and receiving 

Roaster machine 

Auto-weigh machine 

Storage/Holding 

Administrative office 

Customer service office 

Quality control room 

Roasted bean storage bin #1 * 

Roasted bean storage bin #2* 

Roasted bean storage bin #3* 

Roasted bean storage bin #4* 

Roasted bean storage bin #5* † 

Roaster machine† 

Roasted bean storage bin #6* † 

Roasted bean storage bin #7*† 

Roasted bean storage bin #8*† 

Roasted bean storage bin #8*† 

Roasted bean storage bin #9*† 

Roasted bean storage bin #10*† 

Roasted bean storage bin #11*† 

Roasted bean storage area† 

Green bean storage area† 

430 

571 

820 

800 

490 

600 

790 

660 

610 

5,200 

5,200 

2,400 

1,500 

4,200 

476 

900 

750 

950 

860 

1,850 

1,100 

2,300 

670 

540 

<0.1 

0.7 

1.1 

1.6 

0.9 

0.5 

0.9 

1 

0.7 

386 

130 

410 

160 

-

-

-

-

-

-

-

-

-

-

-

75 

74 

79 

80 

-

79 

78 

78 

77 

77 

78 

83 

84 

83 

78 

76 

76 

76 

76 

77 

78 

78 

77 

76 

71 

-

68 

66 

-

65 

59 

59 

55 

35 

29 

26 

33 

32 

42 

45 

48 

45 

47 

47 

43 

43 

48 

49 

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

=carbon dioxide; CO=carbon 

monoxide; ppm=parts per million; °F=degrees Fahrenheit; < indicates below the limit of detection; 

“-“indicates that the measurement was not recorded. 

*Probe was placed directly inside roasted coffee bean storage bin with cover on bin. 

†CO probe sensor did not provide a reading. 

Page 50 
Health Hazard Evaluation Report 2015-0082-3287

Table A12. Real-time air monitoring for carbon dioxide, carbon monoxide, temperature, 

and relative humidity, 2nd NIOSH industrial hygiene survey, March 2016. 

Area sample location Measurement Minimum Maximum Average 

Roaster machine (1) CO2 (ppm) 289 3,612 502.8 

Roaster machine (1) CO (ppm) <0.1 7.8 0.8 

Roaster machine (1) Temperature (°F) 71 112.7 91.7 

Roaster machine (1) Relative Humidity (%) 11.6 52.2 25.4 

Roaster machine (2) CO2 (ppm) 334 746 463 

Roaster machine (2) CO (ppm) <0.1 4.5 0.3 

Roaster machine (2) Temperature (°F) 68.3 85 77.6 

Roaster machine (2) Relative Humidity (%) 18.9 35.2 23.8 

Roasted bean storage area CO2 (ppm) 438 2,246 599 

Roasted bean storage area CO (ppm) 0.6 21.3 2.4 

Roasted bean storage area Temperature (°F) 66.6 68 67.1 

Roasted bean storage area Relative Humidity (%) 23.4 39.8 27.3 

Note: NIOSH = National Institute for Occupational Safety and Health; ppm=parts per million; 

CO=carbon monoxide; CO2

=carbon dioxide; °F =degrees Fahrenheit; < indicates below the limit of 

detection. 

Table A13. Area air sampling results for inhalable and respirable dust, 1st NIOSH 

industrial hygiene survey, July 2015. 

Dust Location N % Above 

LOD 

Minimum 

Concentration 

(mg/m3) 

Maximum 

Concentration 

(mg/m3) 

Inhalable Administration 2 100 0.051 0.117 

Inhalable Grinding 1 100 0.1 0.1 

Inhalable Outside 1 100 0.069 0.069 

Inhalable Quality Control 1 100 0.069 0.069 

Inhalable Roasting 3 100 0.099 0.139 

Inhalable Storage/Holding 2 100 0.068 0.075 

Respirable Administration 2 0 <0.006 <0.009 

Respirable Breakroom 1 0 <0.006 <0.006 

Respirable Grinding 1 100 0.008 0.008 

Respirable Outside 1 100 0.008 0.008 

Respirable Quality Control 1 0 <0.006 <0.006 

Respirable Roasting 3 100 0.012 0.016 

Respirable Storage/Holding 2 100 0.01 0.012 

Note: NIOSH = National Institute for Occupational Safety and Health; N=number of samples; mg/ 

m3

=milligram per cubic meter; % Above LOD=percentage of samples above limit of detection (LOD) for

the instrument used to detect inhalable or respirable dust; < indicates below the limit of detection for the 

instrument used to detect respirable dust. 

Page 51 
Health Hazard Evaluation Report 2015-0082-3287

 

 

 

 

Table A14. Prevalence of reported symptoms, NIOSH medical survey, March 2016 

Symptom 

Experienced in the last 12 months 

N = 16 

Number (%) 

Experienced in the last 4 weeks 

N = 16 

Number (%) 

Nose symptoms* 13 (81%) 9 (56%) 

Eye symptoms† 8 (50%) 2 (13%) 

Sinusitis or sinus problems 7 (44%) 5 (31%) 

Problem with ability to smell 6 (46%) -

Phlegm on most days for 3 months 3 (19%) -

Lower respiratory symptoms (reported at least 

one of the following) 10 (63%) 6 (38%)

 Chest wheezing or whistling 9 (56%) 5 (31%)

 SOB on level ground or walking up a slight a hill 4 (25%) -

Breathing trouble 2 (13%) 2 (13%) 

Awoke with chest tightness 2 (13%) 0 

Awoke with shortness of breath 1 (6%) 0

 Usual cough 1 (6%) 1 (6%) 

Asthma attack 1 (6%) 0 

Systemic symptoms (reported at least one of the 

following) 11 (69%) 6 (38%)

 Flu-like achiness or achy joints 9 (56%) 4 (25%)

 Fever or chills 8 (50%) 4 (25%)

 Unusual tiredness or fatigue 5 (31%) 3 (19%) 

Note: NIOSH = National Institute for Occupational Safety and Health; N=number of participants; SOB=shortness of 

breath; “-“= A four week question was not asked for the symptom. 

*Nose symptoms includes one or both of the following: 1) stuffy, itchy, or runny nose or 2) stinging, burning nose.

†Eye symptoms includes one or both of the following: 1) watery, itchy eyes or 2) stinging, burning eyes. 

Page 52 
Health Hazard Evaluation Report 2015-0082-3287

Table A15. Adjusted* comparisons of symptoms and self-reported physician diagnosis among 

NIOSH medical survey participants (N=16) to U.S. adult population, March 2016 

Health condition Comparative 

population† 

Observed 

Number 

Expected 

Number 

SMR 

(95% CI)‡ 

Watery, itchy eyes last 12 months NHANES III 7 5.9 1.2 (0.6–2.5) 

Stuffy, itchy, or runny nose last 12 months NHANES III 12 8.6 1.4 (0.8–2.4) 

Sinus problems last 12 months NHANES III 6 5.4 1.1 (0.5–2.4) 

Phlegm 3 consecutive month or more NHANES III 3 1.2 2.5 (0.9– 7.5) 

Wheeze last 12 months NHANES 2007-2012 9 2.0 4.5 (2.4–8.6) 

Shortness of breath on exertion NHANES III 4 2.6 1.6 (0.6–4.0) 

Cough 3 consecutive months or more NHANES III 1 1.1 0.9 (0.2–5.0) 

Chronic bronchitis (physician-diagnosed) NHANES III 0 0.71 0 (0–5.4) 

Ever asthma (physician-diagnosed) NHANES 2007-2012 2 2.3 0.9 (0.2 –3.2) 

Current asthma (physician-diagnosed) NHANES 2007-2012 2 1.1 1.8 (0.5– 6.7) 

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

Page 53 
Page 54 Health Hazard Evaluation Report 2015-0082-3287

Appendix B: Figures
 

Figure B1. Roaster exhaust stack plugged with chaff residue and debris, NIOSH ventilation 

assessment, July 2015. 
Health Hazard Evaluation Report 2015-0082-3287 Page 55 

Figure B2. Other roaster exhaust stack plugged with chaff residue and debris, NIOSH 

ventilation assessment, July 2015. 
Page 56 Health Hazard Evaluation Report 2015-0082-3287

This page left intentionally blank 
Health Hazard Evaluation Report 2015-0082-3287 Page 57 

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

2,3-hexanedione, coffee, carbon monoxide, carbon dioxide, volatile organic compounds 

(VOCs). 
Page 58 Health Hazard Evaluation Report 2015-0082-3287

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

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

(6)). The Health Hazard Evaluation Program also provides, upon request, technical assistance 

to federal, state, and local agencies to investigate occupational health hazards and to prevent 

occupational disease or injury. Regulations guiding the Program can be found in Title 42, 

Code of Federal Regulations, Part 85; Requests for Health Hazard Evaluations (42 CPR Part 

85). 

Disclaimer 

The recommendations in this report are made on the basis of the findings at the workplace 

evaluated and may not be applicable to other workplaces. 

Mention of any company or product in this report does not constitute endorsement by the 

National Institute for Occupational Safety and Health (NIOSH). 

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

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

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

of the publication date. 

Acknowledgments 

Desktop Publisher: Tia McClelland 

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

Laboratory Support: Dru Burns, Kyle Hatcher, Ryan LeBouf, Anand Ranpara 

Site Visit Team Members: Rachel Bailey, Reid Harvey, Alyson Johnson, Ryan LeBouf, 

Christopher Mugford, Stephen Martin, Jr., Marcia Stanton, Brian Tift 

Availability of Report 

Copies of this report have been sent to the employer and employees at the 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/2015-0082-3287.pdf. 

All other Health Hazard Evaluation 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 exposure and respiratory 

health at a coffee processing facility. By LeBouf RF, Martin SB, Mugford C, Stanton

ML, 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. 2015-0082-3287. 
Delivering on the Nation’s promise:

Safety and health at work for all people through research and prevention 

To receive documents or other information about 

occupational safety and health topics, contact NIOSH 

Telephone: 1-800-CDC-INFO (1-800-232-4636) 

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or visit the NIOSH website at http://www.cdc.gov/niosh