At Stone Creek Coffee, a pillar of our company is to Never Stop Learning. Let’s face it: as we grow older, it’s not always easy to change. When you’re used to doing things a particular way and you’re faced with learning, it’s not easy to accept new knowledge and to grow from it. After all, as the saying goes, “If it ain’t broke, don’t fix it.” So by that token, why not be stubborn and refuse to seek change? However, success is not born out of choosing to be stagnant or refusing to grow, but rather out of our humbly seeking to grow beyond that which we have already attained. In the past few years, humbly seeking to grow is precisely what Stone Creek Coffee has done in the face of new knowledge about workplace safety.
In 2015 and 2016, major media news sources began to pick up stories about the potential danger of a byproduct of coffee roasting called diacetyl (also known as 2,3-butanedione). Before this time, this potential danger was, by and large, unknown in the coffee industry and little information was shared about it by regulatory bodies that govern such workplace safety. By the time 2017 rolled around, and largely thanks to the media, this potential workplace danger was becoming more well known, and an issue that Stone Creek Coffee wanted to meet head on.
Rather than being behind the times, Stone Creek Coffee wanted to get ahead of them. At the time, we were unsure of what kind of can of worms we were opening, but diligently sought to learn all that we could and create a plan to move forward from it. In this article, we share our concerns about diacetyl in the workplace and disseminate what Stone Creek Coffee has done to protect its employees from its exposure, and how our commitment to Never Stop Learning has driven us as a company and called us to be better.
Diacetyl (2,3-butanedione) and 2,3-pentanedione
Over ten years ago, and long before it was on the radar of the coffee industry, the potential dangers of diacetyl exposure were shared all over the media when it became known that not only was diacetyl used in microwave popcorn to give it a buttery flavor, but dangerously so. In fact, the medical term ‘popcorn lung’ (known medically as bronchiolitis obliterans) is a direct result of the inquiry into the potential dangers of long-term exposure to the chemical at popcorn facilities. Since this initial inquiry, the scientific community, as well as our communities at large, have become more knowledgeable about diacetyl and its potential for harm.
What is diacetyl? A brief history and overview
The medical definition of diacetyl is, “a greenish yellow liquid compound (CH3CO)2 that has an odor like that of quinone, that is chiefly responsible for the odor of butter and contributes to the aroma of coffee and tobacco, and that is used as a flavoring agent in foods (as margarine)”.
Both interestingly and oddly enough, to this day if you search for the (non-medical) definition of ‘diacetyl’ on the internet, the search results by and large deal solely with the chemical additive, rather than the naturally occurring chemical compound that it is meant to mimic. In fact, OSHA’s (Occupational Safety and Health Administration) website definition simply reads, “Diacetyl (also called 2,3-butanedione) is a chemical that has been used to give butter-like and other flavors to food products, including popcorn.” There is no mention that diacetyl is a natural byproduct of fermentation, or that it is released by the process of roasting coffee. When this is mentioned, it is by news media sources acting as consumer watchdogs.
How and why is diacetyl potentially dangerous?
As was gleaned from the research into using diacetyl as a flavor additive from over a decade ago, diacetyl is unequivocally recognized as a potentially hazardous chemical when ingested. Diacetyl exposure is of particular concern for the respiratory health of those who are regularly exposed to it over long periods of time (i.e. factory workers who regularly come in contact with it). In fact, according to OSHA, severe respiratory tract injury has been observed in animals after “an acute inhalation exposure to butter flavorings. Severe respiratory tract injury, similar to that observed with butter flavoring vapors exposure, was also observed following acute inhalation exposures of rats to diacetyl or 2,3-pentanedione and repeated inhalation exposures of mice to diacetyl and rats and mice to 2,3-pentanedione.”
Further, NIOSH (National Institute for Occupational Safety and Health) has concluded that investigations of employees who suffer with obliterative bronchiolitis (aka ‘popcorn lung’) from diacetyl exposure in the workplace substantiate the claim that there is a causal relationship “between diacetyl exposure and the development of this disease”, and, moreover, “that an exposure is the likely cause of specific health effects.” Bronchiolitis obliterans is “a severe narrowing or complete obstruction of the small airways”. Additionally, NIOSH has expressed concern about 2,3-pentanedione, a chemical similar to diacetyl based on its structural similarities to it, and animal studies showing that it, too, “caused damage in the airways of animals, similar to that caused by diacetyl.”
How do you protect yourself and others from diacetyl exposure?
Luckily for us, we live in the twenty-first century, which is rife with rules and regulations that are meant to keep workers safe–and rightfully so. Both OSHA and NIOSH are government organizations that help oversee occupational safety in the United States of America and whose job is to protect workers from undue, hazardous exposures. OSHA is an agency of the United States Department of Labor, whose responsibility is to ensure safety at work and a healthful work environment for employees in the United States of America. NIOSH is a government agency responsible for conducting research and making recommendations for prevention of work-related illness and injury, whose parent agency is the CDC (Center for Disease Control). Although OSHA does not yet have a legal, regulated requirement for diacetyl exposure limits in place, they share NIOSH’s safety recommendations for ‘acceptable’ exposure levels, which should act as a guide for companies who encounter diacetyl exposure in the workplace. These exposure limits are no more than 5 ppb (parts per billion) in a 8-10 hour time frame, or no more than 25 ppb in a 15 minute time frame, on average, for diacetyl, and no more than 9 ppb in an 8-10 hour time frame for 2,3-pentanedione.
NIOSH itself is an invaluable resource for evaluating the amount of diacetyl exposure in a given workspace. NIOSH works with companies to conduct research and assess the occupational safety of a given workspace where there is exposure or exposure to potentially dangerous chemicals. Not only do they access the overall exposure rates of a workspace over a period of multiple days, providing both initial checks and follow-up checks free of charge, but they also check the health of the employees that work in it, ensuring that workers are in good enough health to continue to work somewhere that they face exposure.
The coffee industry, as well as other industries, can use the safety recommendations of NIOSH as guidelines when creating a plan for achieving workplace safety. If a company is not complying with the guidelines, they must reassess their situation and resolve to find a solution that puts them under the exposure limits. It is essential for worker safety that these exposure limits are not exceeded.
Fortunately for many food manufacturing employers, there are immediate, relatively affordable measures they can take to protect their employees from diacetyl and 2,3-pentanedione exposure. One said measure is to have workers wear a NIOSH-approved “full-face air-purifying respirator with organic vapor cartridges and particulate filters”. This filters the air that workers breathe in and out if they work in an area that exposes them to diacetyl and 2,3-pentanedione. Additionally, employees who are exposed to these chemicals should change their clothes immediately after work to remove any residual chemicals left on their clothing from their body.
On top of changing clothes, keeping proper hygiene is also essential to the health of workers. Workers should regularly wash their hands throughout the day, especially when switching between tasks, and at the end of a shift to avoid transference of chemicals. Another, more invested, way to achieve workplace safety is to set up and regularly test the performance of an HVAC (heating, ventilation, and air conditioning) system in a given space. A properly managed HVAC system helps ventilate the air surrounding workers who are exposed to diacetyl and 2,3-pentanedione, and is able to achieve air quality optimization that puts it below the specified NIOSH exposure limits. When handling the liquid form of diacetyl, it is also recommended to wear chemical safety goggles and chemical resistant gloves.
Stone Creek Coffee: A case study in workplace safety
To further investigate ways to mitigate diacetyl exposure, this article uses Stone Creek Coffee and the updates the company has made as an example of how to properly protect workers from it. Stone Creek Coffee is located in Milwaukee, WI and was founded in 1993 by Eric Resch. Back in 1993, diacetyl was not yet a concern for the coffee industry. In fact, it wasn’t until over a decade later that problems with diacetyl became evident in the production of microwave popcorn, and over two decades later that the coffee industry caught on. However, a core principle of the company is to Never Stop Learning, and as soon as Stone Creek became aware of the potential dangers of diacetyl exposure, we were determined to learn more and take action in the face of new knowledge.
2016 & 2017
As soon as Stone Creek became aware of the potential danger, we began offering NIOSH-approved respirators to all production employees on an opt-in basis in 2016. Then, in February of 2017, Stone Creek enlisted the help of NIOSH to test the air quality and the health of their production workers. NIOSH tested the roasting facilities of Stone Creek Coffee for one week, collecting data that would glean insights into how much exposure employees were facing during this time. They collected samples from a broad array of areas throughout the facility, ranging from the Cupping Lab where coffee samples are roasted, to the production area where coffee is roasted and ground for production. When employees were tested to gauge their overall health, several tests were performed on them, including a spirometry test, which measures lung function and capacity.
Several months after the initial tests, Stone Creek was sent a general set of data that excluded names of employees, while individual employees were sent and received the results from their personal testing. Of the 15 areas where samples were gathered, 12 had higher than recommended exposure rates to diacetyl (recommendation is no more than 5 ppb), and 10 had higher than recommended exposure rates to 2,3-pentanedione (recommendation is no more than 9 ppb). Faced with these results, Stone Creek decided to pursue HVAC as our primary means of protecting workers from the potential dangers.
In the summer of 2018, Stone Creek worked with an engineer from the Sigma Group and technicians from Pure Mechanical on HVAC installation in order to further mitigate the potential threat of diacetyl exposure. By installing the appropriate ventilation and dampers in the facility, in conjunction with the afterburner which was already present in the facility, we were able to achieve more optimal air quality. Before definitively drawing this conclusion, we enlisted the help of NIOSH once again to come and re-test the air.
After the 2018 HVAC installation, in February 2019 NIOSH returned to Stone Creek Coffee. They tested the facilities once more to definitively conclude whether or not the HVAC installation was successful in its goal to protect employees from diacetyl exposure. NIOSH collected 57 area air samples in 19 locations throughout Stone Creek’s facility. Sampling locations were the same as they were in January 2017 (n=15) with the addition of four locations (behind small grinders, below large grinder, behind roasted bean destoner/hopper, and packaging area to right of grinders).
2017 vs 2019 results
In 2017, the average diacetyl concentration across all samples was 16.8 parts per billion (ppb) and the average 2,3-pentanedione concentration across all samples was 12.4 ppb. When the facilities were re-tested in 2019, the average diacetyl concentration across all samples was 4.0 ppb and the average 2,3-pentanedione concentration across all samples was 3.6 ppb.
NIOSH recommend no more than 5 ppb over a 40 hour work week over a 40 year work career on diacetyl and not more than 9 ppb over a 40 hour work week over a 40 year work career on 2,3-pentanedione. When the air was re-tested at Stone Creek in 2019, both the average diacetyl and 2,3-pentanedione concentrations were below these recommended exposure limits. With these results in hand, Stone Creek can confidently say that our work on our HVAC system proved successful in improving their air quality and workplace safety. The additional availability of respirators further protects employees from exposure as well.
Abigail Adams once said, “Learning is not attained by chance, it must be sought for with ardor and diligence.” Learning, after all, is not something that we just happen upon, but something that we humbly seek with a passion to grow beyond the knowledge we have already attained. It isn’t easy, and in many ways, is one of the most challenging things that we encounter in our day to day lives; and yet, with growing pains comes growth.
Over the past couple of years, we’ve done a lot of learning and growing at Stone Creek Coffee, and while that learning wasn’t always easy, and sometimes even painful, from it, we grew and are better for it. We are grateful for our learning, and look forward to a future filled with even more learning yet to come. We are continually arriving at and departing from our learning, and although that doesn’t always make the ground steady for footing, we wouldn’t have it any other way. We continue to trek ahead on our pursuit to Never Stop Learning, and invite you to do the same.