NIOSH: Coffee Workers May Be at Risk for Lung Disease
Recent NIOSH research indicates that workers at coffee processing facilities may be at risk for lung disease caused by occupational exposure to diacetyl and 2,3-pentanedione, volatile organic compounds that are naturally produced and released when coffee beans are roasted and when coffee is ground. Diacetyl and 2,3-pentanedione are also produced by chemical manufacturers to be used as ingredients in flavorings for some food products such as microwave popcorn, bakery mixes, and flavored coffee. The lung disease
obliterative bronchiolitis, previously identified in workers in the flavoring manufacturing and microwave popcorn industries, was recently diagnosed in five employees who had worked at a coffee processing facility that roasted, ground, and flavored coffee. NIOSH found elevated levels of diacetyl and 2,3-pentanedione in the air of the facility, and current employees reported respiratory symptoms consistent with undiagnosed lung disease.
The lung disease
obliterative bronchiolitiswas recently diagnosed in five employees who had worked at a coffee processing facility that roasted, ground, and flavored coffee.
“When we looked at the mean 2,3-pentanedione and diacetyl personal air samples by job title, we found the concentrations were highest for employees in the flavoring room and unflavored grinding packaging room,” says Rachel L. Bailey, DO, MPH, a medical officer in the NIOSH Respiratory Health Division. Among the workers who had high exposures were the mixers, flavoring specialists, packers, and the operators of grinding and packaging machines, Bailey says. NIOSH has 11 ongoing health hazard evaluations of coffee processing facilities. Bailey notes that NIOSH staff will collect both area and personal air samples, and perform task-based air sampling during roasting, grinding, and other tasks. Workers at these facilities will also complete health questionnaires to determine whether they are experiencing respiratory symptoms. NIOSH will also administer breathing tests to assess lung function. “Many workplace interventions that we’ve recommended in the flavoring industry and the microwave popcorn industry, such as isolation, using local exhaust, general ventilation, and respiratory protection, might be useful in the coffee processing industry,” Bailey says. In July, NIOSH released
guidanceto reduce workers’ exposures to diacetyl and 2,3-pentanedione. The agency has also developed a
Web pagefor coffee processing facilities that includes interim recommendations, including air sampling to detect and measure potential concentrations of the chemicals. NIOSH has proposed a recommended exposure limit (REL) of 5 ppb for diacetyl and 9.3 ppb for 2,3-pentanedione as a time-weighted average (TWA) for up to 8 hours per day during a 40-hour workweek. For comparison, ACGIH’s threshold limit value (TLV) for diacetyl is two times higher than the proposed REL: 0.01 ppm TWA, or 10 ppb TWA. Because the proposed RELs are so low, NIOSH is interested in identifying and using sensors or technologies that can capture these low levels to help researchers understand peak exposures, says AIHA member Ryan F. LeBouf, PhD, CIH, a research industrial hygienist in the NIOSH Respiratory Health Division. “It’s also important to look at other techniques for sampling flavorings,” LeBouf says. “One thing we’ve been doing is using evacuated canisters to sample whole air. Instead of using a sorbent and drawing air across the sorbent, you just collect your air into a canister and take it back to the lab and analyze it. It’s a lot easier in the field, and all the onus of analysis is on the laboratory staff.” LeBouf is working on a draft method for the canisters to be published in the NIOSH
Manual of Analytical Methods.
Special to the Digital Synergist: An Interview with Rachel Bailey and Ryan LeBoufRachel Bailey and Ryan LeBouf of NIOSH recently spoke with The Synergist about the agency’s ongoing investigations of exposures to flavoring chemicals in coffee processing facilities. The following transcript has been edited for clarity. The Synergist: What can the coffee processing industry learn from the popcorn industry about controlling occupational exposure to flavoring chemicals? Rachel Bailey: The popcorn and flavoring industries have implemented engineering controls to reduce exposure and the risk of obliterative bronchiolitis in their workers. Many of these processes used in the flavoring/food manufacturing industries are similar, and so they can be utilized other places. For example, small-scale weighing and handling of ingredients are common tasks used in flavoring and food production, and these tasks of weighing ingredients can lead to workers exposure through scooping and pouring and dumping. The use of slotted backdraft ventilation might be useful in the coffee processing facilities. Another task is dumping or emptying things: a worker will cut open a bag of material and dump the ingredients into a hopper. A ventilated dump-bag station—a hopper outfitted with an exhaust ventilation system that pulls dust away from the worker—[is a possible control]. So there are lots of engineering controls that have been utilized in both the microwave popcorn and the flavoring industry that—depending on what we find in the coffee processing facilities—might be utilized there. A lot of the workplace interventions such as isolation, using local exhaust, general ventilation, respiratory protection—those types of things that we’ve recommended in the flavoring industry and the microwave popcorn industry might be useful in the coffee processing industry. TS: What do you most hope to learn from the ongoing health hazard evaluations at coffee processing facilities this year? RB: We have 11 ongoing health hazard evaluations in coffee processing facilities, and so we hope to learn if workers are at risk for exposure to diacetyl and 2,3-pentanedione, and we plan to collect air samples in the workplace to measure the concentrations of these two chemicals. We’ll collect both area and personal air samples and conduct task-based air sampling during roasting, grinding, opening storage bins or containers with roasted coffee beans, and pouring or adding flavoring. And we’re also going to administer health questionnaires to determine if workers are having any type of respiratory symptoms, and then we’re going to administer breathing tests to assess their lung function. We’re using the OSHA methods for collection of air samples, but we also have some other methods we’re using. Ryan LeBouf: The traditional method to collect these chemicals is an OSHA method—OSHA method 1013, 1016, and 1012. And they all use a silica gel tube. What we’ve done here is used an alternate detector, a mass spectrometer, which increases sensitivity, and also provides selectivity. The traditional detectors, like a flame ionization detector for the 1013 and1016 methods, are non-selective. With the mass spectrometer you get a whole extra layer of information, which is the mass spectrum of the chemical, so you can identify it as well as quantify it. Using this alternate detector for mass spectrometry, we’ve been able to achieve much, much lower detection limits on the order of the more sensitive 1012 technique. It’s not necessarily new—OSHA developed these methods initially with the flame ionization detector, and they started looking at mass spectrometry at the same time as us. TS: In what other industries or types of facilities might occupational exposure to diacetyl and 2,3-pentanedione be a concern? RB: Flavorings are added to a number of food products, including bakery products like cake mixes, flour, margarine, dairy products such as cheese and yogurt, snack foods such as cookies, or spreads like cream cheese, or chips or crackers. It’s also in some beverages as well as candy, ice cream, and frozen food. Right now all our ongoing health hazard evaluations regarding flavorings are in coffee processing facilities. Diacetyl also occurs naturally in beer, butter, vinegar, and other food products. And then there’s starter distillate: it’s basically cultured with skim milk and lactic acids, and it often contains diacetyl. Often this is added as an ingredient into food products. TS: CDC’s Morbidity and Mortality Weekly Report mentioned that cases of obliterative bronchiolitis are potentially underreported. What do you perceive is the level of awareness among physicians of this lung disease’s association with occupational exposure to flavoring chemicals? RB: Because this is an uncommon disease, often physicians will diagnose workers with the more common diseases like asthma, COPD, or bronchitis. It’s important that physicians and healthcare providers ask about their patients’ occupational history. If a physician asks about the work history and tasks, then they have a better chance of making the link with this disease. It’s hard to say the level of awareness in physicians. Certainly information about flavoring-related lung disease has been published for a number of years in medical journals as well as presented at medical conferences. And NIOSH also has a flavoring website and, a few years back, developed an informational pamphlet about flavoring-related lung disease that was sent out to a number of physicians. Regarding exposures to natural diacetyl in the coffee processing industry, we have a Web page that we’ve developed in the past few months about this, and there have also been a number of articles in the general papers that have gotten the word out. But again, I’d say because it’s a rare disease, workers are misdiagnosed initially, and one big link is asking about the person’s work history. And if you hear that they’ve worked with flavorings, then it’s easier to make that leap to this particular disease. TS: Does NIOSH have any recommendations related to exposures to diacetyl substitutes? RB: The one substitute that we’re seeing more and more is 2,3-pentanedione. Diacetyl’s a 4-carbon alpha-diketone and 2,3-pentanedione is a 5-carbon alpha-diketone, but they’re very similar in their toxicity when animal studies have been done. Basically, diacetyl substitutes should not be assumed safe until toxicological studies are performed. Two other chemicals we’ve seen are 2,3-hexanedione and 2,3-heptanedione. There are no toxicological studies that I’m aware of for those two substitutes. So you have to be very careful when using those substitutes unless there’s toxicological data, and there’s very sparse toxicological data for these substitutes—except for 2,3-pentanedione, and that data shows us that it’s just as toxic as diacetyl. TS: Are you able to speak to any future plans for NIOSH research on flavorings-related lung disease? RL: In addition to the current health hazard evaluations, we’re interested in other areas where flavorings are used, and one of those is electronic cigarettes. In order to make all these flavored e-juices, they use a lot of flavorings. RB: At the initial microwave popcorn plant that NIOSH evaluated from 2000 to 2003, NIOSH did eight medical surveys. We have gone back to this facility and offered testing, breathing questionnaires, and breathing tests to some of these workers, we’re looking at what’s happened over the past 10 to 13 years with these workers. RL: I think it’s also going to be important to look at other techniques for sampling flavorings. One thing I’ve been doing is using evacuated canisters to sample whole air. Instead of using a sorbent and drawing air across it, you just collect your air into a canister and then take it back to the lab and analyze it. It’s a lot easier in the field: all the onus of analysis is on the laboratory people, so it makes the field IH happy. It’s fairly easy to sample. Also, in order to understand these peak exposures, we’re interested in identifying and using sensors or technologies that would be able to capture the low levels that we want to look at because the RELs are so low. RB: If you have a worker exposed in a workplace that [uses] 2,3-pentanedione and they’re having symptoms—shortness of breath on exertion, a cough, wheezing—it’s important to consider obliterative bronchiolitis and remove them from exposure until they’re evaluated. It’s very important to do that because the disease can be so severe and because it’s irreversible. And certainly if workplace air levels for diacetyl and 2,3-pentanedione are above the NIOSH proposed RELs for these two chemicals, it’s recommended that a medical surveillance program be initiated in the workplace that includes spirometry and a questionnaire that asks about respiratory symptoms and their work history and tasks to determine if their lung function is decreasing over time. You want to catch it as early as possible to stop the decline, because the disease can be so debilitating. RL: We’re interested in characterizing exposures in cafés in addition to the coffee processing facilities. RB: Yes, some of the coffee processing facilities either have a café attached or a standalone café, so we will be doing some air sampling in these cafes as well as offering medical testing to the café workers.
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An Interview with Rachel Bailey and Ryan LeBouf: see the sidebar at the end of this article.