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Carbon Monoxide Poisoning From Industrial Coffee Extraction
To the Editor: The process of commercial coffee roasting releases large amounts of carbon monoxide (CO),1 which sometimes reach life-threatening levels.2 We report a case of a death due to CO poisoning sustained during commercial coffee roasting.
Report of a Case
A 23-year-old employee of a roasting plant collapsed and lost consciousness soon after entering a storage tank (approximately 2 m in diameter and 2.7 m in height) to retrieve a tool that he had dropped into the tank. When removed from the tank 40 minutes later, he was found to be in a state of cardiopulmonary arrest and was transported to the hospital. Resuscitation attempts, including cardiac compression and administration of 100% oxygen, were unsuccessful.
Five coworkers also were transported to nearby hospitals. Three of these had collapsed and lost consciousness when they went inside or approached the tank, while 2 others reported presyncopal symptoms. All 5 recovered soon or within a few hours, although 1 was hospitalized and given oxygen.
The medicolegal autopsy of the deceased worker was performed in our department 17 hours after the death. A cherry-red discoloration was seen on the back. Slight bruises were found on the left temporal area and the left forearm. Multiple petechial hemorrhages were observed in the pericardium and on lung surfaces. Both lungs showed severe edema and congestion. The concentration of CO hemoglobin (COHb) was 26% in the heart blood. No other toxic gases or drugs were detected. The cause of death was determined to be acute CO poisoning.
According to the result of the subsequent forensic inspection, the company involved in this incident uses an extracting process on coffee beans that have already been roasted and ground. This process, which is widely used in the industry, involves adding water to ground beans in an extracting tank to produce a coffee extract that is then transferred to a storage tank.
Air samples from storage tanks were collected throughout the roasting process for the determination of CO levels. In this case, the maximum levels of CO in the storage tank were found to be 10 000 to 100 000 ppm. An ambient CO concentration of 5000 to 10 000 ppm can lead to a COHb saturation of as high as 75% (a lethal level) within a few minutes.3
Comment
Industrial coffee extraction may place workers at risk of CO poisoning. Workplace standards, improved industrial systems, and better worker education may help to reduce this risk.
Fusae Nishimura, DVM, PhD;
Shuntaro Abe, MD;
Tatsushige Fukunaga, MD, PhD
Department of Forensic Medicine and Sciences
Mie University School of Medicine
Mie, Japan
1. Clarke RJ. Roasting and grinding. In: Clarke RJ, Macrae R, eds. Coffee Technology. Vol 2. New York, NY: Elsevier Applied Science Publishers; 1987:73-89.
2. Newton J. Carbon monoxide exposure from coffee roasting. Appl Occup Environ Hyg. 2002;17:600-602.
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3. Logemann E, Werp J. Forensische toxikologie. In: Foster B, ed. Praxis der Rechtsmedizin. New York, NY: Georg Thieme Verlag Stuttgart; 1986:674-781.
Letters Section Editor: Stephen J. Lurie, MD, PhD, Senior Editor.
JAMA. 2003;290:334.
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