Lung cancer cases in school cafeterias in South Korea

Jinwoo Lee, Director, Paju Hospital Workers’ Health Promotion Center, Gyeonggi Medical Center

A workerse was diagnosed with lung cancer in 2017 after working in a school cafeteria in Gyeonggi Province for 12 years. She died while fighting the illness and her lung cancer was recognized as an occupational disease in February 2022. Lung cancer in this cafeteria worker was recognized as an occupational disease because cooking fumes can contain hazardous substances generated from frying foods. Several studies suggest that workers in an environment similar to Korean school cafeterias have a higher risk of lung cancer. Cooking fumes are composed of particulate matter with a very small diameter and volatile organic compounds are adsorbed on these particles. Particulate matter can cause various lung diseases and volatile organic compounds measured in cafeterias include polycyclic aromatic hydrocarbons and formaldehyde which are classified as carcinogens by the International Agency for Research on Cancer.

Poor work environment, hood wind speed ‘0m/s’, cafeteria, cancer, occupational health

Industrial hygienists from the Paju Hospital Workers’ Health Promotion Center inspected the air quality of eight schools in northern Gyeonggi Province. The results of the hood wind speed check revealed serious problems. Each school usually installs 4 to 6 hoods for ventilation, but in two schools, some of the hoods were broken and did not work at all. In other schools, the hood worked, but the wind speed difference between the hoods was large, and most of them did not meet the regulatory standards (1.0-1.2 m/s) of the Korean Occupational Safety and Health Act. In particular, the wind speed at the location of the worker’s breathing point or the point of harmful substance generation was very weak. In four schools, the hood wind speed at the breathing point was 0 m/s.

Currently, most school cafeteria ventilation systems are upward hoods (often a canopy type) for sucking the hot rising air flow generated during the cooking process. However, if the worker’s breathing area is located in the hood, this system can adversely affect the health of workers because the cooking fumes go through the breathing point as they are sucked over their heads. It is necessary to investigate whether this hood problem is limited to only some schools or if it is a universal problem in most school cafeterias.

The Korean Ministry of Labor’s safety guidelines for cafeteria facilities also state that, “the hood should be installed in an enclosed or outside type”. Current cafeteria ventilation systems should be standardized to maximize exhaust efficiency, rather than the less-protective systems often used currently.

Since the air quality was measured using a direct-reading method, it is difficult to directly compare it with the usual work environment measurement result or the standard 8-hour average (TWA) under the Korean Occupational Safety and Health Act (OSH Act). Formaldehyde levels in 7 out of 8 schools (88%) were higher than the TWA standard value of 0.3 ppm in the OSH Act. In one elementary school, formaldehyde was measured at 4.4 ppm – approximately 15 times higher the TWA regulatory standard. The South Korean TWA regulatory standard for formaldehyde is considerably weaker than other governmental regulatory standards. For example, in the European Union, formaldehyde levels should not exceed 0.2 ppm in 8 hours, and in the United States formaldehyde should not exceed 0.1 ppm. Some countries also stipulate a short-term exposure standard (STEL), which is a time-weighted average exposure value of 15 minutes. The formaldehyde concentration of 4.4 ppm at an elementary school in this study is 15 times higher than the 15-minute short-time exposure standard in the United States.

Difficulty in managing the cafeteria work environment

In the current Korean Occupational Safety and Health Act, cooking fumes are not included in the materials subject to work environment measurements. It may take some time to establish a method for measuring cooking fumes. The instantaneous concentration of formaldehyde was high in this investigation, and its existence has been confirmed in other previous studies. However, if the relatively weak TWA standard of the Korean Occupational Safety and Health Act is applied (0.3 ppm vs. 0.1 ppm in the US), the 8-hour average value may not exceed the regulatory limit in many cases. This should be addressed by strengthening Korean regulatory standards for formaldehyde and other relevant substances.

As the work environment measurement and health monitoring items for cooking fumes are not currently defined, no information is routinely obtained about these potentially harmful exposures at work and they are not properly incorporated into the regulatory system. In addition, there are different exposure limits in different countries for hazardous substances such as formaldehyde. As a result, sometimes substances are not considered problematic because their measured values are lower than the exposure standard. These current realities undermine worker health and safety.

Regarding exposure standards, the standards for chemical substances and physical factors by the Korean Ministry of Employment and Labor define “a standard that does not adversely affect the health of almost all workers at a level below the exposure limit when workers are exposed to harmful factors”. The exposure standard is not a standard that is safe for everyone, and it is not a standard for all hazardous substances. In addition, it is not a standard for all routes of exposure and it is not an objective, absolute number, but a socially-agreed standard determined by debate and the power of various private and public sector stakeholders. Rather than arguing whether there are current exposure limits and violations, the key is how to prevent and minimize exposure to these substances.

In a recent national inspection, Im Jong-seong, a member of Parliament, reported that 7 cafeteria workers were compensated for lung cancer as an occupational disease, and deliberation on an additional 10 cases is currently in progress. As of September 2021, 49 cases of cancer patients in school cafeterias were identified by ‘Occupational Cancer 119’, a recently launched occupational cancer campaign by a public interest non-governmental organization. The campaign received reports of various cancers in cafeteria workers including 24 lung cancers, 11 breast cancers, 6 thyroid cancers, and 4 blood cancers. Because of exposure to various carcinogens and poor ventilation, cancers other than lung cancer might be associated with cafeteria work. Since many cafeteria workers have already been diagnosed with cancer, the cafeteria working environment should not be left unattended due to delays in the regulatory process.

How to prevent occupational cancers in the cafeteria

In order to prevent further cancer occurrence in school cafeterias, it is essential to monitor and improve local exhaust systems. Article 93 of the Korean Occupational Safety and Health Act Safety stipulates that local exhaust systems must be inspected for safety every two years. According to the law, exhaust systems should be officially inspected by a safety inspection institution and the results should be disclosed to workers. Based on the results, the Occupational Safety and Health Committee in the school should discuss and implement actions to improve the ventilation system sequentially according to the condition of the local exhaust system.

There is also a need to decrease labor intensity. The Korean Ministry of Employment and Labor notes that, “Exposure standards were established based on 8 hours of work per day. Conditions, abnormal atmospheric pressure, etc. may affect the application of exposure standards, so these factors should be specially considered”. However, in the school cafeteria, exposures to cooking fumes, fine dust, and various carcinogens occur under conditions of high labor intensity. One cook is typically in charge of preparing food for 120 to 150 people. This is twice as many people as other types of cafeterias. Due to the high labor intensity and elevated respiratory rates, the potential effects on health can be significant even at relatively low concentrations of toxic substances. In order to prevent occupational cancers such as lung cancer from occurring in the cafeteria, it is necessary to control the intensity of labor by reducing the number of people served per cook, as well as reducing the temperature of overheated work areas. 

Cooking fumes should also be reduced. Cooking fumes generated from high-temperature fried dishes are a risk factor for lung cancer, and cooking fumes are generated not only by frying but also by cooking methods such as stir-frying and roasting. Several Korean studies and surveys estimate that school cafeteria workers will be exposed to high concentrations of cooking fumes three to four times a week, considering indirect exposure. Rather than relying solely on roasting, stir-frying, or frying, cafeterias should increase menus which can be made in a way that generates less cooking fumes, such as steaming.

Activities for prevention of occupational cancer

Occupational cancer is a disease resulting from occupational exposures. Occupational factors are usually estimated to be 4-5% of the attributable risk for all cancers. In Korea, where there are about 240,000 cancer patients annually, it can be estimated that there are approximately 9,700 occupational cancer patients annually. However, in reality only about 200 (~2%) patients are recognized as occupational cancer patients each year. What can be done to detect and prevent occupational cancers?

First, it is necessary to amend the various laws related to carcinogens that do not provide uniform regulation. Even in official data such as the Korean Ministry of Labor’s Work Environment Survey Report, it is difficult to clearly understand the situation of workplaces handling carcinogens. Regulations for identified substances are also lacking. There are 44,000 chemical substances in circulation in Korea, of which 6,800 have been identified as hazardous, and 300-400 new chemical substances are introduced every year. However, exposure standards have been set for only 731 substances under the Occupational Safety and Health Act. As a result, the occupational health service system is also limited. Workplace environment measurements cover only 192 substances; special health exams are required only for 181 substances; and health management tracking and exams are mandated for 15 carcinogens.

To prevent occupational cancers, it is necessary implement the precautionary principle. If the workplace currently includes carcinogens and other harmful factors, managers should not be satisfied only with the results of the required work environment measurement and special health examination, but also look for ways to use substitution to prevent and minimize the use of hazardous substances and subsequent exposures. Examples of this approach in Korea include the ‘carcinogen elimination project’ and the solidarity project with the ‘carcinogen surveillance network’ carried out by the Korean Metal Workers Union. If a labor union has successfully carried out a carcinogen elimination project in a single company, the model could be expanded to other companies using similar processes and substances. In order to reduce the use of carcinogens in small businesses, support from local governments is also needed. It is necessary to consider ways to ban the use of carcinogens and other harmful substances and to provide support for analysis and implementation of safer substitutes.