Weekly Contributions

Occupational Lung Disease Recognized through an Epidemiological Investigation

Bongsoo Jung (Labor Attorney, KangNam labor law firm)

 

I. Introduction

When an employee applies for compensation for an occupational illness, the Korea Workers’ Compensation & Welfare Service (hereinafter referred to as “COMWEL”) determines whether the employee has an occupational illness or not through its own investigation, the opinions of a medical professional (or professional agency), and a review by the Occupational Disease Determination Committee. In cases where its own investigation is unable to determine whether there is a relationship to work, COMWEL can ask a professional agency to conduct an epidemiological investigation, through which it will determine whether the illness in question is an occupational illness or not. Such illnesses as black lung disease (Pneumoconiosis) and lead poisoning, and conditions such as noise-induced deafness are more easily linked to occupation than some other illnesses such as cancer, hemoptysis (vomiting blood), asthma, and dermatitis are not so easy to link. In this case, gathering information on the working environment will be of considerable help.

I would like to introduce a case of occupational illness which resulted in death from vomiting of blood. The employee in question had had a lung illness for a long period of time, and along with severe coughing, became worse from his harmful working environment. The labor attorney for this case claimed, on the basis of a statement from his surviving family, that the industrial illness victim (hereinafter referred to as “the employee”) died from his long-term illness deteriorating through exposure to harmful chemicals like sulfuric acid in the process of zinc smelting. The labor attorney submitted an application for survivor’s benefits without a direct investigation. After receiving the application, COMWEL asked a professional agency (the Occupational Lung Disease Research Institute) to conduct an epidemiological investigation. Once the results were in, COMWEL concluded a close relationship between the employee’s workplace environment and the exacerbation of his illness, accepting his death as due to a work-related illness. 

 

II. Summary

(1) The employee had worked at a zinc smelting factory since 2016. When he died at Aju University hospital at age 61 on December 16, 2021, his spouse applied for Survivor’s Benefits on February 29, 2022 to the COMWEL Youngju Office.

(2) On December 9, 2021 when the employee began vomiting blood and experienced difficulties in breathing, he was admitted to Wonju Christian Hospital where he continued to vomit blood and suffer from pneumonia. He died from respiratory and organ failure on December 16, 2021.

(3) Since joining OO zinc smelting company[1] on June 12, 2016, the employee had worked as a machine operator in charge of a filter press machine for a total of 5 years and 3 months. The smelting process at a filter press extracts zinc by dividing cake (solids) and filtrate (liquid) after melting sludge coming from a sludge container. The employee swept up the cake on the floor when it fell in the process of dividing from the filtrate. In this smelting process, sulfuric acid[2] was used and the employee was continuously exposed to the sulfuric acid gas.

(4) Before beginning employment at OO company, the employee had worked as a street cleaner from 2011 to 2015 (aged 51 to 55) from 4 am to 4pm, during which he began suffering from, and receiving treatment for, bronchitis and obstructive lung disease due to early morning cold air.  

(5) As mentioned, the employee had been exposed to sulfuric acid gas, mineral dust, etc. continuously at the workplace while suffering from existing bronchitis and obstructive lung disease. In addition to this, the employee had to work longer hours than normal for a long period, which, combined with the stress from worry he would lose his job due to his poor health, was claimed to have caused pulmonary (lung) hypertension, resulting in his vomiting blood and ultimately his death.

(6) Fifteen months after his spouse applied for Survivor’s Benefits, during which COMWEL conducted an investigation, received medical opinions, and the results of an epidemiological investigation, the Occupational Disease Determination Committee agreed that the employee died from an occupational illness.  

 

III. The Limits of Investigation and Request for Epidemiological Investigation

1. The applicant’s difficulties in investigating for herself

  In the application for Survivor’s Benefits, the applicant claimed that the employee had suffered from chronic fatigue due to working in two shifts for a long period of time; had stress and insomnia due to worries over losing his job because of his illnesses; and had been exposed to a harmful working environment (including sulfuric acid), which had caused pulmonary hypertension, vomiting of blood, and his death. The claim that the employee suffered from fatigue and stress could be causes for stroke or heart disease, but not for vomiting blood. Accordingly, the applicant had to verify that the workplace’s harmful substance (sulfuric acid) had exacerbated the employee’s existing conditions of bronchitis and obstructive lung disease and had caused pulmonary hypertension and vomiting of blood. However, the applicant was not able to gain access to the workplace, and had to depend on the COMWEL investigation. The following is the result of the epidemiological investigation from the professional agency commissioned by COMWEL.

 

2. COMWEL request for an epidemiological investigation

When there is difficulty in determining whether an illness is occupational or not, COMWEL can ask for professional opinions from a medical doctors’ advisory council, the industrial safety and research centers of the Korea Industrial Safety Corporation, or other agencies that can evaluate occupational diseases. Also, the Medical Care Processing Rules describe that when it comes to difficulty in determining recognition of an occupational illness concretely, COMWEL may ask relevant institutes (such as medical doctors’ associations or industrial safety research institutes) to give advice and participate in the investigation. This includes cases 1) where it is difficult to verify whether the employee’s existing illness affected the occupational illness, 2) where meaningful difference exists between the medical doctor in charge and the advisory doctor regarding clinical signs that will show the degree of the employee’s exposure to harmful materials, 3) where it is difficult for a doctors advisory council to determine relation of an illness to occupation, or where there are no criteria for the occupational illness, and 4) where an epidemiological investigation is necessary to recognize whether a cause-and-effect relationship exists between work and illness. Upon concluding this investigation, as long as there is no clear evidence to disprove the illness was work-related, it should be accepted as an occupational illness.

3. Epidemiological investigation and recognition of the occupational disease by the Occupational Lung Disease Research Center
(1) Understanding workplace environment
   The employee’s work was to operate the filter press (F/P disintegration) machine to retrieve a small amount of metal out of sludge coming from a sludge container. In this process, the employee was exposed to steam and carbon monoxide (CO) from the leftover liquid and cake. There is no artificial ventilation system in the disintegration process of the filter press, but there is natural ventilation in the roof of the three storey building. The agency measured the air quality of the workplace twice: on October 10, 2012, for 5 hours and 40 minutes to check the internal air of the workplace with a multiple gas measurement instrument; and on March 26 & 27, 2023, for 20 hours to check carbon monoxide concentrations in the air near the filter press, with a carbon monoxide measurement device. Additionally, workers’ individual exposure was measured by affixing the measurement instruments to the waists of three workers onsite for twenty hours.
  The results of measurement showed an average density of 38ppm of carbon monoxide in the work area around the filter press. At the height the worker was breathing at the top of the F/P machine, concentrations exceeded 500ppm, the limit of the measurement instrument. Individual measurement done for 20 hours averaged 19ppm, 60% of the exposure limit according to the Ministry of Labor. However, as time passed, the density of carbon monoxide increased up to a maximum of 185ppm. Besides carbon monoxide, hydrogen sulfide was detected at an average of 5.1ppm.

 (2) Effects of carbon monoxide & hydrogen sulfide on the human body
  The normal concentration of carbon monoxide is 0.1~0.2 ppm. This carbon monoxide combines with hemoglobin delivering oxygen to the body, and results in carboxy-hemoglobin, causing hypoxia (low oxygen levels in the blood). This contracts blood vessels in the lungs and increases resistance of lung vessel (lung rigidity), which causes pulmonary hypertension. As mentioned, hydrogen sulfide was also measured at an average of 5.1ppm around the filter press. If a healthy adult is exposed to hydrogen sulfide up to a density of 50ppm, pulmonary edema (fluid into the lungs) appears. Exposure to a density of 5.1ppm of hydrogen sulfide could not cause lung damage, but hydrogen sulfide just like carbon monoxide is also chemical material to influence lung hypertension. Accordingly, as the employee had repeatedly been exposed to a high concentration of carbon monoxide, this mixed exposure to hydrogen sulfide could have affected the occurrence of lung hypertension.   
 (3) Occupational illness
   The employee, who had been exposed to a density of carbon monoxide since December 2016, experienced headaches and a decline in physical abilities that could have been due to the carbon monoxide exposure. Moderate lung hypertension was diagnosed in August 2020, four years after beginning employment at the zinc smelting company. This had become severe hypertension by October 2021. Upon reviewing medical records from that time, no diseases were diagnosed that would be responsible for lung hypertension. It could, however, have occurred from the repeated exposure to a high density of carbon monoxide in the course of working at his last workplace, and possibly from the exposure to hydrogen sulfide. Lung hypertension causes vomiting of blood. This hemoptysis (vomiting of blood) does not reverse easily, and can easily reoccur even upon improvement. It was therefore concluded that the employee died from the vomiting of blood, caused by lung hypertension.
  
IV. Determination of Occupational Illness

Making a determination of whether occupational illness exists or not through epidemiological investigation requires time and money, but provides objective and scientific processes, allowing both the employee and the decision-making body to easily accept the findings. Accordingly, the use of a professional agency to conduct the epidemiological investigation is recommended, and can help stop further occupational illness in the early stages by providing accurate data on harmful factors in the workplace.

<Determination of occupational illness>
  1) According to the epidemiological investigation submitted by the professional agency that COMWEL commissioned, the employee had been exposed to carbon monoxide and hydrogen sulfide together, causing lung hypertension which in turn resulted in vomiting of blood and death. It is therefore determined that the employee’s death was from occupational illness.
  2) The advisory medical doctor to COMWEL stated that lung hypertension had been the result of repeated exposure to a high concentration of carbon monoxide, which had caused acute respiratory failure and acute pneumonia, leading to death.
  3) The Occupational Disease Determination Committee reviewed the investigation findings, the examinations submitted by COMWEL and based on medical opinions, and the measurements of the workplace environment conducted by the professional agency. The Committee determined that the employee’s lung hypertension was the result of repeated exposure to carbon monoxide and hydrogen sulfide, with complications such as vomiting blood, and resulted in the employee’s death.
  Based upon the above facts and medical opinions, this employee’s death can be admitted as a result of occupational illness according to Article 37 of the Industrial Accident Compensation Insurance Act.