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Leading up to the Chuseok holiday in October this year, two workers tragically lost their lives in an asphyxiation incident in Gimhae. The police and the Ministry of Employment and Labor are currently considering the application of the Serious Accidents Penalty Act. It is noteworthy that a similar incident occurred just four months prior in a nearby area, claiming the lives of two individuals due to asphyxiation. Asphyxiation incidents pose a significant threat, especially to confined space workers.

The primary cause of fatalities among workers is oxygen deficiency, a condition manifested when there is an insufficient supply of oxygen. Oxygen deficiency occurs when the oxygen concentration in the air falls below 18%. Causes include the oxidation and corrosion of substances, microbial respiration, and the decay of plants or grains. When the air in a workspace is replaced by other gases, oxygen deficiency can occur. Environments with oxygen deficiency due to these factors have an increased risk of acute poisoning or suffocation.

Accidents resulting from oxygen deficiency typically occur during irregular and temporary work in confined spaces such as manholes, underground shared structures, and tanks. The lack of regularity in these operations often leads to a lack of awareness of the associated risks. Many cases involve workers entering confined spaces without precautions, resulting in fatalities or severe injuries due to oxygen deficiency. To prevent asphyxiation incidents, it is crucial to measure gas concentrations before entering confined spaces and perform regular ventilation. If ventilation is challenging, workers must wear protective gear and equipment.

In an effort to prevent asphyxiation incidents, the government has improved regulations. According to the revised "Temporary Fire Facilities on Construction Sites" as of July 1, areas with a floor area of 150㎡ or more, located underground or without windows, must install gas leakage detectors within 30cm from the floor.

By proactively identifying the potential risks of asphyxiation in workspaces and sharing this information with workers, these incidents can be prevented. Workers who are aware of the risks conduct measurements of harmful air concentrations. Measurements are taken multiple times, including before starting work, before resuming work, and before shift changes. The judgment is made by comparing the maximum value of the measurement results with the appropriate air concentration.

The criteria for observing the appropriate air concentration in confined spaces are as follows:

Oxygen concentration:

18% or higher, less than 23.5%

Carbon dioxide concentration:

Less than 1.5%

Hydrogen sulfide concentration:

Less than 10ppm

Carbon monoxide concentration:

Less than 30ppm (8-hour work exposure limit)


While the fatality rate in general accidents is 1.2% of all casualties, the fatality rate in asphyxiation incidents is alarmingly high at 52.9%. In other words, one out of two individuals involved in asphyxiation incidents succumbs. It is now an obligation for our society to raise awareness of asphyxiation incidents and diligently adhere to safety precautions.


- 밀폐 공간 또 2명 질식 ‘사망’…중대재해법 적용 검토


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BELFOR Contact

Aidil Teper
Phone: +65 6848 1110