A notice explaining Incheon's chemical accident safety signal system [Incheon City]
A notice explaining Incheon's chemical accident safety signal system [Incheon City]

A series of chemical misfill accidents in Incheon last year left multiple workers dead or injured, prompting the city to build a new chemical safety management framework designed to eliminate human error at the source.

The centerpiece of the effort is a "chemical accident safety signal" system that goes beyond simply telling workers to be more careful. It assigns each chemical a unique color applied consistently across storage tanks, pipes, valves and fill ports — and adds physical coupling devices to prevent wrong connections altogether — with plans to roll the system out to private workplaces.

According to Incheon City, workers at the Incheon Environment Corporation's Gongchon facility injected sodium hypochlorite into an aluminum sulfate storage tank in August last year, injuring four people.

The following month, at a semiconductor manufacturing factory in Michuhol-gu, sodium chlorate was mistakenly injected into a hydrochloric acid storage tank, injuring 25 people. Both incidents are prime examples of how a momentary lapse can trigger the release of toxic gas.

According to the Chemical Substances Information System, 49 chemical accidents occurred in Incheon between 2014 and 2025, killing five people and injuring 92.

Facility defects and failure to comply with safety standards accounted for 93.9 percent of accident causes. Last year alone, eight accidents killed one person and injured 30 — the highest casualty toll in the past 12 years.

City officials noted that these accidents do not stem from worker carelessness alone, but from inconsistent on-site labeling systems that allow momentary mistakes to escalate into major incidents.

Storage tanks typically display the name of the chemical they contain, but pipes, valves and fill ports are often marked only with management numbers or carry outdated labels — conditions that can confuse even experienced workers.

In response, the city last year piloted the safety signal system across 13 facilities and 103 chemical-handling sites operated by the Incheon Environment Corporation. Each chemical was assigned a distinct color — green for sodium hypochlorite, blue for aluminum sulfate, yellow for sodium hydroxide — applied uniformly to storage tanks, pipes, valves and fill ports.

Dedicated couplings were also installed to prevent hoses carrying different chemicals from being connected to the wrong tanks.

The diameter and structure of each coupling were designed to differ by chemical, so that even if a worker misreads the color markings, a physical connection simply cannot be made.

Starting this year, the city is expanding the system to private businesses that handle hazardous chemicals.

Participating facilities will receive on-site expert consultations to analyze the chemicals they handle and their processes, with tailored color-coding schemes and dedicated coupling installations provided as support.

From 2026 to 2027, the city plans to compile field application cases and develop industry-specific standard guidelines. Over the longer term, it intends to petition the central government to adopt the prevention model — validated in Incheon — as a national chemical safety management standard.

"The chemical accident safety signal system is not about asking workers to be more careful — it is about creating a work environment where human error does not lead to accidents," a city official said. "We will spread the experience validated at public facilities to the private sector, develop it into a national safety management standard, and dramatically reduce chemical accidents."


gilbert@heraldcorp.com