Recent assessments by the International Maritime Organization (IMO) have identified a critical trend in hydrogen sulphide (H₂S) fatalities within the maritime industry, indicating that more than half of such incidents occurred during routine operations outside of enclosed spaces. This revelation underscores the need for a comprehensive reassessment of safety protocols for crew members engaged in daily maintenance activities.
The Incident
The findings, detailed in document CCC 12/INF.20 issued on 10 July 2026, point to at least 29 of the 56 H₂S-related deaths having transpired in open areas while crew members were executing standard tasks. A specific case highlighted involved a Second Engineer (2/E) and a Motorman who, prior to cleaning a bilge water tank on a drillship, opened the tank access hatch to allow for ventilation. Tragically, the 2/E suddenly collapsed just after opening the hatch, leading to both men falling into the tank, resulting in fatalities despite immediate rescue efforts.
The investigation revealed that the tank contained oily water and deposits capable of creating H₂S. The act of opening the hatch reportedly released accumulated gas, exposing the crew to lethal concentrations of H₂S in the vicinity of the pump room.
Understanding H₂S Hazards
H₂S is a colorless, odorless gas known for its toxicity and flammability, often formed when organic materials decompose in the absence of oxygen. On vessels, sources such as oily slops, sewage, and bilge residues provide conducive conditions for sulphate-reducing bacteria to generate H₂S. While low concentrations may emit a rotten egg scent, this odor is unreliable as a warning; exposure can lead to a rapid desensitization of the sense of smell.
The term ‘H₂S knockdown’ describes the phenomenon of rapid collapse following exposure to high concentrations of the gas. Affected individuals can lose consciousness within moments if concentrations exceed critical thresholds, often before any preventive actions can be initiated.
Operator Response
In light of these findings, operators are urged to revisit safety training and equipment protocols regarding routine maintenance tasks, especially those involving potential exposure to H₂S. Enhanced training on recognizing the signs of H₂S accumulation, understanding its sources, and utilizing portable gas detectors effectively is paramount. Furthermore, establishing stringent procedures for the safe handling of tanks and fluid systems can mitigate risks associated with accidental gas releases during normal operations.
The Operational Read
The emergence of fatalities linked to H₂S exposure during routine shipboard tasks emphasizes a significant lapse in traditional safety perceptions among maritime operators. The notion that H₂S poses a threat only in enclosed spaces has proven inadequate, necessitating immediate action to enhance crew training and establish comprehensive safety procedures against gas releases during common operations. Operators and safety officers must prioritize risk assessments and the implementation of robust monitoring tools. Regular drills and revised safety protocols should aim to inform crew members of the potential dangers present even in seemingly benign maintenance activities, thus fostering a safer working environment aboard vessels.
