Lessons Learned: Prior to an enclosed space entry, a safety meeting is vital

Two technicians lost their lives after being exposed to hazardous levels of hydrogen sulfide in No. 2 COT (S) tank. Although the crew managed to evacuate the unconscious technicians, both were pronounced dead upon arrival at the hospital.

The technicians entered the tank despite several safety lapses: the tank had not been ventilated, the atmosphere had not been tested, and no work permit had been issued. Although the AB and officer of the watch were aware of their intention to enter the tank, they did not intervene.

The DMAIB investigation sought to understand why the technicians proceeded with the entry and why the crew failed to act. Multiple interrelated factors contributed to the technicians’ assumption that the tank was safe:

• The tank was empty, the hatch was partially open, and the entry had been previously discussed.
• Other tanks had been entered earlier that day without atmospheric issues.
• No warning signs or safety equipment were present at the tank entrance, which was not unusual due to informal judgments often made about required safety gear.

Furthermore, the technicians had just completed an inspection of the forepeak tank without incident and did not find the lack of safety gear at No. 2 COT (S) entrance alarming.

There was no expectation that the tank contained hydrogen sulfide. The MSDS for the cargo (soybean oil) did not indicate a risk of toxic gas, and no such gas had been detected in other tanks. However, hydrogen sulfide had formed due to the reaction between soybean oil residues and seawater that had remained in the tank for 19 days.

The gas, being heavier than air, settled at the bottom of the tank and was not detected by the AB on watch. Inside the tank, the technicians could not smell the gas due to the paralytic effect of high hydrogen sulfide concentrations on the sense of smell.

Communication gaps further compounded the situation. The crew aware of the technicians’ plans had not attended the morning safety meeting and did not know which tanks were scheduled for entry. Watch handovers on the bridge did not cover ongoing deck work, as responsibilities were limited to logging time and atmospheric values for the permit system. The chief officer, the only person with a complete overview, was resting after a long shift.

Work Permit and Procedure Failures

DMAIB’s investigation revealed significant weaknesses in both the work permit and procedural systems:

• The procedure was inconsistent with the work permit and lacked clear, structured guidance for critical tasks, emergency responses, and equipment requirements.
• The document was treated more as a reference containing inconsistent and sometimes irrelevant information, rather than a step-by-step guide.
• As a result, the procedure was rarely printed or reviewed regularly and was seen as cumbersome for frequent enclosed space entries.

The work permit system also had flaws:

• It included discretionary phrases that encouraged crew members to make subjective judgments rather than follow standardized procedures.
• It was not designed to prescribe specific actions but to authorize entries and assign responsibility.
• Because it was managed by a single officer, gaps in oversight emerged when that officer was unavailable.
• Misunderstandings could occur over whether a permit had actually been issued, undermining the permit’s effectiveness in hazard management.

Enclosed space entries on board were frequent and often competed with other operational priorities, such as cargo discharge, meetings with surveyors, or anchor watches. The chief officer was central in balancing these competing demands. However, the permit-to-work system’s reliance on one individual and its ineffective design ultimately failed to ensure safety.

DMAIB concluded that the issue was not the crew’s willingness or competence, but rather the inadequacy of the procedures and permit system as tools for managing work in dynamic conditions.

Key Preventive Measures Implemented

1. Mandatory pre-entry safety meetings: An extraordinary safety meeting must be held before any enclosed space entry. The meeting must include a review of the entry plan and risk assessment.
2. Safety campaigns: Monthly newsletters now include campaigns focusing on enclosed space entry procedures and the use of stop-work authority. These initiatives aim to raise awareness and address risk normalization.
3. Procedure revisions: Procedures for enclosed space entry, contractor management, simultaneous operations, toolbox meetings, and training forms have been thoroughly reviewed and updated to ensure alignment between compliance requirements and actual practice.
4. Pre-joining briefings: New joiners are briefed on the incident and its causes to underscore the importance of following correct procedures.
5. Training enhancements: Training intervals have been reduced, and new modules introduced. In-house training now includes incident learnings and covers the risks of putrefaction on chemical tankers.
6. Onboard training and drills: Superintendents or port captains have visited all vessels to conduct onboard training. Topics include permit-to-work systems, leadership, emergency communication, stop-work authority, and safety culture.
7. Safety recognition program: This program rewards effective use of stop-work authority and is discussed during safety committee meetings to reinforce positive behavior.
8. Just culture approach: The investigation process applied a just culture model, emphasizing the management’s responsibility to provide adequate training, support, and resources.