The most important shift is clear: atmospheric testing must go beyond oxygen.
The IMO formally accepted a revision of Resolution A.1050(27) at its 110th session in June 2025, approving updated Recommendations for Entering Enclosed Spaces Aboard Ships. The update ties directly into the ISM Code, where company procedures, risk assessments, and safety management systems are expected to reflect the new recommendations.
The revision takes one of the most hazardous operations at sea — entering enclosed spaces — and aligns procedures with today’s realities. New findings on carbon dioxide in particular show why crews and superintendents can no longer rely on oxygen checks alone.
Research presented to the Sub-Committee highlighted how cargo holds can “breathe” when hatch covers are not fully gas-tight. As temperature and pressure fluctuate, air seeps in and out. Oxygen levels may appear normal, but CO₂ accumulates silently.
This is a hidden hazard: a space can pass an oxygen test, yet still expose a crew member to dangerous levels of CO₂. The revised recommendations address this risk directly, making CO₂ monitoring part of the expected testing routine.
They also clarify definitions such as connected and adjacent spaces, helping crews understand exactly which areas require testing before entry.
The revision sets a new expectation: safe entry cannot be cleared on oxygen alone. Inspectors will now look for evidence that testing routines reflect the broader hazard picture. In practice, this means:
Alongside equipment and records, training is expected. Crews must understand which gases could be present in a given space, and how to interpret results, not just rely on a single reading.
With these steps in place, safe entry moves from being a single oxygen reading to knowing the whole atmosphere before anyone steps inside.
The revision of Resolution A.1050(27) is not just a change in wording. It is a change in practice. By expanding gas testing, the IMO aims to prevent hidden hazards and make enclosed space entry safer and clearer. It also places greater weight on company responsibility and safety culture to ensure that procedures are consistent, documented, and verifiable.
At Bruusgaard, we help operators meet this higher standard with multi-gas detection solutions, calibration gas supply, online training, and systems that support documentation.
With the right equipment, knowledge, and procedures in place, compliance with the ISM Code and IMO recommendations becomes more than achieving compliance — it becomes a safety net that protects both crews and operations.