New IMO Confined Space Entry Rules | RESOLUTION MSC.581(110) | Louis Safety | Marine and Ship safety company | Abu Dhabi ,UAE | Marine Calibration

Confined space incidents remain one of the leading causes of fatalities in the maritime industry. In many cases, accidents occur when enclosed spaces are entered without proper atmospheric testing, supervision, or rescue preparedness. To address these ongoing risks, the International Maritime Organization’s Resolution MSC.581(110) — Revised Recommendations for Entering Enclosed Spaces Aboard Ships — entered into force on 3 December 2025 and is now fully applicable across the global maritime industry. As a result, ship operators are expected to follow stricter procedures, improve risk assessments, and strengthen crew preparedness.

Updated IMO Guidance (MSC.581(110))

The revised IMO guidance establishes clearer responsibilities and more rigorous safety practices for ship operators and crew when entering enclosed spaces. In particular, the focus has shifted toward prevention, structured controls, and documented accountability.A major emphasis in the revised recommendations is the monitoring of Carbon Dioxide (CO₂), which is now recognized as a critical hazard in enclosed spaces. Elevated CO₂ levels can act as a powerful asphyxiant, causing dizziness, confusion, rapid unconsciousness, and death — often without noticeable warning sign.

Key Safety Requirements

First, comprehensive multi-gas testing must be completed before entry
Additionally, single-person entry into enclosed spaces is strictly prohibited
Furthermore, adjacent or connected spaces must also be tested
Moreover, entry permits now have limited validity and require revalidation
Finally, vessels must maintain space-specific emergency rescue procedures

Importantly, atmospheric testing must include CO₂ measurement in addition to oxygen and toxic gases, because high CO₂ concentrations can impair breathing even when oxygen appears within normal limits. Together, these measures help prevent sudden exposure to oxygen-deficient or toxic atmospheres that can lead to unconsciousness or fatality within minutes.

Why These Rules Are Critical

Enclosed spaces on ships — including ballast tanks, fuel tanks, cargo holds, and void spaces — often contain invisible hazards. For example, toxic gases such as carbon monoxide or hydrogen sulphide may accumulate without warning. At the same time, oxygen levels can fall below safe breathing limits. In addition, CO₂ build-up can occur due to cargo reactions, combustion processes, or biological activity, creating an atmosphere that displaces oxygen and suppresses normal breathing response. Because of this, relying on visual inspection alone is extremely dangerous.

Under the revised guidance, vessels are now required to implement structured safeguards. Specifically, operators must identify all enclosed spaces through risk assessment, use certified multi-gas detection instruments, and maintain documented entry permit systems. In addition, crew members must be trained in hazard recognition and emergency response procedures. Ultimately, this approach promotes preventive safety culture rather than reactive action after an incident occurs.

What Ship Operators Must Do Now

To align with the new IMO recommendations, operators should take several immediate steps. First, the Safety Management System (SMS) should be updated to reflect the revised enclosed space entry procedures. Next, vessels must ensure the availability of calibrated multi-gas detectors capable of measuring CO₂ as well as O₂, CO, and H₂S. Equally important, structured entry permit procedures should be implemented and monitored. Beyond that, crew training on confined space hazards should be conducted regularly. Finally, documented rescue plans must be established for each enclosed space onboard.

Clearly, compliance is not just a regulatory requirement — it directly protects lives.

Gas Detection Compliance Support from an ADNOC-Authorized Vendor

Accurate atmospheric testing forms the foundation of safe enclosed space entry. Therefore, using reliable and certified gas detection equipment is essential for early hazard identification — especially for CO₂ detection, which is now a highlighted requirement under MSC.581(110). In this context, We are an authorized vendor for Abu Dhabi National Oil Company (ADNOC), supplying advanced multi-gas detection solutions for maritime and offshore sectors