At the 110th session of the Maritime Safety Committee (MSC 110) held in June 2025, the Revised Recommendations for Entering Enclosed Spaces Aboard Ships were adopted as IMO Resolution MSC.581(110).
This resolution invited the Assembly to revoke resolution A.1050(27) and aims to prevent fatalities and serious accidents related to enclosed space entry by clarifying requirements for definitions, risk assessment, atmosphere testing, carbon dioxide (CO2) management, and emergency preparedness.

This Technical Information provides an overview of the main amendments and highlights important points to be considered.

1. Outline
Resolution MSC.581(110) is a recommendatory instrument applicable to all ship types.
The resolution recommends that enclosed space entry should be managed within the Safety Management System (SMS) of the Company.
The key focus areas include:
･ Treating enclosed spaces as unsafe until proven safe
･ Enhanced requirements for carbon dioxide (CO2) monitoring
･ Prohibition of single-person entry
･ Establishment of an Enclosed Space Register
･ Development of ship-specific emergency response plans
･ Strengthening of training and drills

2. Application
･ All ship types
･ All personnel who may enter enclosed spaces, including ship's crew, shore personnel, port workers and ship operators.

3. Key Safety Requirements
3.1 Basic Principles for Enclosed Space Entry
･ All enclosed spaces should be considered unsafe for entry until declared safe (4.8)
･ Single-person entry is prohibited (3.11)
･ Entry should only be permitted following: (4.1)
- Completion of a risk assessment
- Issuance of an Enclosed Space Entry Permit

(To be continued)