The Space Looked Fine. Then He Didn't Come Back.

350 Deaths. The Number Has Not Gone Down.

Since 1996, an estimated 350 people have died in enclosed spaces aboard ships. By January 2025, 70 deaths had occurred in just 43 separate accidents since 2022 alone. The IMO adopted new, stronger recommendations in June 2025 specifically because the number of deaths has not decreased — not because the rules weren’t there, but because they weren’t being followed.

Three experienced seamen entered a chain locker. They were not taking shortcuts — they had done it before, many times. What they didn’t know was that corrosion inside the locker had consumed the available oxygen. All three died of asphyxiation before they could be rescued. In another incident, two crew members collapsed in a storeroom adjacent to a cargo hold where oxygen levels had dropped to 6%. They had no atmospheric testing equipment. They had no standby rescue. They died.

Why People Keep Dying

Failure to Test the Atmosphere

The most common single factor. Crew enter a space because it “looks fine,” because they’ve been in it before without incident, or because the testing equipment isn’t immediately available. Oxygen deficiency and toxic gas concentrations are invisible, odourless, and in many cases have no warning symptoms until the person is already incapacitated. A space that was safe yesterday may not be safe today — rust and corrosion consume oxygen. Certain cargoes (grain, coal, iron ore, wood pellets) emit gases that displace oxygen. CO2 — now explicitly included in the revised IMO recommendations — is a potent asphyxiant that can cause rapid loss of consciousness and death.

Inadequate Standby and Rescue Arrangements

A standby person whose only role is to observe the entrant, maintain communication, and raise the alarm immediately if something goes wrong is not a bureaucratic requirement — they are the difference between a rescue and a recovery. Yet investigations repeatedly find that standbys were performing other tasks, were not properly briefed, or were not equipped to respond.

Normalisation of Non-Compliance

China’s Maritime Safety Administration, in a 2025 campaign inspecting vessels in Chinese ports, specifically highlighted unsatisfactory drill execution as a finding. Crew were not practising real enclosed space rescue — they were ticking boxes. When the drill is not taken seriously, the real event is the first time the procedure has genuinely been tested.

Rescue Attempts Without Proper Equipment

A significant proportion of enclosed space fatalities involve the would-be rescuers. A person collapses. A colleague sees them fall and rushes in without atmosphere testing and without breathing apparatus. They are incapacitated within seconds. A third person follows. Three people are now casualties where there was initially one. No rescue attempt should be made without proper equipment — no matter how urgent the situation appears.

What the New IMO Resolution MSC.581(110) Requires

• Enclosed space entry permits now carry a maximum validity of 8 hours — ensuring atmospheric conditions are current
• CO2 is now explicitly included in mandatory atmospheric testing alongside O2 and CO
• Team-based entry is mandatory — single-person entry is explicitly prohibited
• A formal Enclosed Space Emergency Response Plan is required
• Expanded guidance on cargo-related atmospheric hazards — particularly bulk cargo

Before You Enter Any Enclosed Space

• A permit to work has been issued and signed by the responsible officer
• The atmosphere has been tested with calibrated equipment for O2, CO, CO2, and any cargo-specific hazardous gases
• The space has been ventilated and atmosphere retested before entry
• A trained standby person is in position at the entry point with communication and rescue equipment
• Rescue equipment — SCBA, lifelines, rescue harness — is immediately available at the entry point
• The permit is valid (maximum 8 hours) and covers the current conditions
• All crew involved know the emergency response plan and have rehearsed it

This week, do three things. Find every enclosed space on your vessel and confirm each one is signed and labelled. Test your atmosphere monitoring equipment and verify the calibration is current. Run a genuine enclosed space rescue drill — timed, procedural, with your crew acting out every step. Time how long it takes to get rescue equipment to the entry point. You may be surprised. That surprise is better experienced in a drill than in an emergency.

Related Reading

• Working at Height in Cargo Holds — confined spaces and fatal fall investigation findings
• Safe Harbour — how to report an unsafe enclosed space entry procedure
• Fire Hazard Prevention CIC 2026 — PSC will check enclosed space drill records and crew knowledge
• Engine Room Emergency Response — engine room bilges and voids are classified enclosed spaces
• CHIRP Annual Digest — enclosed space incidents are consistently among the most reported hazards