Enclosed Space Entry
Enclosed Space Entry is the tightly controlled procedure for entering a space on a ship that is not designed for continuous occupancy and may contain a hazardous atmosphere — cargo tanks, ballast tanks, cofferdams, chain lockers, void spaces and duct keels. Such spaces can be oxygen-deficient, or contain toxic or flammable gas, with no warning to the senses.
Entry is only made under a permit to work after the space has been ventilated and the atmosphere tested for oxygen, flammable and toxic gases, with a responsible person in charge, communication and rescue arrangements in place, and a standby person at the entrance. Enclosed-space accidents — often when would-be rescuers also collapse — remain one of the biggest causes of multiple deaths at sea, which is why SOLAS requires regular entry-and-rescue drills.
Enclosed spaces kill more seafarers than almost any other single hazard, frequently in twos and threes as rescuers rush in unprotected. The rigid entry procedure — test, ventilate, permit, standby, rescue plan — exists precisely because an invisible atmosphere gives no warning, and it is drilled under SOLAS for exactly that reason.
Why are enclosed-space entries so dangerous?
The atmosphere can be oxygen-deficient or contain toxic or flammable gas with no smell or visible sign, so a person can be overcome within seconds. Many deaths occur when untrained rescuers enter to help and are also overcome.