Bulletin No.: 04/1994

Date (Y-M-D): 1994-03-28

Subject: Entry into Confined Spaces

1. Entry of persons into confined or enclosed spaces continues to cause injuries and fatalities on Canadian ships. Confined spaces are defined in the Marine Occupational Safety and Health Regulations as a "storage tank, ballast tank, pump room, coffer dam (sic) or other enclosure, other than a hold, not designed or intended for human occupancy, except for the purpose of performing work,

1. hat has poor ventilation,
2. in which there may be an oxygen deficient atmosphere, or
3. in which there may be an airborne hazardous substance."

Holds that have not been properly ventilated can also contain a hazardous atmosphere.

2. In a recent case, two workers entered the ballast tank of a barge to determine if it could be outfitted with a bilge pump. When they passed out, a first aid attendant was called who subsequently entered the tank with a portable oxygen bottle and mask. The attendant was also overcome. The municipal fire department eventually removed the three victims but the first aid attendant died. When the ballast tank was tested, it had only 13% oxygen and 58ppm of carbon monoxide. The normal oxygen level is 21% and 18% is considered to be the minimum acceptable level.

3. Materials like rusting steel, wood, as well as vegetable products, fish, and many ores can use up the oxygen in a space without ventilation. When a person enters a space that does not contain an adequate supply of oxygen, they can pass out before they realize that something is wrong. The human body determines the need to breathe from the level of carbon dioxide in the lungs; the body cannot detect a lack of oxygen. Toxic gases that may also be present often do not have a detectible odour.

4. Both the Marine Occupational Safety and Health Regulations and the Safe Working Practices Regulations contain requirements for entering confined or enclosed spaces. The Safe Working Practices Regulations require that "No person shall enter a pump room, cofferdam, ballast tank, oil tank or similar compartment unless he is wearing a breathing apparatus." There are exceptions for areas that have been tested and found safe. Ship Safety Bulletin 15/91 contains an extract of the IMO "Code of Safe Practice for Solid Bulk Cargoes " that explains the risks and safety precautions related to an enclosed space.

5. The Ship Safety Branch provides a plastic warning notice, in both official languages to help educate persons working on board ships of this danger. The poster is 53cm x 41cm and its stock number is 7690-21-TXB-0003. A reduced version of the poster is attached to this bulletin. It is available from regional offices of the Ship Safety Branch. The notice should be placed in strategic places on board ships such as mess rooms and engine rooms and in longshoremen's canteens and changing rooms.

6. All persons who may have any reason to enter any enclosed space on a ship should familiarize themselves with the hazards and proper procedures for working in this specialized environment.

To add or change your address, contact us at: marinesafety@tc.gc.ca

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