In Canada, the Occupational Health and Safety regulations for confined space entry are outlined in the Canada Occupational Health and Safety Regulations (SOR/86-304). Here are the key requirements:

1. Identification and Assessment: Employers must identify confined spaces and determine if they are hazardous. A qualified person must assess the hazards associated with the confined space and specify necessary tests to ensure safety [1].

2. Atmospheric Testing: Before entry, the atmosphere inside the confined space must be tested to ensure it is safe. Continuous monitoring is required if the atmosphere could change during occupancy [2].

3. Ventilation and Oxygen Levels: The oxygen level must be between 19.5% and 23% by volume. If ventilation is used to maintain safe conditions, it must be equipped with an alarm or monitored by an employee [3].

4. Entry Permit System: If required, an entry permit system must be in place, specifying the duration of the permit and recording the names and times of entry and exit [2].

5. Training and Instruction: Employees must receive training on entry procedures, emergency procedures, and the use of protective equipment before entering a confined space [3].

6. Emergency Procedures: Employers must establish emergency procedures, including a plan for immediate evacuation if conditions change or an alarm is activated [4].

7. Protective Equipment: Appropriate protective and emergency equipment must be provided to employees entering the confined space and those involved in rescue operations [5].

8. Communication and Monitoring: A qualified person must be present outside the confined space to maintain communication with those inside and to summon assistance if needed [6].

These regulations are designed to ensure the safety of workers entering confined spaces by addressing potential hazards and ensuring proper procedures and equipment are in place.