The Occupational Safety and Health Administration (OSHA) has specific requirements for confined space entry to ensure worker safety. These requirements are outlined in the OSHA standard 29 CFR 1910.146, which applies to permit-required confined spaces in general industry. Key requirements include:

1. Identification and Evaluation: Employers must identify and evaluate all confined spaces to determine if they are permit-required confined spaces.

2. Permit System: A written permit system must be implemented for entry into permit-required confined spaces. This includes specifying the entry conditions, the work to be performed, and the duration of the permit.

3. Training: Employees must be trained to understand the hazards of confined spaces and the procedures for safe entry and work. This includes training for authorized entrants, attendants, and entry supervisors.

4. Atmospheric Testing: Before entry, the atmosphere within the confined space must be tested for oxygen content, flammable gases and vapors, and potential toxic air contaminants.

5. Ventilation and Equipment: Appropriate ventilation and personal protective equipment (PPE) must be provided to ensure safe entry and work within the confined space.

6. Rescue and Emergency Services: Employers must develop and implement procedures for summoning rescue and emergency services, and ensure that rescue personnel are available and trained.

7. Communication: Continuous communication must be maintained between the entrants and the attendant to monitor the status of the entrants and to alert them of the need to evacuate the space if necessary.

These requirements are designed to protect workers from the hazards associated with confined spaces, such as toxic atmospheres, engulfment, and entrapment. Employers should ensure compliance with these standards to maintain a safe working environment.