The Occupational Safety and Health Administration (OSHA) has specific requirements for confined space entry to ensure worker safety. These requirements are outlined in OSHA's standard 29 CFR 1910.146 for Permit-Required Confined Spaces. Key requirements include:

1. Identification and Evaluation: Employers must identify and evaluate all confined spaces in the workplace 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 exit. This training should be provided to all employees who may enter confined spaces, as well as those who may assist in rescue operations.

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: Adequate ventilation must be provided to ensure a safe atmosphere within the confined space.

6. Rescue and Emergency Services: Employers must have a plan for rescue and emergency services, which may include on-site rescue teams or arrangements with local emergency services.

7. Communication: Continuous communication must be maintained between the workers inside the confined space and the attendant outside to monitor the safety of the entrants.

8. Signage and Barricades: Confined spaces should be clearly marked with signs and barricades to prevent unauthorized entry.

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.