OSHA's requirements for confined space entry are detailed in the standard 29 CFR 1910.146, which outlines the necessary practices and procedures to protect employees from the hazards of entering permit-required confined spaces. Key requirements include:

1. Permit-Required Confined Space Program: Employers must develop and implement a written program that includes measures to prevent unauthorized entry, identify and evaluate hazards, and establish safe entry operations [1].

2. Entry Permit System: A valid entry permit is required before entering a confined space. The permit must list authorized entrants, the purpose of entry, hazards, and measures to control those hazards [2].

3. Hazard Assessment: Employers must evaluate the workplace to determine if any spaces are permit-required confined spaces and inform employees of the hazards [3].

4. Training: Employees must be trained to understand the hazards and procedures for safe entry and work in confined spaces. This includes training for attendants and rescue personnel [2].

5. Atmospheric Testing: The atmosphere within the space must be tested for oxygen content, flammable gases, and toxic air contaminants before entry and periodically during entry [4].

6. Rescue and Emergency Services: Employers must provide rescue and emergency services, including equipment and trained personnel, to ensure prompt and safe rescue from confined spaces [5].

7. Communication and Monitoring: Continuous communication between entrants and attendants is required to ensure safety and facilitate emergency response if needed [2].

These requirements are designed to ensure that confined space entry is conducted safely, with appropriate precautions to protect workers from potential hazards.