Which of the following must be present to enter and work in a confined space?

To safely enter and work in a confined space, it is essential to have both an attendant present and proper ventilation. The presence of an attendant is critical because it ensures that someone is monitoring the work being done and is prepared to respond in emergencies. The attendant can also help communicate between the workers inside and those outside, facilitating a better understanding of any risks that may arise during the operation.

Ventilation is equally important as it helps to maintain safe air quality within the confined space. It ensures that any hazardous gases, vapors, or lack of oxygen are managed effectively. Proper ventilation can significantly reduce the risks associated with working in confined spaces, where atmospheric conditions can change rapidly and become dangerous.

Work gloves, a hard hat, and a participation certificate are important safety measures in various contexts but do not specifically address the unique hazards associated with confined spaces. While personal protective equipment like gloves and hard hats may be necessary in some environments, they do not substitute for the fundamental safety measures required for confined space entry, which focus on monitoring and air quality control.