What must be done before entering excavations over 4' in depth where oxygen deficiency is possible?

Before entering excavations over 4 feet in depth where oxygen deficiency is possible, it is essential to test the atmosphere. This action is critical to ensure the safety of individuals working in such environments.

Testing the atmosphere allows workers to assess the levels of oxygen and identify the presence of any hazardous gases. Oxygen levels below 19.5% are considered dangerous, and specific poisonous gases can lead to life-threatening situations. By accurately testing the atmosphere, workers can make informed decisions about the need for ventilation or other protective measures based on the results.

While providing ventilation, wearing protective gear, and using breathing apparatuses are all vital safety protocols for working in potentially hazardous conditions, they should be implemented based on the results of the atmospheric testing. Therefore, testing the atmosphere is the initial and most crucial step in ensuring safety before entering such excavations.