What must be done if oxygen deficiency occurs 19.5 percent during a permit required confined space entry?

If oxygen deficiency occurs (below 19.5%) during a permit required confined space entry, the following steps must be taken:

1. Immediately evacuate all personnel from the confined space.

2. Ventilate the confined space until the oxygen level is at least 23.5%.

3. Re-enter the confined space using a supplied air respirator or a self-contained breathing apparatus (SCBA).

4. Continue to monitor the oxygen level in the confined space and evacuate all personnel if it falls below 19.5% again.

Oxygen deficiency is a serious hazard in confined spaces, as it can lead to unconsciousness and death. It is important to take all necessary precautions to prevent oxygen deficiency from occurring, and to be prepared to respond appropriately if it does occur.