Final answer:
A second pair of shoe covers is required under USP 800 when entering the buffer or containment buffer area to prevent spread of contamination.
Step-by-step explanation:
Under USP 800 guidelines, a second pair of shoe covers must be donned when entering the buffer area or containment buffer area in facilities where hazardous drugs are prepared. This is a critical step to prevent contamination of clean areas and to ensure that any potential contamination does not spread outside of designated hazardous areas. After compounding activities are completed, the second pair of shoe covers should be removed immediately upon exiting the buffer area to prevent the spread of hazardous drug residues to other areas of the healthcare facility.