During the final visual inspection, the AMS must check for visible dust and debris behind what?

The final visual inspection is a crucial step in the asbestos abatement process, where the Asbestos Management Supervisor (AMS) must ensure that the area is free from any visible contamination that could pose a health risk. The correct choice emphasizes the importance of checking behind all critical barriers.

Critical barriers are physical structures designed to contain asbestos fibers within a work area, preventing the spread of contamination. These barriers, which can include plastic sheeting, walls, or other enclosures, are essential for protecting both the workers involved in the abatement process and the surrounding environment. Any dust or debris found behind these barriers may indicate a failure in the containment measures and could lead to potential exposure during or after the abatement process. Thus, it is vital for the AMS to monitor these areas closely.

In contrast, while issues like exposed insulation, frayed electrical wires, and areas with active construction may present certain risks, they do not specifically address the need to ensure that asbestos fibers are contained within critical barriers. Therefore, focusing on the barriers provides a more direct approach to safeguarding public health and maintaining compliance with asbestos regulations.