Which layer must be placed on the floor in the work area?

The correct choice is 6mil plastic because it provides an optimal balance between durability and effectiveness in containing asbestos fibers that may be disturbed during removal or repair operations. The thickness of the plastic is significant as it acts as a barrier to prevent asbestos contamination from spreading into surrounding areas.

A 6mil layer is robust enough to resist tears and punctures that can occur in a work environment where heavy materials might be moved around. Additionally, it meets regulatory requirements for asbestos abatement projects, ensuring compliance with safety guidelines that protect workers as well as the environment. Using thicker plastic, like 8mil, may be overkill and unnecessary, while thinner options like 4mil or 2mil may not offer sufficient protection against potential hazards associated with asbestos work. Therefore, 6mil plastic is the recommended standard in asbestos abatement for floor coverings, ensuring both safety and reliability in the containment of hazardous materials.