What can be assumed to result in the highest up-front cost to address a lead dust hazard?

The action that results in the highest up-front cost to address a lead dust hazard is paint removal or component replacement. This is because this option involves the physical removal of lead-based paint from surfaces, which typically requires specialized labor, specialized equipment, and safe disposal procedures to adhere to regulations. The process can be labor-intensive and may necessitate extensive safety measures to protect workers and occupants from exposure to lead dust during the removal process.

In contrast, encapsulation, sealing, and enclosure tend to be less costly because they involve methods that manage or contain the hazard rather than removing it entirely. Encapsulation involves coating the lead-based paint with a protective layer that seals it, while sealing involves applying materials to prevent dust from becoming airborne. Enclosure includes constructing barriers around the lead hazard, which does not require the direct removal of hazardous materials. All of these options, while effective in managing lead hazards, do not involve the same level of direct labor and material costs associated with complete removal.