An abatement technique that utilizes a rigid material, mechanically affixed and dust tight, to control a lead hazard is called: ______ .

The technique referred to involves using a rigid material that is mechanically affixed in a way that ensures it is dust tight. This method is known as enclosure, and it is specifically designed to isolate and contain lead hazards by enclosing them within a solid barrier, thereby preventing access to and contact with the lead-based materials.

Enclosure is particularly effective because it not only addresses the immediate hazard but also allows areas with lead-contaminated surfaces to remain undisturbed while ensuring safety for occupants. The method must create a complete barrier that prevents the release of lead dust into the environment, which is why it must be both mechanically secured and sealed properly.

The other methods listed, such as sealing and encapsulation, have different applications and characteristics. Sealing often involves filling cracks or gaps to minimize lead dust dispersion, while encapsulation entails applying a specific coating to the surface of lead paint to prevent exposure, rather than creating a physical barrier around the hazard. Containment generally refers to temporary measures to control lead dust during remediation activities rather than a permanent solution like enclosure.