Abstract: A mobile enclosure unit for containment of contaminants has a vertical, wheeled frame assembly having an open upper end and a lower wall. The frame assembly is adjustable in height so that the open upper end can be positioned in contact with a ceiling, allowing access for workers to work on or in the ceiling. A pliable cover sleeve surrounds the frame assembly from the upper end to the lower wall to form a chamber within the frame assembly having an open upper end to allow a worker in the chamber to access the ceiling area above the open end of the unit. An exhaust system is mounted in the frame inside the sleeve for drawing in air from the chamber, filtering debris from the air, and exhausting filtered air from the chamber.