Upgrade and expansion of an existing Biosafety Level-3 (BSL-3) Laboratory located on the third floor of the California Department of General Services laboratory facility. Approximately 2,000 SF of existing laboratory space was demolished and replaced with a new BSL-3 laboratory. The new facility features three laboratories and one work room that has infrastructure in place to convert to a future fourth laboratory. It includes a staging area with freezer space and an autoclave, a decontamination room, a clean autoclave room, changing rooms, and valve room to house mechanical equipment. Rooftop scope covered removal and replacement of air handlers, filter bank, and exhaust fans, with associated structural, architectural, and waterproofing work. A great deal of coordination was required on this project as it took place within an operating building, and dealt with active systems of critical importance to adjacent laboratory rooms.