Transition Optical was a manufacturer of prescription quality photochromic glass lenses that progressively darkened in sunlight. In 1992, a fire occurred in one of the HVAC mechanical systems servicing some of their Cleanroom environments requiring a thorough decontamination of the structure, equipment, labs, and the Class 100 Cleanrooms. Of vital importance was the continuing operation of the manufacturing facility, specifically the other Cleanrooms not affected by the event. Critical airflow and filtration measures were employed to insure uninterrupted operation during the restoration project.