WEYMOUTH (CBS) – Smoke inside the Dana-Farber Brigham and Women’s Cancer Center at South Shore Hospital forced all patients and staff to evacuate the building late Monday morning. The hospital said part of the HVAC unit malfunctioned, causing a smoke detector to go off.

There were approximately 50 patients and 75 staff members in the building at the time.

One Weymouth firefighter and a member of the engineering staff had to be treated for heat-related issues.

There is no word on when the building will reopen.