Two employees first noticed light smoke on the seventh and eighth floors of the downtown library, located at 150 E. San Fernando St., at about 6:45 a.m., according to San Jose fire Capt. Scott Kouns.
Because the smoke was reported in a high-rise building, about 70 firefighters responded to the scene in the unlikely event evacuations were necessary, Kouns said. Crews checked each floor, from the basement to the roof and traced the smokes' origin to some eighth-floor mechanical equipment.
"There's no actual fire," he said. "The equipment is isolated and no electrical goes into it."
Crews left the library shortly after 8 a.m., according to Kouns.
The library will be open as normal today, according to spokeswoman Lorraine Oback.
