Several TV news videos show part of the burning building collapsing.
 Updated at 6:40 p.m.
The fire  is a couple of blocks from  AT&T Park and includes office buildings, residential units and biotech. The call on the fire came just before 5 p.m. About 100 residents have been evacuated from a nearby residential building.
The buring construction site is a massive condo development that was supposed to be finished in a couple of  years.
The fire is snarling commute traffic, blocking streets that lead to freeways. Residents say the heat of the fire can be felt a block away.
Updated at 7:10 p.m.
Firefighters have made significant progress. No injuries have been reported.