Dive Brief:

• A six-story San Francisco apartment building being constructed as part of a 360-unit complex by BRE Properties was destroyed by a fast-moving fire that broke into the open about an hour after most workers had knocked off for the day Tuesday.
• City fire officials, who called five alarms to battle intense blaze, said the fire and the huge volumes of water being poured on it likely would collapse the 80-foot building on Fourth Street.
• The intensity of the flames, which burst out after smoldering for what Fire Chief Joanne Hayes-White said might have been an hour, melted scaffolding. A crane operator who was 228 feet up over another building said he could feel the heat in his cab. 

Dive Insight:

Fire investigators had not yet determined the cause of the fire. Firefighters continued to pour water Tuesday night onto what one described as a "volcano" formed by upper floors collapsing. There are numerous projects underway in the area, and reports said the first fire truck responding to the scene had trouble getting through the clogged streets.