Dive Brief:

• Medical personnel took seven construction workers to hospitals to be treated for smoke inhalation after fire broke out Monday in a century-old hotel in San Francisco that was being renovated.
• They were working in the Renoir Hotel on Market Street when fire broke out about noon, officials said.
• Investigators were trying to figure out what started the fire in the 135-room hotel that its owner, The Kor Group, which said the 1909 structure was closed last year for the construction work.

Dive Insight:

It took firefighters about three hours to get the blaze under control. Firefighters took defensive positions outside of the building at one point when explosions -- possibly caused by propane tanks -- were heard inside, KTVU reported.The cause of the fire remains under investigation.