Arson is a big problem for construction sites in Oakland.
Housing developers in the East bay have ramped up security came after a series of arsons and unexplained blazesover the last several years.
A security team was stationed at the City Ventures site at all times and up to 15 security cameras were live-streaming when the fire occurred, officials said.
The Jobs and Housing Coalition, a lobbying group of Oakland developers and businesses, said in July that members have quadrupled their spending on security since the blazes that occurred at developments in Oakland, Emeryville and Concord.
Construction sites were equipped with video cameras, fencing, alarms, bright lights and 24-hour security guards. Some developers have also started using fire-retardant products, the coalition said.