The man was arrested for allegedly leaving a propane barbecue unattended.
RELATED: Residents urge Foster City to declare emergency following devastating condo complex fire
San Mateo County District Attorney Steve Wagstaffe said the investigation found the man had no intent of starting a fire.
Earlier this week, city officials decided not to declare a state of emergency because the fire happened on private property.
The fire in early August left about 150 people without a place to live.