The fire is burning at the Cinnamon Ridge Apartments in the 6500 block of Spencer Highway.
From SkyEye HD, flames could be seen shooting out through the roof of one building at the complex, and Pasadena officials say there's been a partial roof collapse.
We're told a couple of people had to be treated on scene for smoke inhalation, but no other injuries were reported.
In 2010, the same apartment complex erupted in flames and displaced residents in 12 units.
No other details were immediately available.
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