(WSB photos)

FIRST REPORT, 2:38 AM: Big Seattle Fire response to a commercial building in the 6900 block of West Marginal Way SW [map]. What we’ve heard via scanner so far is that it “came in as an automatic fire alarm” and then some kind of heat/fire was found inside. We’re on our way.

2:45 AM: Still en route, but hearing via scanner that what firefighters are describing as a “small fire” is “under control.”

2:52 AM: We’ve just arrived in the area. West Marginal is completely blocked by fire equipment and police just south of the bottom of the Highland Park Way hill. We’ve parked as close as we can get and our photographer is heading to the scene on foot from here.

3:08 AM: Some of the units are being dismissed; SFD’s investigator is on the way. Some of the discussion has mentioned marijuana growing inside the building, and city and state records indicate that it was remodeled earlier this year to be a licensed “urban farm.”

(The building is the former HQ of United States Seafoods, which moved to Lake Union more than a year ago, though its signage is still on this building, as you can see in the photo above.)

3:33 AM: We’ve talked with the SFD public-information officer battalion chief on scene. (Added: video of the quick briefing.)

The fire was in a small room, contained, and extinguished.

SFD crews will stay here for a while on fire watch; the cause remains under investigation. No injuries.

4:06 AM: West Marginal is reopening both ways.

1:33 PM: SFD says an “overheated electrical installation” was to blame for the fire.