9:11 AM: In case you’re wondering about the big fire response headed for Harbor Island, they’re checking out a possible fire at a business in the 3400 block of 13th SW. The first unit on the scene reports “light smoke” coming from a metal building. More as we get it.

9:16 AM: The fire has been “knocked down,” per scanner. But there’s word a firefighter has been hurt.

9:42 AM: More reinforcements have been called to the fire scene, including ventilation. No official update yet about the injured firefighter, but SFD’s public-information officer was headed to the scene too, so we should have word soon. The SFD response is right by the entrance to Harbor Island when you leave the low bridge and circle around on Klickitat, so avoid the area if you can.

9:47 AM: Update from SFD’s Kyle Moore – A firefighter in his 30s has been taken to Harborview with second-degree leg burns after stepping into what turned out to be (updated) boiling water or metal; also, a worker in his 30s was “splattered with materials” and will be taken by private ambulance to be checked out further. (There was concern earlier about “volatile” materials in the furnace.)

9:56 AM: The fire is now described as “tapped.” Some units are being dismissed from the scene.

10:44 AM: We’ve added two more photos as well as video of what Moore told us at the scene – the photo above this line shows the MVU (mobile ventilation unit) he mentioned.

ADDED 2:24 PM: SFD has just published a full update on its website. The firefighter who was hurt suffered 1st- and 2nd-degree burns, SFD’s update says, and will be moved overnight to the Harborview burn it; he’s been with the department since 2006 and is based at North Delridge’s Station 36. What happened to him is explained as:

The firefighter manning a hose line in the smoky building stepped into a two-foot deep slag pit that is designed to catch molten metal. The unmarked and unsecured pit was full of boiling water. The boiling water made its way into the firefighter’s boots causing 1st and 2nd degree burns to his lower legs. A Mayday was called and fellow firefighters quickly rescued the injured co-worker.

The injured worker who suffered “spot burns” is described as in stable condition. And investigators say the fire “was accidental, caused by a failure in the induction furnace,” with damage estimated at $85,000.