Illegal fireworks sparked a blaze that torched a fourplex last week in Northeast Portland, investigators have determined.

Lt. Rich Chatman, a Portland Fire & Rescue spokesman, said investigators don’t know who lit the fireworks that burned the residential building in the 3900 block of Northeast Garfield Avenue early Friday.

Investigators also don’t know whether the person who ignited the three-alarm blaze intended to harm the building or the 10 people who were inside when the fire started, Chatman said.

Two people were taken to hospitals, Chatman said. One of them suffered critical injuries.

They’re among a number of people who were treated for fireworks-related injuries at Portland-area hospitals last week.

Five people — including at least one who jumped from a window to evade the Northeast Portland blaze — were treated for such injuries at Legacy Emanuel Medical Center’s trauma center.

Another five, including a child, were also treated for minor fireworks-related injuries at Providence St. Vincent Medical Center.

Investigators ask anyone who heard or saw fireworks near the Northeast Portland fourplex early Friday morning to call 503-823-4636.

Firefighters initially responded to the blaze about 3:40 a.m.

-- Jim Ryan; jryan@oregonian.com; 503-221-8005; @Jimryan015

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