TAIPEI (Taiwan News) — Keelung’s Fire Department said it will investigate the cause of a Wednesday night apartment fire that killed two people, including a firefighter who died after giving his breathing mask to a trapped woman who also died.

CNA reported the fire broke out around 10 p.m. in a second-floor unit of a six-story residential building on Leli 3rd Street, with thick smoke quickly filling the structure. Fire crews rushed to the scene after reports said a 34-year-old woman surnamed Lo (羅) was trapped inside.

Fire officials said the apartment was packed with clutter, which slowed rescue efforts and made it difficult for firefighters to move, according to Liberty Times. Crews were forced to rotate in and out to replace air tanks as they searched the smoke-filled rooms, per EBC News.

Keelung Fire Department Renai Fire Station Squad Leader Chan Neng-chieh (詹能傑) reentered the building for a third time after changing his air supply and found the woman pinned under debris and barely breathing. He removed his own breathing mask and put it on her in a final effort to keep her alive before collapsing from smoke inhalation, per UDN.

Rescuers later found Chan inside the apartment shortly before 2 a.m. and rushed him to a hospital, where he was pronounced dead. The woman was pulled out around 5:40 a.m. with no signs of life and was also pronounced dead after hospital treatment.

Fire officials said the blaze left two people dead, one person with minor injuries, and three others taken to a hospital as a precaution. Keelung’s Fire Department is working to determine whether the clutter inside the unit affected how quickly the fire spread, per The News Lens.

National Fire Agency statistics show 31 firefighters have died in the line of duty over the past decade, per CNA. Keelung Mayor Hsieh Kuo-liang (謝國樑) said he will seek the highest possible compensation and push for Chan to be honored at the Martyrs’ Shrine.