The fire department at Kitakyushu, Fukuoka Prefecture, admitted Wednesday that it was unaware an apartment building where a fire on Sunday claimed six lives was used for housing despite some of the victims having applied for welfare benefits through the same municipality.

The oversight by the fire department, which had not carried out any official fire alarm checks at the wooden, two-story complex, was revealed by city officials, exposing shortcomings in information sharing between municipal departments.

The occupants of the building's 16 apartments were mostly day laborers and some welfare recipients.