A fire at a building under construction in Brussels, Belgium, killed six workers. The cause and precise sequence are under investigation.

Brussels, dense with EU institutions, sees constant office construction and renovation.

Why buildings under construction burn

Finished buildings have fire compartments, sprinklers, emergency stairs and exit lighting that work. During construction, those systems are not yet installed or are being commissioned—while every condition for ignition is present: welding sparks, combustible insulation, paints and solvents, temporary wiring.

Workers often do not know the floor layout fully, and temporary stairs are narrow and dark. Once smoke fills a shaft, finding a way out is hard.

A recurring pattern

Multiple-fatality construction fires recur across Asia as well as Europe. The factors cited are consistent: combustible materials, weak control of hot work, and inadequate temporary escape routes.

Determining the cause in Brussels will take time. Belgian authorities plan to examine compliance with labor-safety rules.

Little is yet known about the six who died. European building sites employ many migrant workers from multiple countries, and observers have long noted that language barriers create blind spots in safety training. The same problem exists on construction sites in Korea and Taiwan.