The Plasco Building — the Unfireproofed Skyscraper That Fire Pancaked, Killing 16 Firefighters

The Plasco Building, a 17-storey steel-framed high-rise on Jomhuri Avenue in central Tehran, collapsed completely on the morning of 19 January 2017, roughly three and a half hours into an uncontrolled fire, killing 16 firefighters and bringing the total death toll to about 22. The proximate cause was not the fire itself but what the fire did to bare steel: the building’s columns, trusses and beam-to-column connections carried no fire-resistive coating of any kind, so sustained temperatures above 600 degrees Celsius stripped roughly half the yield strength out of the load-bearing frame and triggered a fire-induced progressive collapse.

This was the first Iranian high-rise to be destroyed by fire-weakened steel, and it failed in the manner forensic engineers most fear: not a localized burnout, but a disproportionate, pancaking collapse in which the loss of a few upper-floor connections cascaded the entire structure to the ground in seconds. The north face buckled first, then the rest followed within moments, burying the firefighting companies that had entered the building on the assurance that it had been evacuated.

Built in 1962 by industrialist Habib Elghanian and named for his Plasco plastics company, the tower was once the tallest building in Iran and a symbol of pre-revolution modernization. By 2017 it had become a vertical garment bazaar: a ground-floor shopping arcade beneath a stack of unsprinklered clothing workshops packed with textiles, foam and combustible stock — an extreme fire load wrapped around an unprotected steel skeleton.

The government’s April 2017 report did not blame chance. It found that the Mostazafan (Bonyad) Foundation, which managed the building, had ignored repeated written warnings about its fire safety, and that government ministries had failed to enforce 22 separate national building regulations. The Plasco Building is now the textbook case for what an unfireproofed, unsprinklered steel high-rise does when it burns long enough: it does not merely gut — it disappears.

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