Blast Effects

Blast struck downward against the roof of the Chinzei school, 1,500 feet from ground zero at Nagasaki, Japan, which had been taken over in part for munitions work. The fourth story collapsed completely, but the heavy earthquake-resistant structure protected some machine tools on the first floor from serious damage. Electric transformers and a switchboard did not escape; a combination of blast, fire and debris destroyed them.

Source: National Archives