A detonation occurred during the treatment of residual acids from the production of explosive oils. These residual acids from nitrated oil fabrication were then transferred to the nitrogen removal installations via an aboveground 120-m long pipe.

On the day of the accident, the outdoor temperature was near the -15°C mark, thereby blocking the flow of fouled nitroglycerin and nitroglycol acids inside the pipeline. A maintenance team undertook the task of “defrosting” the pipe by heating it through the use of open flame devices and through disassembling some selected parts, which in turn caused a detonation. A technician died and several metres of pipe were destroyed.

The explosion took place on a portion of the pipe that had not yet been heated and where the victim was not equipped with either a heating device or any special tool. The reheating and disassembly of the frozen pipe was able to generate thermal and mechanical stresses on the stagnant and frozen explosive oil, thus causing a autocatalytic chemical decomposition of nitroglycerin.

The operating safety range of the installation was revised on the basis of temperature in order to safeguard against special risks related to periods of intense cold weather. The residual nitration acid transfer pipeline was heated to above the freezing point.