Specialized equipment designed to process aluminum oxide in lengths of nearly 50 feet caught fire Thursday morning at a sintering plant in Ludwigshafen, Germany.

Sintering is the process of compacting and forming a solid mass of material by heat or pressure without melting it.

The Ludwigshafen Fire Brigade responded to an automatic alarm from Almatis GmbH, a factory specializing in high quality materials used in the refractory, ceramic and polishing industries. Firefighters arrived to find that heavy oil had escaped from equipment and ignited.

“The fast-moving extinguishing measures prevented further damage spread,” according to the Ludwigshafen Fire Brigade.

Two workers missing after the fire were located, one of whom was injured in a fall.

The sintering unit has been shut down until the cause of the explosion is determined and other safety checks conducted. Other portions of the factory continued to operate.