The story
Founded by François Raynaud and Émile Raynaud in 1892.1
On Wednesday, 29 April 1942, an enormous explosion of ammonium nitrate destroyed the entire Produits Chimiques de Tessenderloo factory and much of the surrounding town of Tessenderlo. In the incident, 189 people died and more than 900 were injured. The factory was later rebuilt in the same place, a very controversial decision.
In 2015, Tessenderlo merged with Picanol.
From Wikipedia’s article on Tessenderlo Group, shared under CC BY-SA 4.0.6