ESSEN, GERMANY (April 3, 7:15 a.m. ET) — An Evonik Industries AG employee has died and another was seriously injured in an explosion and fire at the company’s Marl facility in Germany. The cause of the explosion, which happened March 31, is not yet known.

The incident happened in the cyclododecatriene (CDT) plant at the Marl facility. Local fire services extinguished the fire after a few hours.

In a statement, Essen-based Evonik said it did not have further information on the condition of the injured employee, who was taken to hospital by helicopter.

Klaus Engel, chairman of Evonik, expressed the company’s sympathy for the employees and their families.

A spokesman for Evonik said the company has not been allowed access to the site while local authorities conduct their investigation. For that reason, Evonik is not able to assess the damage to the CDT plant.

CDT is a raw material for production of flame retardants and also a starter chemical used in the process to make polyamide 12.