Several people have been injured while some are missing after blasts at two German chemical plants owned by BASF.
The incidents have forced the company to shut down some production facilities.
It’s understood there was an explosion and a fire which broke during work on pipelines in the north harbour area of its Ludwigshafen site.
In a statement BASF said it is investigating the cause of the explosion and is shutting down its two steam crackers.
Residents in Ludwigshafen have also been advised to avoid going outside and to keep their windows and doors shut.
The Ludwigshafen site is the largest chemical complex and covers and area of four square miles.
It employs 39,000 workers.
Four people were also injured in an earlier gas explosion at BASF’s Lampertheim facility.