The cause of the blast, which took place during work on a pipeline around 0930 GMT, is unknown, BASF said in a news release.
"There is visible smoke. Residents in the affected areas of Ludwigshafen and Mannheim have been asked to stay indoors and to keep doors and windows shut," BASF said.
Authorities have been informed, and further information will follow, BASF added.
(www.marketwatch.com)
