Her reasons for suicide have been the subject of ongoing speculation. There were multiple stresses in the marriage, and it has been suggested that she opposed Haber's work in chemical warfare. According to this view, her suicide may have been in part a response to Haber's having personally overseen the first successful use of chlorine gas during the Second Battle of Ypres, resulting in over 67,000 casualties. Haber left within days for the Eastern Front to oversee gas release against the Russian Army. Originally buried in Dahlem, Clara's remains were later transferred at her husband's request to Basel, where she is buried next to him.