Complex sentence: The chemical claimed the lives of roughly one million people in gas chambers installed in extermination camps at Auschwitz-Birkenau, Majdanek, and elsewhere.Half of the victims were Jews, and by far the majority killed using this method died at Auschwitz.
Split into simpler sentences: The chemical claimed the lives of roughly one million people in gas chambers installed in extermination camps at Auschwitz-Birkenau, Majdanek, and elsewhere. Most of the victims were Jews, and by far the majority killed using this method died at Auschwitz.