 There are no clear indications that europium is particularly toxic compared to other heavy metals . Europium chloride , nitrate and oxide have been tested for toxicity : europium chloride shows an acute <unk> LD50 toxicity of 550 mg / kg and the acute oral LD50 toxicity is 5000 mg / kg . Europium nitrate shows a slightly higher <unk> LD50 toxicity of 320 mg / kg , while the oral toxicity is above 5000 mg / kg . The metal dust presents a fire and explosion hazard . 
