The Department of Justice has filed a civil lawsuit against Norfolk Southern, accusing the U.S. railroad giant of violations of the Clean Water Act over the February 3 derailment of a freight train in East Palestine, Ohio. The disaster led to a massive explosion and the release of toxic chemicals, including levels of dioxin hundreds of times higher than what’s considered safe. Meanwhile, CNN reports seven U.S. government investigators briefly fell ill in early March while studying the possible health impacts of the disaster. The investigators with the Centers for Disease Control and Prevention reported sore throats, headaches, coughing and nausea.