Train cars leaked corrosive hydrochloric acid after a Saturday derailment . The spill caused a toxic cloud to form above Lafayette site . Residents outside the evacuation area were advised to close windows and doors and turn off air conditioning to avoid any contamination . Exposure to the cloud can irritate people . Local authorities evacuated about 3,500 homes and businesses .
Train cars leaked corrosive hydrochloric acid after a Saturday derailment . The spill caused a toxic cloud to form above Lafayette site . Exposure to the cloud can irritate people . Local authorities evacuated about 3,500 homes and businesses .