Crews have cleaned up a chemical spill in Waterloo that sent a man to the hospital. The accident happened at the Waterloo Water Works around 4 p.m. yesterday. Waterloo fire rescue officials say the driver of a chemical truck spilled a mixture of chlorine and fluoride. He ended up in the hospital after inhaling vapors from a mild gas that developed when the chemicals mixed together. The man’s identity and his condition haven’t been released. Firefighters called to the scene quickly dissolved the vapors, using water. During the operation, emergency crews took additional precautions by closing off two city streets and ordering nearby residents to stay in their homes. The chemical spill happened next to an elementary school, but classes there had already dismissed for the day. A Des Moines company owns the chemical truck involved in the accident. The company sent a crew to Waterloo last night to clean up the spill.