More than a dozen people were displaced Monday night after a carbon monoxide leak, Beloit fire officials said. Crews were called around 9:20 p.m. to 725 Vine St. for a leak in a three-unit rental building, according to a release. No one was injured or had any illnesses from the incident because of early detection by a carbon monoxide alarm, officials said. The leak displaced three adults and two children who lived at the address, as well as nine adults and six children who were visiting, according to the release. The heat exchanger in the boiler that heated all three units was found to be malfunctioning, investigators said.