On March 19, 2016, twenty two children developed coughs, sore throats and other respiratory symptoms following exposure to chlorine at an indoor swimming pool located in Lafayette, Colorado. All 22 were seen in the emergency department. No one was hospitalized and no one died. Public health investigators determined that a chlorination valve stuck allowing more chlorine than needed to enter the system. During the daily monitoring done by staff on the day of the incident, the chlorine level doubled in a 3-hour period, rising from 3 ppm to 6 ppm.