Residents have been permitted to return to their apartments after the CO levels have returned to safe levels.
Heat also has been restored to the apartments, however crews were still working to restore heat to the central hallways.
The CO detectors that alerted firefighters to the high levels started being used by the department at the end of December.
Firefighters said without those detectors, the situation at the apartment complex could have been much worse.
Firefighters responding to a resident who fell at a senior citizen apartment high rise on East High Street discovered high levels of carbon monoxide, forcing the evacuation of approximately 130 residents, according to the Springfield Fire Division.
The incident was reported at the Springfield Towers apartments around 7:10 a.m. in the 300 block of East High.