OVERLAND PARK, Kan. – A fire that leveled a multimillion-dollar apartment building under construction and spread to about two dozen homes in suburban Kansas City started when a welder accidentally ignited wooden building materials, fire officials said.

More than 100 firefighters battled the blaze at the CityPlace development in Overland Park on Monday and three were treated for minor injuries. The fire destroyed the four-story apartment building, heavily burned a second and rained burning debris onto a nearby neighborhood, damaging at least 22 other homes.

Overland Park Fire Chief Bryan Dehner said the building where the fire started was "most vulnerable" when the fire happened because it was so early in the construction process that it lacked fire deterrents such as a sprinkler system. A steady wind of 10 to 15 mph also played a role in the spread of the fire, said John Ham, a Kansas City spokesman for the Bureau of Alcohol, Tobacco, Firearms and Explosives.

Overland Park Fire Marshal Mark Sweany said Tuesday evening that a welder accidentally sparked the initial blaze.

Titan Built LLC, the construction company working on the apartment project, released a statement Tuesday expressing concern for the "health and welfare" of employees and surrounding neighbors.

"Titan Built has meticulous safety protocols in place; in our 42-year history, we have never experienced an incident such as this," the statement said. "We are closely working with the fire department and actively participating in the investigation to determine the cause, all toward implementing preventative processes in the future."