Ashley Cole

KSDK-TV, St. Louis

ST. LOUIS — Three people are dead and four others are injured after a boiler exploded in St. Louis on Monday, according to the fire department.

Officials said a boiler exploded at Loy-Lange Box Co. in the Soulard neigborhood, sending the boiler airborne and through the roof of a nearby building. The boiler is about the size of a full-size van.

The injured were taken to the hospital with two in critical condition and two in serious condition, the St. Louis Fire Department said.

St. Louis Fire Chief Dennis Jenkerson said one person was killed when a boiler exploded at a box company. It then flew about 500 feet before crashing through the roof of a nearby laundry business, killing two more, he said.

A third person at Faultless Healthcare Linen was pinned under the boiler but fire department responders were able to free that victim.

At least three buildings in the area were affected.

Jenkerson said the boiler was a cast iron cylinder about 8 or 9 feet long and 4 feet in diameter, weighing about 1½ tons.

Jenkerson told the St. Louis Post-Dispatch that the explosion seems to have been accidental and that investigators will review machine maintenance records.

No other details have been released, including whether anyone was working on the boiler at the time of the explosion.

The company is described on its website as a "full service corrugator and custom box manufacturer."

Contributing: The Associated Press. Follow Ashley Cole on Twitter: @AshleyColeKSDK