Columbia, PA – Two children were taken to the hospital after what was first believed to be a gas leak in Columbia on Sunday morning, emergency officials said.

Some 40 Columbia firefighters responded to the scene of the 11:39 a.m. leak, a house at 341 N. Second St. in the borough.

According to Columbia Fire Chief Scott Ryno, officials instantly determined there was “a large concentration of gas and a large concentration of CO (carbon monoxide) in the residence.”

The two children, whose names and ages were not given, were found unconscious at the scene, Ryno said.

They then were transported by advanced life support to the hospital, the Columbia chief said.

An attached residence at 343 N. Second St., where no one was home at the time, also had “residual gas and CO at that unit,” Ryno said.

Emergency crews secured the gas, or turned it off, and spent an hour ventilating both residences while crews from UGI were arriving at the scene.

“We had to take the precaution that we did” with the uncertainty over the nature of the incident, Ryno added.

UGI spokesman Joe Swope said later Sunday that there was no gas leak and that the problem was traced to a faulty furnace.