Pennsylvania state police are investigating how a woman became trapped in a drainpipe at a closed power plant.

Emergency crews in Greene County were called to FirstEnergy's now-shuttered Hatfield Power Plant in Carmichaels on Monday morning.

Trooper Forrest Allison says a worker was about to drain a pond on the property into the nearby Monongahela (muh-NAHN'-guh-hee-luh) River when he heard the woman shouting from the drainpipe below.

Allison says "if he had turned on the valves, all the water would have rushed to where she was."

Crews helped the 39-year-old Greene County resident out. She was taken to a hospital for treatment of unspecified injuries.

Allison says it's unclear how the woman ended up in the pipe, and police are investigating.