A gas line exploded Thursday at the shuttered Entergy power plant in the Michoud area in New Orleans East, injuring eight people, one of them seriously, authorities said.

The call about a one-alarm blaze went out at 1:13 p.m., and the New Orleans Fire Department arrived at 1:20 p.m. to find a man buried in a hole 10 feet deep.

Firefighters immediately began digging the victim out by hand as he lay face down in the mud and clay, providing him with oxygen once his head and torso were freed.

The man, who was not identified beyond being an Entergy employee, was rescued after about an hour and evacuated by medical helicopter to a hospital.

Seven other Entergy workers were treated for minor to moderate injuries. One was treated and released on the scene, with the other six taken to the hospital, a Fire Department spokesman said.

The explosion occurred when a piece of construction equipment struck a 20-inch gas line at the Entergy plant.

New Orleans Emergency Medical Services, the Police Department, the New Orleans Office of Homeland Security and Emergency Preparedness and the State Police also responded to the incident.

State Police and Entergy are investigating the cause of the accident.

The company, which is in the process of replacing the 1960s-era Michoud facility, did not return calls for comment. 

Follow Chad Calder on Twitter, @Chad_Calder.