LEWISTON - A big blast and a lot of smoke. That's what many Lewiston residents heard and Lewiston firefighters saw Sunday morning, after an explosion and fire rocked the city's wastewater treatment plant in North Lewiston.

Firefighters say they heard the explosion and then around 7:45 a.m. received the call from two workers at the plant saying there was a fire in one of the control rooms.

"We heard an explosion, sounded awfully loud, so we all were looking around and anticipating," said Lewiston Fire Battalion Chief Kevin Kalbfleisch. "Sure enough, we got toned out to a structure fire after an explosion out at the wastewater treatment plant."

Fourteen personnel in three engines, three ambulances and a control vehicle were sent to the blaze. But, because of the condition of the building, they had to fight the fire from the outside.

"We were not going to send anybody inside the building because it obviously looked like it was compromised," said Kalbfleisch. "The walls were buckled and there was debris all over."

Firefighters were able to gain control of the fire in a half hour and had it completely put out within an hour.

Some Valley residents heard and felt the blast. Bob Brockman heard the blast from his home in the Lewiston Orchards and said it shook the ground.

"Just listening to the scanner and some church music," said Bob Brockman. "Then here a loud bang came."

Kim Bedwell was in his Clarkston home having coffee with his wife when he heard the blast and launched into action.

"Just relaxing, you know, before the day starts," said Bedwell. "And, all off a sudden, I heard this 'Kaboom!' And just, 'Boy, that was loud,' and she says, 'Well, I hope nobody got hurt.' So, anyway, she turned on the scanner and we heard somebody call for seven engines. So, that's when I grabbed my camera and batteries and headed out the door."

Bedwell went down to the levee by the railroad bridge to get footage of the inferno.

On Monday, the damage was being added up. In the building where the fire took place, the blast blew the doors off their hinges and buckled a wall, shooting debris for yards.

Lewiston Public Works Director Chris Davies is trying to piece it all together.

"Basically it's a control room for our digesters, which are basically two big tanks that this building is in between, these two big tanks," said Davies. "It basically controls the process of the digesters for those two things."

With all the damage, the city is looking at some serious money for repairs.

"We're looking, again, somewhere between three and five million," said Davies. "We don't know what the true value of it at this point. We're going to be looking at it in more detail as we go through this week and try and get a better number for that."

Davies says the plant is still open for business even though the impact from the blast caused significant damage to the building's foundation.

Fire investigators spent much of the day Monday searching for a cause.

"It's still under investigation," said Kalbfleisch.

Sewer plant fires are can be caused by a range of issues, from electrical issues to a build up of gasses.

"Investigators will look at all those options and try to see if they can pinpoint exactly what caused it, whether it was gas or some other electrical reason," said Kalbfleisch.

(All photos in this story are courtesy of the Lewiston Fire Department.)