LEWISTON – Flames ripped through a downtown office Thursday afternoon, sending employees scurrying as smoke and fire filled three buildings at Ash and Lisbon streets.

The blaze at Financial Institutions Services Corp. appeared to have started in a bank of computer equipment on the second floor, fire investigators said.

However, the cause was not expected to be known until today, after environmental cleanup crews cleared ammonia and other chemicals from the fire scene.

About 2:30 p.m., fire and smoke filled a room at the back of the building. Flames shot out toward Park Street when firefighters smashed their way in.

No one was hurt when employees at FISC ran from the building and took refuge in a bank around the corner. The company processes an estimated 16 million checks a month, from loan payments to paychecks.

By nightfall, employees at the business were back at work on the first floor, processing checks for local banks. The impact of the fire for local people was expected to be minimal.

“We’re here, we’re working, we’re processing checks tonight,” said FISC President Carol Sabasteanski. “The fire did affect some of the systems but we’re recovering some of those systems. From a consumer standpoint, it doesn’t really affect them at all.”

Cathi Gonazalez had a perfect view of the fire scene from her office at Laskoff & Associates law firm on Park Street. When she looked outside about 2:30 p.m., Gonzalez said there were about four dozen people standing between the FISC building and Five County bank.

“I saw people outside by the bank; they were all looking up near the top of the building,” Gonzalez said. “I went out there to see what was going on and I saw black smoke coming out of the chimney. When the firefighters arrived, and opened the doors and broke some windows, it was then that I could see the flames.”

Firefighters made quick work of the fire, but smoke filled the FISC offices and three buildings attached to their headquarters.

At dark, foul-smelling smoke continued to float down an alley between Park and Lisbon streets, Public Library officials considered closing their building until the space was deemed safe by a fire official.

A handful of tenants who live in apartments attached to the FISC building also fled their homes as firefighters responded to the scene. There was no fire damage to those apartments, but smoke was seeping into the homes long after the flames were put down.

Those tenants were able to return to their apartments by supper time. Behind the fire scene, at Five County, customers continued pulling up to drive-up banking windows while fire crews worked nearby.

Hours after the fire was reported, emergency vehicles clogged the corners around the scene. A section of Lisbon Street was blocked off, as were parts of Ash and Park streets.

By 4 p.m., FISC employees were showing up for work, unaware that fire had damaged their place of employment. Fire investigators expected a long afternoon of hosing down hot spots and mopping up after the blaze.

“It’s going to be a long, long process,” said Fire Chief Michel Lajoie. “The building is filled with smoke, and there’s a lot of electronic equipment in there.”

After the flames were knocked down and crews prepared to enter the building, there were further problems. Chemicals inside the business had spilled or leaked, and environmental cleanup crews were called to the scene.

Fire inspector Paul Ouellette said workers from Clean Harbors were expected to finish the cleanup by this morning, when he would go inside and begin searching for the cause of the blaze.

FISC President Sabasteanski said the job of processing checks for local banks was set back by a few hours by the fire. However, she said backup equipment and emergency plans helped minimize the delays.

“I’m very impressed with how well the staff has fallen into their roles,” she said. “We’ll be a few hours late on some things, but there won’t be a huge impact on the consumers.”

The extent of damage was not known Thursday night. Computers, servers and wiring burned in the afternoon blaze.

“It was described to me as the heartbeat of the company,” Ouellette said.