Indianapolis Fire Department officials said Saturday’s explosions sparked two car fires and rattled workers at nearby businesses.

“The building shook before the explosion, and it shook hard, like an earthquake," witness Victoria Hastings said. “I thought someone blew up the jail. It sounded like a boom."

IPL spokeswoman Crystal Livers-Powers said crews worked to repair the manhole covers and to find out what caused the explosions.

"We did find that there were some primary cables that needed to be repaired. We also had to replace some other cables," Livers-Powers said.

The Indiana Utility Regulatory Commission has asked IPL to do a thorough investigation, RTV6's Eboné Monet reported.

"Since July, we've done a complete sweep of our underground networks and manholes, so that's 1,300 manholes, and we've been in each one of those," Livers-Powers said.

Although there were three prior explosions this year, Livers-Powers said they are not common.

"These events are relatively rare when you have a downtown network underground design such as we do, though you will occasionally see manhole incidents,” she said.

IPL officials also said they are researching manhole cover technology to see if there’s a safer option for the Circle City.

Two manholes flew off in Indianapolis on Saturday, igniting two vehicle fires.

Workers at Kim Turner Bail Bonds said they hope the changes come soon.

"(The explosions) blew up two cars to pieces, so yes, we're a little frightened," one worker said.

IPL said they are considering using manhole covers with a lock system that would prevent them from shooting up in the air in the event of another explosion.