A Rhode Island fitness center is closed until further notice following a chemical explosion.

On July 28, the North Providence Pool and Fitness Center suffered a chemical explosion caused by an underground buildup of chlorine gas.

According to North Providence Mayor Charles Lombardi, residents initially believed the explosion was an earthquake, and one person called him to tell him that “the whole building rumbled” and “the lights flickered.”

The building and nearby library were quickly evacuated while officials investigated the cause. It was determined that the explosion was caused by a buildup of chlorine gas. No injuries were reported, but the facility suffered significant damage.

“The hot tub came right out of the floor,” Lombardi said.

He said that the explosion also resulted in cracks in the walls of the building.

“We’ve drained the pool to try and see if there are any additional cracks in the tiles,” he said.

Joann Lyon, 68, was doing laps in the pool when the building began shaking.

“I was the only one in the pool,” she said. “All of a sudden, I heard a great big noise. It sounded like a bunch of barrels colliding … like, ‘boom boom bang bang!'” She decided to keep swimming, but a lifeguard approached her and told her she needed to evacuate.

“He said, ‘Joann, you need to get out of the pool — the Jacuzzi just exploded,'” she said. “I was grateful that he came right over and told me to get out.”

Lombardi said the pool will remain closed until investigators and insurance representatives can assess the damage. He hopes it will be reopened “as soon as possible.”