PHOENIX (3TV/CBS 5) — Five people, including several Phoenix firefighters, have been taken to a hospital after a crash involving a fire engine and a flatbed delivery truck late Monday morning.

“I was working at my desk and heard a giant boom,” said Celeste Elias, who works at a business near where the crash occurred on Wier Avenue, near 40th Street and Roeser Road in southeast Phoenix. Fire officials say that firefighters were eastbound on Wier while responding to a medical emergency when the collision happened.

Elias said it sounded like an explosion. “I looked up from my desk and saw a big plume of brown dust,” she said, adding that the dust prevented her from seeing across the street.

As the dust began to settle, she saw several firefighters get out of their truck. “It was pretty substantial and pretty quickly, lots of people flooding out,” Elias said. She also saw firefighters checking on the driver of the other truck and said no one looked seriously hurt.

In all, four firefighters and the driver of the flatbed truck were taken to a hospital as a precaution in stable condition. Video from the scene showed damage to the fire truck’s windshield and front passenger side tire. Officials say the gas tank on the flatbed truck was also punctured but was quickly sealed by hazardous materials crews.

Phoenix police officers are investigating what led up to the crash.