Baltimore County emergency services received a number of 911 calls after a CSX freight train struck a truck May 28 at a Rosedale railroad crossing. A representative from CSX also called to report the collision and fire.

An employee at a scaffolding company next to the railroad tracks in Rosedale was one of the first people to see the train leave its tracks after it rammed into a truck last month.

"There's just a train wreck in front of us and it's on fire," the man said, in one of more than 40 recorded 911 calls released Friday by Baltimore County police. "There's just like a fire and it's nasty."

"Did the train derail?" the dispatcher asked. "What type of train is it?"

The questions would continue in 911 calls from Bel Air to Baltimore City, dozens of them, for nearly an hour. The recordings show that the moments after the crash were filled with panic and confusion.

Soon after the derailment, flames ignited the train's chemical cargo and triggered an explosion heard around the Baltimore area. Some people wondered whether a bomb had gone off. Others asked if something had fallen from the sky.

The National Transportation Safety Board continues to investigate the accident, which seriously injured the driver of the truck, hurt four others and damaged several buildings near the crash. Officials have said the truck failed to stop at a poorly marked grade crossing before the wreck.

Multiple chemicals leaked from the train and a car carrying sodium chlorate — a federally designated hazardous material — fueled the explosion. Emergency officials determined that the fumes were not hazardous to public health.

Elise Armacost, Baltimore County public safety spokeswoman, said emergency dispatchers fielded 270 calls between 1:59 p.m. to 2:53 p.m., a large number for a single event, though not a record. By comparison, more than 1,000 calls that came in during the powerful derecho storm that caused widespread damage last June 29.

Callers after the derailment reported broken windows, shaking foundations and billowing smoke — many believing that whatever they heard had occurred next door.

One man told a Baltimore County dispatcher that he had heard a blast "right behind my house."

"It sounds like it went through my house," he said.

The sounds, smells and aftershocks from the accident worried many at the time.

"It's on Lake Drive in Rosedale," a man reported. "I don't know if this thing is going to blow up. … Maybe it's going to blow up. I'm going to get out of here."

"Sir," the dispatcher replied, "I'm trying to get the location."

"I don't want to get myself blown up," he said.

Another man calling from Lake Drive urged dispatchers to send paramedics.

"There's been a terrible train accident," he said. "Hurry up. There's going to be some bad injuries. … Listen, I want to go help them. There's going to be injuries, trust me. The truck got demolished."

Others said their bosses were ordering them to flee.

"I got to go," one man told a dispatcher. "I got to go."

Among the initial calls was a CSX representative reporting the accident.