Emergency dispatchers describe the horror and trauma as calls came in of a parade massacre in Highland Park.

GLANVIEW, Illinois. (CBS) – Every day, 911 dispatchers deal with injuries – and they’re used to hearing about emergencies that define the worst days of people’s lives.

July 4 – two weeks ago on Monday – 911 dispatchers answered the first calls – and it was they who heard in real time the tragedy of what happened on the parade route in highland park. They told CBS 2’s Marissa Perlman that it was very different and more traumatic than what they are used to dealing with by now.

Controllers from all over the North Shore answered those first calls on July 4, from Highland Park to Glenview. Dispatchers told us that there was no way to mentally prepare for these calls, and shared what they heard on the other end of the line.

From the Highland Park control tower, Tammy, who has worked as an emergency caller for almost 30 years, received her first calls from the parade just after 10:14 am on Monday, July 4th.

“I don’t want to go through this again,” she said.

Tammy described the first call she answered.

“This guy called and said his girlfriend had been shot,” she said.

Her team of three 911 dispatchers working in the same room immediately called in additional resources. Police officers and fire brigades were sent to the scene, and the dispatchers themselves gave medical advice by phone.

They told the parade participants to find a safe place to hide in place.

“I took two deep breaths and just did what I had to do,” Tammy said.

She said the next few hours were like a blur. With the flow of incoming calls, redundant calls were sent to Glenview Village A GPSDC control center where telecoms work together as a unit.

It was there that Jack Stack picked up the phone.

“It was probably one of the worst calls I’ve ever had to make,” Stopka said. “A lot of screaming – I was told that people were shot, possibly killed. It was a rude call.”

Stack quickly figured out what was going on. According to him, the most difficult moment was to break the news to his team.

“I turned to them and said, ‘There’s an active shooter on the parade in Highland Park,'” Stack said.

For the next 16 hours, Stopka said, he worked on pure adrenaline. He didn’t know exactly how many people were hurt, but he focused on supporting rescuers and paying close attention to every call.

“Sometimes you feel helpless, especially in situations like this,” he said. “But we had people on the way, and there were a lot of them.”

Both dispatchers said they tried to be the voice of calm on the line with neighbors during some of the worst moments of their lives. But they say nothing could have prepared them for this.

“I’ve been doing this for quite some time now and I’ve never had an incident like this – I hope I never have to again,” Tammy said.

“How do you recover from this?” added Stack. “You really don’t.”

That day, dispatchers say they were thankful that paramedics had already arrived on the scene, as well as additional police resources to help people immediately. But controllers are worried about what might have happened if that extra presence hadn’t been on the scene.