By Ken Molestina

FORT WORTH (CBSDFW.COM) – Wednesday marked six months since the deadly pileup on Interstate-35W in Fort Worth. Emergency crews who responded to the tragedy spoke about their experience working to help save as many lives as they could.

It was around 6 a.m. Feb. 11 when the massive pileup happened on the southbound lanes of I-35W near the Northside exit. Freezing conditions were to blame for the hazardous roadway.

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Valerie Carson, a MedStar dispatcher, recalled answering the first 911 calls.

“People who were driving the other way were calling and telling us cars were piling into each other and semis were hitting cars, and cars were flying through the air, and people were saying I’m trapped in my car,” Carson said.

She said it was by far the worst highway wreck she’s worked in her more than 40 years of service as an emergency responder.

Body-camera video from a Fort Worth police officer showed a ground-level view of the devastation, and the frantic efforts to rescue those who were trapped.

Six people died and more than 36 were sent to area hospitals.

“And that’s the biggest challenge making sure you don’t leave anybody unaccounted for in that kind of situation,” Carson said.

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The pileup stretched more than three football fields in length, according to investigators who cited the icy conditions that morning.

In dispatch calls, rescuers called for all the help they could get.

Emergency responders said it took them nearly five hours before they could confirm that all the victims on the scene were tended to.

“Very proud of being part of that team with the firefighters, police officers and MedStar personnel,” said Jason Weimer, assistant operations manager for MedStar.

Weimer headed the combined agency effort to search for and rescue victims, which included a MedStar ambulance crew.

Now, six months after the horror, the experience isn’t any less vivid for those who rushed to help.

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“Sometimes you do wonder, was the person I spoke to… what was their outcome, how did they end up?” Carson said.