"It is a terrible accident. The car flipped, it's on its side," one person on the scene says in the recording, which includes calls from three different people.
A Walmart truck driver who, according to police, hadn't slept in more than 24 hours has been charged in the pileup, which involved six vehicles on the New Jersey Turnpike and killed Morgan's friend and fellow comedian James "Jimmy Mack" McNair.
The 30 Rock star, 45, was returning from a Delaware show with McNair and five others when the truck swerved into their Mercedes limo bus.
"It was like a movie in slow motion," one eyewitness previously told PEOPLE. "The Mercedes spun out of control and then flipped over and came to rest on the driver's side. … The windshield was broken. You could see blood everywhere."
Morgan remains in critical but stable condition at Robert Wood Johnson University Hospital in New Brunswick, New Jersey, after undergoing surgery on his leg. Two other passengers were also injured and remain hospitalized.
Morgan's fiancée, Megan Wollover, took to social media Monday to thank fans and offer condolences for McNair.
"Thank you so much for the outpour of support following the accident. Your well wishes mean more than you can imagine, and I know that Tracy can feel the love and positive energy," she posted on Facebook. "And to Jimmy Mack, you will truly be missed. You have always been someone very special to Tracy and all of us, and the world will not be the same without you."
Wollover, the mother of Morgan's 11-month-old daughter Maven Sonae, also Tweeted, "My [heart] goes out to all the family and friends that were also in the car accident along with my fiancé #TracyMorgan. Pls pray 4 full recoveries."
FX Networks, which planned to begin production on a series starring Morgan in August, also offered support for the actor, saying "his show will be waiting for him."
"The only thing we are concerned with is the health and recovery of Tracy Morgan and the victims of this tragic accident," the statement read. "We will support Tracy and his family in every way possible throughout his recovery"