“Buckwild” star Shain Gandee died from carbon monoxide poisoning inside his Ford Bronco, which was mostly submerged in mud in West Virginia, according to autopsy reports that were released Tuesday.

The deaths of Gandee, his uncle and a friend in the vehicle were ruled accidental, Cpl. B.D. Humphreys of the Kanawha County Sheriff's Office told The Guardian on Tuesday.

"Kanawha County can now report partial findings from the autopsies of Shain Lelyn Gandee, David Dwight Gandee, and Donald Robert Myers. The manner of death is accidental and the cause was carbon monoxide poisoning for all three subjects," Humphreys said to The Guardian.

"There was no damage to the vehicle from an impact. It was just stuck in a mud hole," Humphreys said to ABCNews.com.

The tailpipe was covered in mud, forcing the deadly fumes to go inside the vehicle. The truck was found about a mile from Gandee’s home in Sissonville, the news site said. Police needed a bulldozer to get the vehicle out of the mud.

The family is struggling with the loss of young Gandee, both emotionally and financially. 

His cousin Ashley Green told TMZ the family would be holding a "mud run" in Gandee's honor to raise money for his funeral. It's set to take place on Wednesday night in Proctorville, Ohio. It will cost $10 to participate and all the funds will be donated to his family so they can lay him to rest.

"I know the strain they are going through," Green said to TMZ. "It's hard to provide a proper burial. It's already tough with the loss of family members. ... Expenses are tough as well."

"We're taking all the proceeds and bringing them to us to send Shain's parents," Gandee’s cousin told ABCNews.com. "Whatever expenses they need to keep from being burdened."

A spokesperson for MTV said, "We are shocked and saddened by the terrible news about Shain Gandee, and those involved in this tragic incident. We are waiting for more information, but at this time our main concern is for the Gandee family and their friends. Our thoughts and prayers are with them. Shain had a magnetic personality, with a passion for life that touched everyone he met and we will miss him dearly."

On the show's website, Gandee was described as "the sociable and loyal High School Prom King who loves four-wheeling, but loves his parents most of all."

Gandee's family, father Dale, mom Loretta and older sister Shalena, are struggling after losing Gandee and the uncle.

"Shain's dad lost his son and his brother, two people very important to him in his life, in the same day," Green told ABCNews.com. "They're taking it hard, as they should be."