Story highlights Man's brother talks to CNN's "AC360" about trying to save his brother

Site remains unstable, complicating recovery efforts

"It's a tough situation. It's even tougher for the family," says a fire chief

Authorities release the audio of a 911 call: "The house just fell through"

The ground just swallowed him up.

A Florida man fell into a sinkhole that opened suddenly Thursday night beneath the bedroom of his suburban Tampa home, calling out to his brother for help as he fell, the brother said Friday.

"I ran toward my brother's bedroom because I heard my brother scream," Jeremy Bush told CNN's "AC360."

"Everything was gone. My brother's bed, my brother's dresser, my brother's TV. My brother was gone."

Bush frantically tried to rescue his brother, Jeff Bush, by standing in the hole and digging at the rubble with a shovel until police arrived and pulled him out, saying the floor was still collapsing.

"I couldn't get him out. I tried so hard. I tried everything I could," he said through tears. "I could swear I heard him calling out."

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Jeremy Bush and four other people, including a 2-year-old child, escaped from the blue, one-story 1970s-era home in Seffner, a Tampa suburb.

What began with hopes of rescue turned into a body recovery operation after monitoring equipment failed to detect any signs that Jeff Bush survived the fall into the hole, according the Hillsborough County Sheriff's Office.

Rescuers still hadn't gone into the hole -- it's too dangerous, Fire Chief Ron Rogers told reporters. Authorities say they worry the hole is still spreading and the house could collapse at any time.

"Until we know where it's safe to bring the equipment, we really are just handicapped and paralyzed, and can't really do a whole lot more than sit and wait. It's a tough situation. It's even tougher for the family," Rogers said.

The sinkhole is about 20 feet to 30 feet across and may be 30 feet deep, said Bill Bracken, president of an engineering company assisting emergency workers. The hole was originally reported to be 100 feet across, but that is the diameter of the safety zone surrounding it, Bracken said.

"It started in the bedroom, and it has been expanding outward and it's taking the house with it as it opens up," he said.

As the sinkhole continued to deepen, nearby homes were evacuated as a precaution.

On Friday, the Hillsborough County Sheriff's Office released a 911 call from the night before.

"The house just fell through," a female voice says on the recording. She asks for an ambulance and the police.

"The bedroom floor just collapsed, and my brother-in-law is in there. He's underneath the house," she says.

Jessica Damico, Hillsborough County Fire Department spokeswoman, said about 40 police and firefighters were standing by at the scene Friday morning. Meanwhile, engineers hoped to use more sophisticated equipment to get a three-dimensional image of the sinkhole.

Family members were also on hand, waiting out what they feared would be a devastating day.

"I'm praying that there's an air pocket in there ... but I can't see nobody surviving that long in a hole like that. There was too much dirt, too much stuff," Jeremy Bush said. "He was my brother, man, I loved him."

Sinkholes are common in Florida, according to the Florida Department of Environmental Protection. The state lies on bedrock made of limestone or other carbonate rock that can be eaten away by acidic groundwater, forming voids that collapse when the rock can no longer support the weight of what's above it.

Hillsborough County is part of an area known as "sinkhole alley" that accounts for two-thirds of the sinkhole-related insurance claims in the state, according to a Florida state Senate Insurance and Banking Committee report.

But Mike Merrill, county administrator for Hillsborough County, stressed Friday that the sinkhole in question was not "your typical sinkhole."

"They still have not been able to find the boundaries of the underground chasm. For that reason, we're being very deliberate, he said. "We're very frustrated. But we're pursuing it as quickly as we can, as safely as we can."