SEFFNER, Fla. (CBS News)-- A man was missing and feared dead early Friday after a large sinkhole opened under the bedroom of a house near Tampa. His brother says the man screamed for help before he disappeared.
The 36-year-old man's brother told rescue crews he heard a loud crash around 11 p.m. Thursday, then heard his brother screaming for help.
"When he got there, there was no bedroom left," Hillsborough County Fire Rescue spokeswoman Jessica Damico said. "There was no furniture. All he saw was a piece of the mattress sticking up."
The brother called 911 and frantically tried to help his brother. An arriving deputy pulled the brother from the still-collapsing house.
There's been no contact with the man since then and neighbors on both sides of the Seffner home have been evacuated.
By early Friday, Hillsborough County Fire Rescue officials determined the home had become too unstable to continue rescue efforts.
Hillsborough County Fire Chief Ron Rogers told a news briefing that extra-sensitive listening devices and cameras were inserted into the sinkhole. "They did not detect any signs of life," he said.
Damico said that at the surface, she estimates the sinkhole is about 30 feet across but officials say the sinkhole spreads to about 100 feet across below the surface. Authorities were waiting for an engineering crew to bring monitoring equipment to determine the borders of the sinkhole, she said.
"The entire house is on the sinkhole," Damico said.
Sinkholes are common in seaside Florida, whose underlying limestone and dolomite can be worn away by water and chemicals, then collapse.
Engineers condemned the house, reports CBS Tampa affiliate WTSP.
Janell Wheeler told the Tampa Bay Times newspaper she was inside the house with four other adults and a child when the sinkhole opened.
"It sounded like a car hit my house," she said.
The rest of the family went to a hotel but she stayed behind, sleeping in her car.
"I just want my nephew," she said through tears.
2013 CBS Interactive Inc. All Rights Reserved. This material may not be published, broadcast, rewritten, or redistributed. The Associated Press contributed to this report.