Engineers worked gingerly to find out more about a slowly growing sinkhole that swallowed a Florida man in his bedroom, believing the entire house could eventually succumb to the unstable ground. 
 
 In this undated photo released by Jeremy Bush, shows his brother Jeff Bush. Jeremy Bush heard a loud crash and screaming coming from his brother's room early Thursday, March 1, 2013 in Seffner, Fla. A... (Associated Press) 
 
 Family members console each other near the home where Jeff Bush disappeared as a large sinkhole opened under the bedroom of his house on Friday, March 1, 2013, in Seffner, Fla. Jeremy Bush told rescue... (Associated Press) 
 
 Jeremy Bush, brother of Jeff Bush, breaks down as he speaks to the media about attempting to rescue Jeff as he disappeared in a sinkhole Friday, March 1, 2013, in Seffner, Fla. Jeff Bush screamed for... (Associated Press) 
 
 An engineer surveys in front of a home where sinkhole opened up on Friday, March 1, 2013, in Seffner, Fla. A man screamed for help and disappeared as a large sinkhole opened under the bedroom of the... (Associated Press) 
 
 Family members console each other near the home where Jeff Bush disappeared as a large sinkhole opened under the bedroom of his house on Friday, March 1, 2013, in Seffner, Fla. Jeremy Bush told rescue... (Associated Press) 
 
 In this undated photo released by Jeremy Bush, shows his brother Jeff Bush. Jeremy Bush heard a loud crash and screaming coming from his brother's room early Thursday, March 1, 2013 in Seffner, Fla. A... (Associated Press) 
 
 Jeff Bush, 37, was in his bedroom Thursday night when the earth opened and took him and everything else in his room. Five other people were in the house but managed to escape unharmed. Bush's brother jumped into the hole to try to help, but he had to be rescued himself by a sheriff's deputy. 
 
 Engineers were expected at the home to do more tests after sunrise Saturday. They spent the previous day on the property, taking soil samples and running various tests _ while acknowledging that the entire lot was dangerous. No one was allowed in the home. 
 
 "I cannot tell you why it has not collapsed yet," Bill Bracken, the owner of an engineering company called to assess the sinkhole, said of the home. He described the earth below as a "very large, very fluid mass." 
 
 "This is not your typical sinkhole," said Hillsborough County administrator Mike Merrill. "This is a chasm. For that reason, we're being very deliberate." 
 
 Officials delicately addressed another sad reality: Bush was likely dead and the family wanted his body. Merrill, though, said they didn't want to jeopardize any more lives. 
 
 "They would like us to go in quickly and locate Mr. Bush," Merrill said. 
 
 Two adjacent houses were evacuated and officials were considering further evacuations. Even the media was moved from a lawn across the street to a safer area a few hundred feet away. 
 
 "This is a very complex situation," said Hillsborough County Fire Chief Ron Rogers. "It's continuing to evolve and the ground is continuing to collapse." 
 
 Sinkholes are so common in Florida that state law requires home insurers to provide coverage against the danger. While some cars, homes and other buildings have been devoured, it's extremely rare for them to swallow a person. 
 
 Florida is highly prone to sinkholes because there are caverns below ground of limestone, a porous rock that easily dissolves in water. 
 
 "You can almost envision a piece of Swiss cheese," said Taylor Yarkosky, a sinkhole expert from Brooksville, Fla., said while gesturing to the ground and the sky blue home where the earth opened in Seffner. "Any house in Florida could be in that same situation." 
 
 A sinkhole near Orlando grew to 400 feet across in 1981 and devoured five sports cars, most of two businesses, a three-bedroom house and the deep end of an Olympic-size swimming pool. 
 
 More than 500 sinkholes have been reported in Hillsborough County alone since the government started keeping track in 1954, according to the state's environmental agency. 
 
 The sinkhole, estimated at 20 feet across and 20 feet deep, caused the home's concrete floor to cave in around 11 p.m. Thursday as everyone in the Tampa-area house was turning in for the night. It gave way with a loud crash that sounded like a car hitting the house and brought Bush's brother running. 
 
 Jeremy Bush said he jumped into the hole but couldn't see his brother and had to be rescued himself by a sheriff's deputy who reached out and pulled him to safety as the ground crumbled around him. 
 
 "The floor was still giving in and the dirt was still going down, but I didn't care. I wanted to save my brother," Jeremy Bush said through tears Friday in a neighbor's yard. "But I just couldn't do nothing." 
 
 He added: "I could swear I heard him hollering my name to help him." 
 
 A dresser and the TV set had vanished down the hole, along with most of Bush's bed. 
 
 A sheriff's deputy who was the first to respond to a frantic 911 call said when he arrived, he saw Jeremy Bush. 
 
 Deputy Douglas Duvall said he reached down as if he was "sticking his hand into the floor" to help Jeremy Bush. Duvall said he didn't see anyone else in the hole. 
 
 As he pulled Bush out, "everything was sinking," Duvall said. 
 
 Engineers said they may have to demolish the small house, even though from the outside there appeared to be nothing wrong with the four-bedroom, concrete-wall structure, built in 1974. 
 
 Jeremy Bush said someone came out to the home a couple of months ago to check for sinkholes and other things, apparently for insurance purposes. 
 
 "He said there was nothing wrong with the house. Nothing. And a couple of months later, my brother dies. In a sinkhole," Bush said. 
 
 ___ 
 
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 Online: http://www.dep.state.fl.us/geology/feedback/faq.htm(hash)17 ||||| SEFFNER 
 
 Jeremy Bush just went to bed when he heard what sounded like a car hitting the house. Then screams from his brother Jeffrey's bedroom. 
 
 "Help me! Help me!" 
 
 Someone flipped the lights. Jeremy, 36, threw the door open, revealing a sight that defied belief: The earth had opened beneath his brother's bedroom and was swallowing everything in it. The tip of Jeffrey's mattress was the only thing left, and it was sinking into a churning sinkhole. 
 
 Someone in the house called 911: "The bedroom floor collapsed and my brother-in-law is underneath the house." 
 
 Hillsborough County sheriff's Deputy Douglas Duvall was not sure exactly what that meant until he got to the one-story house at 240 Faithway Drive just after 11 p.m. Thursday and found Jeremy Bush trying in vain to dig into a hole threatening to claim him. Duvall pulled him to safety. 
 
 Then the waiting began. 
 
 An army of rescue authorities came, followed by an army of media, and everyone tiptoed around yellow caution tape and bulging television station cables Friday as the rescuers tried to figure out what they could do, safely, to find a man buried in an expanding sinkhole. 
 
 In the midst of the scrum sat the friends and family of 37-year-old road worker Jeffrey S. Bush, sobbing, consoling each other, screaming at rescue workers, struggling to come to terms with the fact the rubble under the aqua home Bush lived in may be his final resting place. 
 
 No officials declared Bush dead, but rescue efforts were hampered by the volatile nature of sinkholes. Authorities did not give the family false hope. Still, some had it. 
 
 "Until I see him, until they get him out," Amber Wicker, Jeffrey's friend, said midday, "you have to hold on." 
 
 • • • 
 
 The noise that startled the residents of the Seffner home, experts say, was a cover collapse sinkhole — the rarest kind and, because of its suddenness, often the most catastrophic. 
 
 Cover collapse sinkholes usually occur in areas where a layer of clay sits atop the Swiss cheese of limestone that lies beneath the ground in this part of the state, said University of South Florida geology professor Mark Stewart. 
 
 The limestone is pocked with caverns. Something triggers the clay atop a cavern to begin trickling into the hole, more and more of it drops away until all that's left is a slender land bridge. Then the bridge falls. 
 
 The bang is the last bit of sediment falling into the bottom of the cavern, Stewart said. 
 
 The sinkhole that took Jeffrey Bush was 30 feet wide and 20 feet deep, Hillsborough County Fire Rescue Chief Ron Rogers estimated. It was confined to the home, not visible from the outside. 
 
 Sinkholes can occur naturally. They can also be caused by humans building homes, stores or retention ponds atop fragile land, or pumping too much water out of the aquifer. 
 
 In a record cold snap in 2010, Plant City strawberry farmers pumped about 1 billion gallons of water from the aquifer to protect their crops. The aquifer dropped some 60 feet, causing multiple sinkholes in the area. 
 
 Stewart was skeptical that over-pumping caused this sinkhole. Sandy Nettles, a private geologist in Palm Harbor, said recent rainfall may have played a role. 
 
 January and February were both drier than normal. That can cause the aquifer to dip, weakening underground support for the land above a cavern, Nettles said. A recent downpour could have washed away what little remained of the cap atop the cavern. 
 
 "Obviously that cavern was ready to go," Nettles said. "It doesn't take much of a fluctuation in the water table to make it slip." 
 
 In the early 1980s, state officials were determined to solve the mysteries behind the cause of sinkholes. In 1981, during a drought, a gigantic sinkhole opened in Winter Park, swallowing a car dealership, a home and part of a road. The Legislature created a research institute at the University of Central Florida. 
 
 After a while, according to Stewart, legislators cut funding. 
 
 "They figured, 'We don't need this any more,' " he said. "We haven't had another one of these in the news in a while." 
 
 • • • 
 
 The Bush brothers both worked for the Florida Department of Transportation, Jeremy said, doing roadside assistance. His brother moved to the home three months ago from Zephyrhills. They lived there with Jeremy's fiancee, Rachel Wicker, their 2-year-old daughter, Hanna, and two other relatives. 
 
 Leland Wicker, owner of the home, was vacationing in North Carolina on Thursday night. He said the four-bedroom home, built in 1974, passed a sinkhole inspection in August and is insured. 
 
 The friends and family of Jeffrey Bush gathered near the house Friday morning and, adhering to the cordoned off safety zone, dragged lawn chairs in front of the homes across the street. Many of them still wore pajamas. They walked in circles, their eyes glazed, rimmed in red, their hands trembling, gripping cigarettes. Some talked about charging past the workers and digging Bush out themselves. Some didn't talk, just clinging to stuffed animals and staring across the street. 
 
 And they watched. 
 
 About noon, they watched a team send an underground camera into the stormwater pipes. About 2:30 p.m., they watched workers roll drilling equipment out front of the home. At 3, they watched the equipment stop working and then watched a man crawl underneath the equipment with a wrench and work for more than 30 minutes. 
 
 Just after 4 p.m., a sheriff's deputy asked them to move back, for their safety. Emotions boiled over. 
 
 Jeremy Bush cursed and looked across the street at the workers in the yard. 
 
 He stormed off down the street, threatening to punch firefighters. An older woman ran after him, and they met in an embrace in the middle of the street, both crying. Then Jeremy walked off, and the woman went back to her lawn chair, sobbing. 
 
 "My baby's in a hole," she said. 
 
 About 6:30 p.m., a line of county officials held a news conference to say they were doing all that they could. 
 
 "Until we know where it's safe to bring our equipment," Chief Rogers said, "we're really handicapped." 
 
 Then Deputy Duvall, the first on scene, spoke. 
 
 Duvall's shift ended at 7 a.m. He tried to sleep, but couldn't. He came back because he wanted to be here. This neighborhood had warmed his heart with how it helped the family, he said. 
 
 "These are everyday, working people. They're good people." 
 
 Then he looked at the cameras. He had a message for viewers. 
 
 "You guys out there, if you know these people, if you know this neighborhood, pray for them." 
 
 Times photographer Luis Santana and staff writers Craig Pittman and Stephanie Bolling contributed to this report.
– Engineers are still gingerly trying to find a 37-year-old Florida man who disappeared into a sinkhole that opened up in his bedroom yesterday. Jeffrey Bush is presumed dead, and authorities say the sinkhole is so dangerous they can't risk simply sending searchers into it, reports AP. It's about 30 feet wide and 20 feet deep, but it's growing slowly and expected to collapse even more. "This is not your typical sinkhole," says one Tampa-area official. "This is a chasm. For that reason, we're being very deliberate." Bush's family is livid, especially his brother, Jeremy, who tried in vain to pull his brother out when the sinkhole suddenly appeared Thursday night. He had to be rescued himself by a firefighter. "I could swear I heard him hollering my name to help him," Jeremy tells the Tampa Bay Times. The newspaper says this is a "cover collapse sinkhole," the rarest and most dangerous kind because there's no warning. "You can almost envision a piece of Swiss cheese," explains one geologist, referring to the region's porous limestone.