OMAHA, Neb. (AP) -- Authorities on Tuesday recovered the body of a second worker who was killed when an Omaha manufacturing plant collapsed, while federal investigators tried to pinpoint a cause of the industrial accident that killed two and injured 17.
Interim Fire Chief Bernard Kanger said authorities retrieved the body from the International Nutrition building at 3:45 p.m. Authorities believe no other people are in the building.
Kanger said the two men killed were found on the second floor, but the bodies were not near each other. Thirty-eight people were in the animal feed and supplement plant on Monday when it collapsed.
Authorities said they recovered the body of 53-year-old Keith Everett, of Omaha, on Monday night. The second worker killed was identified Tuesday evening as 47-year-old David Ball, of Omaha.
Crews from Omaha and Lincoln had suspended their work Monday night because of shifting winds, cold temperatures and the dangerous rubble. They restarted Tuesday morning with a team of specially trained firefighters. The team also took a structural engineer to help make sure their efforts didn't further destabilize the crumpled structure, putting rescuers at risk.
"After hours of hard work under extremely dangerous conditions, members of both teams were able to recover the (second) victim," Kanger said.
Meanwhile, authorities were still trying to determine a cause.
Occupational Safety and Health Administration investigators were on the scene of the accident Tuesday morning as they took the lead in investigating the collapse, OSHA spokesman Scott Allen said.
It was too early to know what might have caused part of the three-level International Nutrition plant to collapse, Allen said. The plant makes nutritional products that are added to livestock and poultry feed.
Some witnesses reported hearing an explosion before a fire that burned some workers and the partial collapse of the plant.
"There are many questions yet to be answered about what caused this disaster, but I am confident that the answers provided by federal, state and local officials can offer lessons that will help avoid tragedies like this one in the future," U.S. Labor Secretary Thomas Perez said in a written statement.
One company official cast doubt on reports that an explosion caused the collapse and fire.
Kim Nguyen, the international marketing manager for the company, said an investigator told company officials there was no explosion, "only a collapse of the building." She said she could not recall the name of the investigator, and said the person did not know what caused the building to collapse.
Nguyen urged people to wait for investigators to complete their study before drawing conclusions.
"This is a nightmare to people here," Nguyen said. "It's just shocking to everyone right now. We work as a family."
Calls and emails to other company officials were not immediately returned Tuesday.
Besides the two deaths, 17 people were injured, including 10 workers who were sent to hospitals. Hospitals reported that four of the 10 had been released by Tuesday.
Monday's deaths were not the first workplace fatality to occur at the plant.
OSHA records show International Nutrition was assessed more than $13,000 in penalties for a 2002 accident that killed a 45-year-old worker. The worker died when he fell into a moving mixer that he was cleaning.
The plant also was cited for six safety violations in 2012, ranging from a lack of facilities to flush dangerous chemicals from workers' eyes and skin to concerns over lacking safeguards for some equipment.
Associated Press reporter Grant Schulte in Lincoln, Neb., contributed to this report.