Chicago ? Dozens of friends were crowded onto a third-floor porch at a party early Sunday when the floor dropped out from under them, sending wood and bodies crashing to the ground. A Kansas City, Mo., man was among the 12 who people died, most of them crushed on the porches below.

At least 57 others were injured, some critically, authorities said.

“There were people covering me. It was pitch black and people were yelling, ‘I’m dying.’ I was assuming I was going to die,” said Natalie Brougham, 22, who walked away with injuries to her hip and shoulder. “I guess I got lucky and only had two or three people on top of me.”

As many as 50 people, most of them in their early 20s, had crammed onto the apartment porch for a party in the city’s affluent Lincoln Park neighborhood when the floor fell about 12:30 a.m., police said. There may have been beer kegs and dancing on the porch as well, authorities said.

Seven men and five women, most of them apparently on the porches directly below, were sandwiched between the falling floors and killed, said Larry Langford, spokesman for the city’s Office of Emergency Management.

“There was chaos,” Chicago Fire Commissioner James Joyce said. “There were people screaming and crying in the alley.”

Partygoers who had been safe inside the apartment said they tried to rescue their friends from the pile of lumber and bodies, while people poured out of a nearby tavern to help.

Eleven people were pronounced dead at the scene, and the Cook County Medical Examiner’s office confirmed that a 12th person was dead on arrival at the hospital.

A structural engineer conducted a preliminary examination and determined that the porch was sound, Reyes said. She said the city was unable to find a construction permit for the porch, which was built in 1998.

Paramedics and friends try to help victims waiting to be taken to the hospital by ambulance in Chicago. The overloaded third-floor porch of an apartment building collapsed during a party early Sunday, sending people and debris crashing to the ground. At least 12 people were killed and as many as 57 others were injured, authorities said.

Authorities released the names of all the victims: Henry Wischerath, 24, of Buffalo, N.Y.; John Jackson, 22, of Kansas City, Mo.; Katherine Sheriff, 23, of Chicago; Eileen Lupton, 22, of Lake Forest; Shea Fitzgerald, 19, of Winnetka; Muhammed Hameeduddin, 25, of Chicago; Margaret Haynie, 25, of Evansville, Ind.; Sam Farmer, 21, of Winnetka; Eric Kumpf, 30, of Hoboken, N.J.; Robert Koranda, 23, of Naperville; and Kelly McKinnell, 26, of Barrington; and Julie Sorkin, 25, of Glenview.