Rescuers digging through the concrete debris of a collapsed Bangladesh sweater factory heard survivors pleading for help Tuesday, a day after the nine-story building toppled when a boiler exploded, killing at least 30 people and trapping 200.

Nine bodies were pulled from the rubble overnight, but rescuers were hopeful that more lives could be saved. They used crowbars and their bare hands to claw through the debris near Savar (search), an industrial town 20 miles northwest of the capital, Dhaka (search).

One survivor walked out of the rubble Tuesday.

"He just crawled out of an open space all by himself, stood dazed for a bit and collapsed in front of us," said Anisul Islam, a rescue volunteer. "We were amazed. It was a real miracle."

The survivor, who was trapped on the ground floor, was later identified only as Polash, 25. He was recovering in a hospital.

Other survivors were heard calling for help and begging for water from under the debris. Rescue workers were using welding machines to clear rubble so survivors could have air.

Nurul Islam, a police official supervising the rescue work, said about 200 people were feared trapped beneath the mangled sweater factory that collapsed Monday.

Anxious relatives joined soldiers, firefighters and volunteers in the search for trapped workers.

"What sin have we committed? Why would Allah take him?" said Sharmin Akhtar, 23, as she searched for her husband, Jahangir Alam.

One survivor, Helaluddin, said he was on the seventh floor along with about 90 workers when the building collapsed.

"I was overseeing the workers when there was a big bang and [the] building suddenly started shaking and going down," said Helaluddin, who uses one name. "I was buried under slabs of concrete before I could realize what had happened."

Abdus Salam, a 15-year-old working the overnight shift when the factory collapsed, had promised to buy candy for his mother and younger sister with his first-ever paycheck, his family said.

"I will never see the face of my son — he was my soul," Fatema Begum wailed as relatives lost hope for Salam's survival. "Who will bring sweets for me now?"

Salam dropped out of school to work at the factory as a knitting machine operator earning $30 a month.

The government has ordered an investigation into the accident.

The factory, Spectrum Sweaters Ltd., (search) produced nearly 80,000 pieces of clothing a day for export, mainly to the United States, Belgium and Germany. Bangladesh has about 2,500 garment factories employing about 1.8 million workers.