In a Kunshan city square on Saturday night, residents light candles to remember those who died or were injured in the factory explosion that morning. Shen Peng / Xinhua

Communities, doctors rush to help as blast kills more than 70 workers, report Wei Tian and Cang Wei in Kunshan, Jiangsu, and Su Zhou in Beijing.

Chinese Valentine's Day on Saturday was a traditional day for loving couples to have happy reunions.

But for some in Kunshan, Jiangsu province, it was a day of tragic separation.

At about 7:30 am, Wen Zhao was awakened by a huge blast from a nearby factory.

Unlike many who ran for their lives, the migrant worker from Henan province rushed to the scene. That's because his 25-year-old wife, Liu Jinhua, works there.

"There were bodies lying on the ground in disorder, and the injured were struggling to stand up," Wen said with tears in his eyes, recalling the painful sight.

"There was so much dust that I couldn't recognize anyone's face. But I eventually heard a weak groan from my wife, and I pulled her out and carried her to the ambulance."

A total of 264 workers were in the wheel-polishing workshop of the auto parts plant when the explosion occurred at 7:37 am. Official figures showed that 44 died at the scene, and 27 others died on the way to hospitals. About 187 of the injured were receiving medical treatment.

The blast, which investigators said was likely an aluminum dust explosion, shattered the two-story building of Kunshan Zhongrong Metal Products, a Taiwan-funded auto parts producer and sub-supplier for General Motors.

The severity of injuries inflicted by the blast stunned even some seasoned doctors.

"During my 27-year career, I have never seen a situation where every patient suffered burns to more than 80 percent of their body," said Zhang Qin, a doctor at the burn department of Shanghai's Ruijin Hospital. He was among the first experts to arrive. His team treated about 40 burn patients on Saturday morning.

Zhang said the death rate from severe blast injuries is "quite high" and that the final casualty number is likely to climb.

President Xi Jinping ordered an all-out effort to treat the injured and comfort the families of the dead. He has demanded a full investigation into the accident and harsh punishments for those responsible.

Premier Li Keqiang called for safety checks to prevent similar tragedies in the future.

Families and friends quickly gathered at the hospitals that received the wounded. Many of them traveled long distances from other cities.

But their loved ones were often not easy to find. Because of the large number of casualties and frequent transfers of patients, the hospitals had few options for keeping track of them. In many cases, they quickly collected saliva samples for DNA matching and wrote down contact information for future use.

A 32-year-old man from Anhui province who gave his surname as Cheng said he had tried three hospitals but still couldn't find his wife, who had been working in the factory.

Cheng, who was also a former employee of Zhongrong, said working conditions at the factory were "the worst" in Kunshan's industrial development zone.

"In the dusty environment, the only protection workers got was a mask and gloves. The air-filtering equipment is basically useless," he said.

Workers at Zhongrong could earn 5,000 yuan ($830) per month, high pay compared with neighboring factories.

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