The mother of a firefighter killed in massive chemical explosions in Tianjin in 2015 gave birth to twins at a hospital in Wuhan, Hubei province, on Thursday.

Fang Zhiying, 48, and the babies are out of danger, her husband, Pang Fangguo, said on Sunday. He said the doctors had not specified when the mother and newborns－a boy and a girl－could be discharged.

The couple decided to have another baby after their first son, Pang Ti, died at age 24 in the series of blasts at a warehouse in Tianjin.

Pang, who is also 48, said the doctors had warned the couple of the dangers posed to his wife in childbirth at her age, but she insisted.

"The doctors warned me of the risk," Pang said, adding that his wife also had a condition that could cause a stroke. He quit his job as a construction worker in his hometown, Suizhou, Hubei province, to take care of his wife and babies.

"We just wanted another child as a comfort, or a way of remembering my son," he said.

Learning that another couple who lost their only son in the blast had conceived through in vitro fertilization, Fang and Pang also resorted to that method.

"We tried IVF four times before my wife got pregnant in May, which together with the cesarean section cost us hundreds of thousands of yuan, all paid for using the compensation we received for our son's death," he said.

Huge explosions at a warehouse in Tianjin on August 12, 2015, devastated the port area. Pang Ti, the son, worked in the Tianjin fire department and offered to join the fight. He didn't return.

"He had just had surgery and he didn't need to go there," his father said.

After the explosions, the couple hurried from their hometown to Tianjin. It was more than 80 hours after Pang Ti lost contact with his colleagues that his death was confirmed.

His mother insisted on having another child, despite her age and the gossip and the discouraging attitudes of acquaintances, according to the father. At the end of 2015, he agreed to go forward with the attempt.

"I had no idea about the future. The twins will create a lot of pressure for us," he said. "But for now I have to be at the side of my wife and my children."