BEIJING (AFP) - As the child of poor Chinese farmers Yang Weigang never dreamt of being a firefighter. But when he grew up, the chance of making a little more money than his poverty-stricken parents outweighed the dangers.

Yang, 24, was among the first to respond to a fire at a hazardous goods storage warehouse in the port of Tianjin last week. As efforts were made to contain the blaze, two monumental explosions sent flames towering into the sky and left scenes of apocalyptic devastation.

He has not been seen since, one of 48 firefighters still missing. A total of 56 firefighters have been confirmed among the 114 dead, with seven corpses yet to be identified.

"There are no jobs in our hometown, so when Yang Weigang heard from a friend the port was hiring firefighters, it was the best job he could find," his father Yang Jie told AFP.

Nearly all of China's firemen are contract labourers - young, poor men from the countryside who receive limited training, provoking public concern over the professionalism and capabilities of the emergency service.

Questions have been raised over whether poorly trained firefighters responding to the Tianjin blaze could have contributed to the detonations by spraying water over calcium carbide, listed as being at the site, which reacts with it to produce highly combustible acetylene gas.

The Yang family have been farmers in Yu county in Hebei province, which borders both Tianjin and Beijing, for generations. The younger Yang was the first to leave, spending four years as a soldier before being lured to the port fire brigade by monthly pay of more than 3,500 yuan (S$770), nearly double what his father makes as a farmer and occasional handyman.

The sons of 10 other families from the area did the same, his father said, all of them poorly educated but looking to eke out a marginally better life than their parents.

Yang's training was little more than morning runs, a brief introduction on using equipment and being given a book to study on firefighting techniques, his father said.

"We only saw our son once a year after he started working as a firefighter," Yang Jie said wearily. "He had a girlfriend, we hoped they would get married and give us a grandchild.

"He was our only son," he added.

Yang was one of the hundreds of millions of Chinese who have left the countryside to seek work in major cities.

They are often treated as second-class citizens in their adopted cities, denied the same social benefits as locals.

China's firefighters divide into three levels: those employed directly by the ministry of public security - which also oversees the police - those who work for local governments, and contract teams established by businesses with a high risk of fire.

Nearly all the country's 130,000 fire personnel come under the third category, the ministry says, including those who worked for the port of Tianjin.

Salaries are generally around 3,000 yuan a month and turnover is typically high, according to relatives and media reports.

Chinese media have compared firefighters' training and compensation unfavourably with those in developed countries.

Firefighters in the US earn about $49,000, slightly above the national average, according to the Bureau of Labor Statistics. Those in London undergo up to 16 weeks of classroom and practical training and a battery of medical, physical and psychological evaluations.

"The firefighter system should be professionalised, we should learn from the experience of other countries," said one user on Sina Weibo, a Twitter-like service. "We should not be sending 17 or 18-year-old kids to the front lines of disasters." Another poster wrote: "These kids are just a way for the government to save money and keep public funds for themselves. What happens in the next large fire? Will we send professionals to save lives or kids?" But authorities seeking to quash criticism of the system have said that any questioning of the firefighters' abilities denigrates the memories of the dead.

"Don't add salt to the wound," Zhou Tian, the fire chief of Tianjin, told the People's Daily, the Communist Party's mouthpiece.

"If the relatives of firefighters who sacrificed their lives and were injured and resting in hospital heard that you questioned the way they put out the fire, what would they feel?" Liu Zhiqiao was among the first on the scene, before the deadly blasts, according to his family. All but one of his 25-man brigade are missing, and the sole exception has been confirmed dead.

"I still have hope, but I don't know why," said his mother, who only gave her surname, Yang. "I've been to every hospital in the city and I still can't find him, but the government also won't tell me anything."