A north China county government is offering large rewards for information on illegal explosives after a blast caused by an illegal dynamite cache claimed 49 lives on Friday.

Relatives of victims break down at the site of a blast caused by illegal explosives in Ningwu, Shanxi Province, which killed 47 on Friday. [Xinhua]

The rewards of up to 50,000 yuan (6,250 U.S. dollars) to those who report illegally stored explosives in Ningwu County are part of a crackdown across coal-rich Shanxi Province where explosives are used throughout the mining industry.

The authorities had waged a publicity campaign to stop illegal explosives storage and had seized 574 tons of explosives since April, but loopholes in the regulations remained, said Lian Xingyou, deputy director of Shanxi provincial public security department on Monday.

Officials across the province should intensify efforts to crackdown on the production and trafficking of inferior explosives and to raise public awareness on the danger of illegally storing explosives, said Lian.

With vast coal reserves, Shanxi Province is the biggest coal producer in China and its explosives consumption reached 280,000 tons last year, accounting for one ninth of the country's total.

However, many fatal accidents occur in the province each year from illegally stored explosives.

The most recent case happened around 6:30 a.m. on Friday at a house in Dongzhai Village of Ningwu County after a fire ignited at least 200 kilograms of illegal-stored dynamite, killing 49 and injuring 30 others.

Witnesses said villagers who rushed to help extinguish the fire and onlookers died when the bungalow exploded.

DNA tests revealed that Wang Wenyi (also known as Wang Erwen), a 35-year-old man, who allegedly stored the dynamite, and his wife both died in the explosion, said Lian.

Wang, who bought the house from villager Sun Linfeng, his brother-in-law, had been convicted of running an illegal coal mine.

The explosives were hidden in one room and other rooms were occupied by tenants, according to the office of public security in Ningwu County.

The government of Ningwu County, where the blasts happened, has set up a task force to compensate the families of the victims, said Xu Pengfei, an official of the county's publicity office.

The crackdown in Shanxi follows a campaign by the central government against the trade, use and storage of explosives after a series of fatal explosions around the country.

New rules issued by the State Council will come into effect on September 1, requiring a government licence to produce, deal in or transport explosives. They also require designated storehouses where smoking and other unrelated activities are banned.

Last year in China, explosives that were illegally produced, stored and sold caused 101 deaths and 181 injuries in 22 separate accidents.