ZHENGZHOU -- An explosion took place Friday at a gas plant workshop in the city of Yima, Henan province, causing multiple injuries and deaths.

As of 7:13 am Saturday, 10 people have been confirmed dead, and 19 were reported as seriously injured. Five more people remain unaccounted for according to China Central Television.

The accident happened around 6 pm, and the injured were sent to the hospital, according to a government source at Sanmenxia city, which administers Yima.

The explosion did not involve tanks of dangerous materials, local government said.

"The sound was extremely loud, with a ball of fire and clouds of smoke in the air," said a local citizen who was 500 meters away from the gas plant when the explosion occurred, quoted by the Beijing News.

"Customers who bought goods outside were scratched by broken glass," he said.

The factory was this month named the first provincial-level enterprise to put in place a double prevention system for safety production risks in Henan.

The Yima gas plant of Henan Gas Co Ltd was established in 1997, covering an area of 87 hectares, with more than 1,200 employees, according to a Southern Metropolitan Daily report.

It is listed as a key monitoring enterprise of the Ministry of Ecology and Environment, the report said.

Investigation into the cause of the accident is underway.