(CNN) -- The death toll has risen to 21 from a gas leak at a steel company in northern China, state-run media reported Friday.
Company leaders admitted trying to underreport the death toll from the accident, which occurred Monday in northern Hebei province, the state-run Xinhua News Agency said.
Leaders of Hebei Puyang Iron and Steel said Monday that only seven people had died, Xinhua reported, citing a government statement.
The workers were poisoned while trying to put together a furnace, the news agency said.
This deaths happened about two weeks after a gas leak at another steel company in the same province killed at least 17 people.
That incident happened at the Ganglu Iron and Steel Company on December 23.