The total death toll in the gas pipeline leak in north China's Hebei Province had risen to 21 as company executives confessed to 14 more deaths, said local authorities Friday.

Senior executives of the Hebei Puyang Iron and Steel Co., Ltd. confessed late Thursday night that they had covered up the death toll, according to a statement of Wu'an Municipal Government.

Workers were poisoned while assembling a furnace at 11:45 a.m. Monday in Hebei Puyang Iron and Steel Co., Ltd. when the accident happened.

The company originally reported on Tuesday that 16 workers were poisoned in the accident, among whom seven were confirmed dead and the other nine were under medical treatment.

The pipeline that the gas leaked from belongs to Puyang company, and was constructed by Nanjing Sanye utility installment company.