Nine women were poisoned and died in a Beijing apartment from carbon monoxide released by a gas storage water heater, local media reported Friday.
One woman is in critical condition in hospital, according to Xinhua news agency.
The 20 to 25 year old women were employees of a real estate company and had just moved into the rented apartment on Monday, dpa reported.
The apartment did not have the required smoke discharging pipe for heating up water.
Carbon monoxide is a colourless, odorless and tasteless gas.