Tokyo Gas Co. plans to spend about 10 billion yen to replace old bath and water heaters over a three-year period starting next spring to ensure the safety of household gas appliances, company officials said Thursday.

The plan is aimed at reassuring consumers after a series of fatal carbon monoxide poisonings linked to Paloma Industries Ltd.'s gas-fired water heaters.

Some 300,000 outmoded indoor bath and water heaters that lack features to prevent partial combustion are covered under the plan, Tokyo Gas said.

The company will send letters to owners in the fall urging them to replace their old heaters. The company is expected to take the old products as trade-ins for new ones.

Osaka Gas Co., meanwhile, said it is considering selling bath and water heaters with enhanced safety features at a discount to owners of older models. It plans to spend up to 10 billion yen on safety measures starting from fiscal 2007 starting next spring.