Importation of liquefied natural gas from Algeria, which began several weeks ago, will require modifications of some water heaters in homes of Washington area residents.

According to the Washington Gas Light Co., which sells natural gas throughout the area, burners must be replaced on certain models of heaters for efficient operations supplies starting late in May.

WGL has assigned all of its meter readers to inspect water heaters on their regular rounds and where it is necessary to replace burners, it will be done without a charge to the customer.

Other gas appliances are not expected to be adversely affected by use of the Algerian gas, which burns hotter and produces a longer flame than domestic supplies, WGL stated.

The Washington utility conducted a series of tests before concluding that "a few models" of water heaters would not function properly, however. WGL said there is insufficient clearance above the burner to accommodate the longer flame on the models in question.

Baltimore Gas & Electric Co., which also will share some of the imported gas supplies, has launched a similar program of pinpointing heaters where adjustments are necessary, notifying customers and making appointments for burners replacements.

The liquefied natural gas is being shipped to the United States through Cove Point, Md., on the Chesapeake Bay. The purchaser is Columbia Gas Transmission Corp., which sells the gas tosuch local distributing firms as WGL and BG&E.