For eight years, the little flat, green-glowing night lights were given away as promotional items, usually with the printed name of a company. Now a Willmar, Minn., manufacturer, Molenaar LLC, is recalling about 315,000 of the lights out of concern that they could melt, start a fire or deliver an electric shock.

The voluntary recall was announced last week by the Consumer Product Safety Commission. The company has heard of four instances of the electroluminescent night lights melting, "resulting in minor property damage." One light is shaped like a house. The other is square with a rounded top.

The recalled models have "71980 U.S.A." molded on the back, just above the prongs of the plug. If you have one, the CPSC advises, throw it away.

If you want to find out whether the things you buy have been recalled because they could hurt you, check out recalls.gov, which includes recall announcements by a welter of federal agencies.

UPDATE: A Molenaar company VP alerted me today that the recall only affects the products identified on this web page, and not everything stamped with 71980. If you don't know if a certain nightlight is covered by the recall, call this toll free number: (877) 719-4442.