Washington, D.C. ? A recall of Magnetix building sets has been expanded after more children swallowed the tiny magnets in them and were seriously injured, the Consumer Product Safety Commission announced Thursday.

In March 2006, Mega Brands Inc. recalled 3.8 million of the magnetic building sets when one child died and four others were seriously injured after they swallowed the magnets. Thursday’s recall includes an additional 4 million sets.

The expanded recall includes all sets except Magnetix sets sold since March 31, 2006, that are age-labeled “6+” and have the following caution label: “CAUTION: Do not ingest or inhale magnets. Attraction of magnets in the body may cause serious injury and require immediate medical care.”

If more than one magnet is swallowed, they can attach to each other and cause intestinal perforation, infection or blockage, which can be fatal. While the hazard was thought to be a problem for children younger than 6, at least 10 injuries involved children between the ages of 6 and 11.

Consumers should contact Mega Brands for a replacement toy. For more information, call Mega Brands at (800) 779-7122.