At least 46 children have died over the last eight years after being struck by closing automatic garage doors, government safety experts said this week.

They urged homeowners to install only doors that have an automatic reverse feature, and to replace any that do not.

The children were killed when garage doors did not reverse automatically, the Consumer Product Safety Commission said.

The agency urged homeowners to help save children's lives by checking garage door openers and to have them repaired or replaced immediately if they fail to reverse after striking an object.

Many garage-door units manufactured before 1982 do not have automatic reverse.

"Some older door openers are equipped with a device that only stops the closing door and does not reverse it when it strikes an object," the commission said.

Some of the older doors may have a device intended to cause the closing door to reverse but, because of wear, poor maintenance or a bad installation, may not be safe enough to prevent child deaths, the commission said.

It said these door-closing devices cannot be adjusted or repaired to provide the safety available in garage door openers produced in 1982 and after.

Homeowners concerned about their doors can check on safety by placing a two-inch wooden block in the path of the door, the commission said.

"If the door does not promptly reverse on striking the block, the unit should be disengaged and a service technician called to see if repairs are needed," the commission added.

It said the old garage door should be replaced if it does not have a working automatic reverse.

The commission advised that additional safeguards now are available to protect children.

The commission said closing units made after 1982 can be improved with an "electric eye" near the floor to reverse a closing garage door automatically whenever an object crosses the path of the door.

It also advised homeowners to relocate wall switches out of the reach of young children and to keep remote control units in the glove compartment of the car.