More than 1 million elementary school-age children may be left unsupervised in households containing at least one gun, two researchers at the Centers for Disease Control have estimated.

The estimate is based on a telephone survey conducted in Texas in 1989 of more than 1,000 households. It included questions about demographics, child supervision and firearm ownership.

About 55 percent of the Texas households surveyed reported owning guns. Among households with children, 54 percent had at least one firearm. Of those, 70 percent reported having more than one gun and 66 percent had a handgun.

Of the homes with firearms and elementary-school children, 15 percent had an unsupervised or "latchkey" child at home after the dismissal of elementary school.

Researchers applied the 15 percent estimate -- the proportion of Texas households with both guns and unsupervised young children after school -- to the nation and calculated that "almost 1.2 million homes in the nation combine the risk factors of a firearm in the home and an unsupervised child."

The estimate was reported by Roberta K. Lee and Jeffrey J. Sacks in a letter to the Journal of the American Medical Association. "The mix of guns in the home and unsupervised children can be deadly," they wrote.

The researchers said they suspect their estimate is low, because some people responding to the survey might be "unwilling to admit either that they own a firearm or that their children are ever unsupervised." Also, the survey was limited to people 18 and older, while parents younger than 18 may be even more likely to leave their children unsupervised.

They suggested that parents and other caretakers be educated about how to protect children from weapons at home.

"Beyond storing weapons in locked boxes," Lee and Sacks wrote, "approaches such as trigger locks, childproof safety catches and loading indicators also may be important ways of reducing firearm deaths."