There appears to be no statistics keeping track of how many U.S. children fire a gun and intentionally or unintentionally harm someone. Yet, for many it feels like a month doesn't go by that we don't hear about a child pulling the trigger and killing someone with a firearm. These incidents have added fuel to the gun control debate. (Claritza Jimenez/The Washington Post)

Early last month, a 2-year-old Florida boy found a gun in a vehicle and shot himself with it. A few weeks later in Flint, Mich., a 3-year-old boy found a 9mm handgun and fatally shot himself in the head. And just this past weekend, a 3-year-old Alabama boy found a gun on a nightstand and fatally shot his 9-year-old sister, Kimberly Reylander, with it.

Aside from the age of the children involved, these cases all have one thing in common: They involved guns that belonged to a grandparent or great-grandparent, or they happened in a grandparent's home. The Florida boy, Ethan Walker, was in his grandfather's truck when he shot himself. The Flint boy was at his great-grandparents' house when he got his hands on a gun. So was the boy in Alabama.

In another recent case, a 3-year old was shot and killed while sleeping in his grandmother's bed after a gun she kept under her pillow discharged. Last month in Texas, a 4-year-old boy staying over at his grandparents' house found a gun and shot himself in the head. In Missouri, a 5-year-old girl shot herself after finding a gun that her grandmother tried to hide by sliding under a couch.

All told, in the first five weeks of this year at least six children age 5 or under have shot themselves or someone else either in a grandparent's home, or after finding a gun that belonged to a grandparent.

Children are generally safer under the care of a grandparent. In 2008, for instance, a Johns Hopkins study found that children are typically less likely to injure themselves while in the care of a grandparent than while under supervision of day-care workers, other relatives or even nonworking mothers.

But the shooting cases underscore the importance of keeping guns locked up even if you don't have small children in your own home. Twenty-seven states plus the District have "child access prevention" (CAP) laws on the books that impose penalties on people who negligently leave their guns in places where kids can find them.

Research shows that these laws work. A 2005 study found that in 10 states, the laws prevented 829 injuries in 2001, saving $37 million in medical costs. A study in the Journal of the American Medical Association in 2004 found that CAP laws prevented 333 teen suicides between 1989 and 2001.

Considering the proliferation of firearms in this country -- more than one gun for every man, woman and child -- a certain number of accidents like these are to be expected. People get careless and they forget things -- even important things, like their guns. Just look at the increasing numbers of people who absentmindedly attempt to bring loaded handguns on airplanes.

CAP laws are less about punishing negligent gun owners after the fact and more about nudging responsible ones to prevent something terrible from happening. Laws help shape societal norms. If six little kids have been able to get hold of grandpa's gun and shoot someone with it this year, it suggests that many folks have a dangerously casual attitude toward leaving loaded guns out in the open.

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