Hundreds of young children in the U.S. have been killed playing with guns over the last two decades, according to a study published Thursday by the Centers for Disease Control and Prevention. The vast majority of cases involved guns that were stored unlocked and loaded.

The CDC report’s authors say their new findings highlight the rising toll taken by accidental gun deaths that could be preventable.

“Securing firearms (e.g., locked, unloaded, and separate from ammunition) is protective against unintentional firearm injury deaths among children and adolescents, underscoring the importance of promoting secure firearm storage,” reads the study, which was published in the agency’s Morbidity and Mortality Weekly Report.

For the study, federal researchers examined 1,262 accidental firearm deaths reported from 2003 to 2021 to the CDC’s National Violent Death Reporting System, which links death certificate tallies to other data from law enforcement investigations.

Of them, the CDC’s report narrowed in on 367 accidental gun deaths of children ages 0 to 5 years old and 176 deaths of children 6 to 10 years old. 

Unintentional firearm deaths made up around a quarter of all firearm deaths over this time period in children under 10 years old, according to other CDC data. That CDC database tallies 82 unintentional gun deaths of children up to 10 years old in 2021, the most in a single year reported across the U.S. over the past two decades.

Firearm deaths overall have also risen as a cause of death in kids, after a steep increase especially in teens ages 15 to 19 starting in 2020.

Accidental gun deaths at home

For all age groups of children through 17 years old, the report found that accidental gun deaths were most likely to occur in a house or apartment. Eight in 10 such incidents took place in a home; 56% happened in the child’s own home.

Among the youngest age group, kids 0 to 5 years old, more than half of unintentional firearm deaths were found to be self-inflicted by the child. Among those accidentally killed by others, more than half were from other children ages 10 and under. 

Around 2 in 3 gun deaths in this age group were from playing with the firearm or showing it off to others. In 99% of all reported deaths in this age group, the gun had been stored both loaded and unlocked.

Accidental gun deaths in the next oldest group of children, ages 6 to 10 years old, were more likely to be inflicted by someone else. Nearly half of accidental gun deaths in this age group were at the hands of shooters who were between 11 and 17 years old.

Similar to accidental gun deaths of the youngest kids, nearly 2 in 3 of deaths of kids ages 6 to 10 years old were also from playing with the firearm or showing it off to others. 

“These findings underscore the fact that parents’ reliance on children’s ability to distinguish between real and toy firearms and to not handle a firearm if they encountered one is insufficient to prevent unintentional firearm injury deaths of children,” the study’s authors wrote.

More than 8 in 10 deaths in this age involved guns that were stored both loaded and unlocked.

In a third of accidental gun deaths in kids ages 0 to 5 years old and more than a quarter of kids ages 6 to 10 years old, the guns had been stored on a nightstand or bed.

The new findings come at a time when gun owners with children are now more likely to safely secure their firearms at home, compared to previous years. 

In separate survey results published last year, 44.1% of firearm owners with kids said they stored all their guns locked and unloaded at home during 2021, up from 29% in 2015.

However, the study also noted that a larger share of parents are also now owning firearms overall, effectively offsetting the increase in safer gun storage.

“As a result, our estimate of the number of children who lived in a household with loaded and unlocked firearms in 2021 (4.6 million) was not meaningfully different from the estimate reported in the 2015 National Firearms Survey,” that study’s authors concluded.