This story has been updated to properly reflect data contained within the 2018 State Child Fatality Advisory Committee report.

Roughly a quarter of child fatality cases reviewed by state authorities involving unexplained deaths from 2010 to 2017 involved unsecured firearms, according to a 2018 report from the State Child Fatality Advisory Committee.

The committee is tasked with reviewing child death investigations that law enforcement officials have closed. Of the 238 sudden or unexplained child deaths detailed in the report, 66 involved unsecured firearms leading to accidental firearm discharges, homicide or suicide, the committee's analysis showed.

In a country with almost as many guns as there are people, it’s not unusual to find loaded weapons within children’s reach. One study published in 2008 in the journal Health Education Research found that firearms are present in about one-third of all homes with children.

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In South Carolina, guns in half of those homes were kept unlocked and loaded, according to the South Carolina Victim Assistance Network.

"Unfortunately we see over and over that an adult's irresponsible choice to leave a loaded gun unsecured results in tragedy," said Beth Joslin Roth, co-founder of the Children's Firearm Safety Alliance.

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Roth started the alliance with Missouri state Rep. Stacey Newman in part to educate the public on how to keep children safe from guns.

"While the majority of gun owners are responsible and understand the importance of safely storing their guns, many assume that either their child doesn't know where they store their guns or that simply telling a child not to touch their gun will prevent them from doing so," Roth said in an email.

The accident that killed 2-year-old Kayden Stuber in Greenville is not unlike others that have happened across the nation. On June 20, officers responded to a home on Dronfield Drive, where they found a little boy covered in blood. He had shot himself in the face, according to the coroner.

The boy’s grandfather, Tim Gunter, said Kayden unzipped his grandmother’s purse, pulled the teal-colored handgun out of its holster and pulled the trigger.

"The only thing that I kind of regret in my life is that I got her a teal gun that looks like a toy," Gunter later said. "Probably the worst thing I could have ever done in my life when I think about it."

In North Charleston, two young children recently died under similar circumstances.

On June 10, police responded to Ranger Drive in North Charleston, where they found 5-year-old Zy’Ashia Smalls covered in blood and lying on her back on the living-room floor, the Post and Courier reported. She had suffered a gunshot wound to the chest.

An investigation determined that at least three other children, including a 12-year-old boy believed to have shot the girl, were inside the home unsupervised at the time.

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Three months earlier, at a home just two blocks from where Zy'Ashia lived, police responded to a similar scene. North Charleston officers said a 6-year-old accidentally shot his 1-year-old brother after finding a gun in a drawer that also contained candy, according to local media reports.

Taj Clark-Sparkman was taken to MUSC, where he remained hospitalized until dying of his injuries on June 22.

The boys’ cousin, Redante Young, 37, was charged with possession of a firearm by a convicted violent felon.

Kent Dill, a senior deputy coroner with the Greenville County Coroner's Office and a member of the State Child Advisory Committee, said shooting deaths involving children tend to happen more in the summer months when children have less adult supervision.

To help prevent these deaths, gun owners should secure all firearms under lock and key and store ammunition separately, Dill said.

"Never leave firearms and/or ammunition within the reach of children," he said.

Among children killed by guns in South Carolina since 2017:

► A 3-year-old in Aiken County who shot himself in the chest with one of two guns police found in the room.

► A 4-year-old girl in Spartanburg who was shot and killed by her 6-year-old brother with a gun he found in their house.

► A 3-year-old who shot himself with a gun he found in his family’s SUV in Anderson County.

► An 8-year-old in Orangeburg County who shot himself with a gun that his father kept in their car.

► A 2-year-old who shot himself with a gun he found in his Columbia-area home. His father then took his own life.

Nationally, more than 240 children have been shot and killed by other children since 2017, according to the Children's Firearm Safety Alliance.

Staff writer Daniel Gross and Nick Penzenstadler at USA TODAY contributed to this report.