SEATTLE — A 3-year-old boy fatally shot himself with a gun he found in a car while his family stopped for gas early today in Tacoma, police said. It was western Washington’s third recent shooting by a child.

“It is incredible in light of the other ones,” said Tacoma police Officer Naveed Benjamin. “You would think people would take more care, not less.”

The Tacoma-area family had stopped for gas about 12:30 a.m. The father put his pistol under the seat and got out to pump gas while the mother went inside the convenience store, Benjamin said.

They left their son and their infant daughter in the car. The boy climbed out of his child seat, found the gun and shot himself in the head, police said. He was declared dead at a hospital. The girl was not injured.

Detectives questioned the parents and have called the shooting a tragic accident, Benjamin said. The father has a concealed weapons permit, and no charges are anticipated, he said.

Washington does not have a law specifically concerning child access to firearms.

The shooting follows the death of the 7-year-old daughter of a Marysville police officer in Stanwood on Saturday when a sibling found a gun and fired while the parents were out of their car. And on Feb. 22, an 8-year-old girl was critically wounded in a Bremerton classroom when a gun fired inside the backpack of a 9-year-old boy as he put it on a desk.

“It’s another tragedy in a very short period of time,” Benjamin said.

It highlights the need for people to secure guns, he said.

“You can’t predict what children are going to do,” he said. “You need to unload and lock it up if you’re not carrying it. … It’s really not that hard to practice firearm safety.”

Twenty-seven states have some form of law to prevent child access to firearms, but Washington is not one of them. Such laws can include criminal penalties for adults who allow children to get their hands on guns, according to the San Francisco-based group Legal Community Against Violence.

State lawmakers considered a measure in the regular legislative session that ended Friday that would have required additional testing of gun locks and safes before the equipment is distributed to law enforcement officers for home use. The bill was prompted by the 2010 death of a Clark County deputy’s 3-year-old son. The toddler took a gun from a department-issued safe, which the family insisted was faulty.

News of the latest shooting caused Washington Cease Fire Executive Director Gregory Roberts to groan, “Oh no.”

“We think guns are dangerous, but they are not treated as dangerous by our society or by laws or by our regulations,” he said. “We regard guns as some sort of sacred object that should not be subject to regulation.”

The Seattle organization is currently running a campaign of ads on buses urging people to think twice about owning guns. People with guns in their home or car are more likely to injure or kill a family member or loved one than to use it against an intruder, he said.

“Unfortunately we’ve been saying the same thing over and over because we see the same thing happening over and over,” Roberts said.

In Saturday’s shooting, off-duty Marysville police Officer Derek Carlile had parked the family van near Stanwood City Hall, and he and his wife were out of the vehicle when one of their children found the loaded gun and fired. The shot hit 7-year-old Jenna Carlile, and the girl, the oldest of their four children, died Sunday at a Seattle hospital.

The 8-year-old Bremerton girl, Amina Kocer-Bowman, remained in serious condition at Harborview Medical Center in Seattle after nearly dying in the accidental shooting at Armin Jahr Elementary, where a classmate brought a handgun to class. Authorities believe the boy took the .45-caliber gun from the glove compartment of a car while visiting his mother and her boyfriend at their home. He lives with an uncle.

The 9-year-old pleaded guilty last week to reckless endangerment and was sentenced to probation and counseling. He is expected to testify against his mother, Jamie Lee Chaffin, and her boyfriend, Douglas L. Bauer, who were charged Tuesday with felony assault.

Chaffin and Bauer each could face up to five years in prison if convicted.