BOSTON — Massachusetts already has one of the nation’s strictest weapons-storage laws, but some gun control advocates want to make it even tougher.

A question proposed for the 2020 ballot would require gun owners to lock up their handguns, rifles, shotguns and ammunition in a “certified” safe. It would also hold gun owners legally responsible for “crimes committed by any person using unsecured weapons” taken from their home, vehicle or business.

Kirby Boyce, a West Roxbury resident who filed the petition, said a spate of mass shootings, as well as murders involving stolen firearms, illustrate the need for tighter rules.

“Kids are getting killed every year, and nobody is doing anything. This is something I can do,” said Boyce, who said he supports the right to own firearms.

Massachusetts is the only state that requires guns to be stored in a locked container or equipped with a tamper-resistant trigger lock or other safety device.

Gun control advocates note that wouldn’t prevent a gun owner, for example, from keeping a loaded weapon in a side table next to a bed.

“It means someone can keep a loaded weapon under their pillow, if they want to,” said John Rosenthal, co-founder of the Massachusetts-based Stop Handgun Violence, which supports tough gun control laws. “It would be safer if that weapon was kept in a safe.”

Rosenthal said gun control groups aren’t directly involved with the initiative but generally support tighter weapons-storage laws.

Gun rights groups argue the change would be unnecessary because the state already requires weapons to be secured and responsible gun owners follow the rules.

“I don’t think this is warranted,” said Jim Wallace, executive director of the Gun Owners Action League of Massachusetts, an affiliate of the National Rifle Association.

Buying a certified gun safe, which can run $2,000 or more, would be a hardship for many guns owners, he noted.

“That’s an expense that many people can’t afford,” he said.

The proposed question would give gun owners a six-month grace period to purchase a safe, and the cost could be deducted from their state income taxes.

If the Attorney General’s Office certifies the question, supporters would still face several hurdles to put it on the 2020 ballot – including gathering signatures of 80,239 registered voters.

Gun control advocates have long argued that many of guns sold illegally and then used in crimes had been stolen from private homes or businesses.

State and local police reported at least 1,127 firearms lost or stolen from 2016 to 2017, according to the Massachusetts Executive Office of Public Safety and Security.

The portion of crimes involving stolen guns recovered by police jumped from 9.7 percent in 2016 to 13.6 percent in 2017, according to the agency.

“The majority of gun accidents, teenage suicide and a lot of crimes happen with stolen guns that are left unlocked and accessible,” Rosenthal said.

To be sure, Massachusetts already has some of the toughest gun control laws in the country, such as real-time license checks for private gun sales and stiffened penalties for gun-based crimes.

Five years ago lawmakers gave police chiefs the authority to deny firearms identification cards to buy rifles or shotguns to anyone whom they feel is unsuitable.

Last year, the state approved a “red flag” law allowing a family member or acquaintance of a gun owner to ask a judge to temporarily confiscate that person’s firearms if they are deemed a danger to themselves or others.

At least 20 such petitions have been filed with courts since the law went into effect, according to state data.

Gun rights advocates say tougher rules haven’t reduced gun violence, citing dozens of homicides in Massachusetts committed with firearms so far this year.

Christian M. Wade covers the Massachusetts Statehouse for North of Boston Media Group’s newspapers and websites.