When a gunman opened fire in the Old National Bank in Louisville, Kentucky yesterday morning, killing five and injuring several others, it became the 15th mass killing with four or more deaths so far this year. The alleged gunman, a bank employee, was brandishing an AR-15.

John Rosenthal, co-founder of the advocacy group Stop Handgun Violence, said on Greater Boston that a handful of Republicans in Congress are blocking passage of universal background checks for gun purchases that could prevent easy access to weapons like these.

“We are killing our future generations because the Republican party is more concerned with blood money campaign contributions from the uniquely unregulated gun industry then they care about our families and our children and our neighbors,” said Rosenthal.

Unlike other consumer products, Rosenthal said no federal standards or safety regulations exist for guns.

According to a 2021 Pew Research study, 53 percent of Americans support stricter gun laws, but that is divided along party lines, with 81 percent of Democrats favoring tighter restrictions.

“Nothing is going to change overnight," said Rosenthal. "When Congress doesn’t care that the leading cause of death among children is firearms, you know we’re in trouble."

Massachusetts has strict gun restrictions and one of the lowest gun death rates in the country. Rosenthal said every state should adopt similar legislation to implement background checks and ban assault weapons.

Rosenthal said he remains optimistic that Gen Z and millennials will replace the politicians currently in office and be able to make a difference.

Watch: Five killed at Kentucky bank in America’s latest mass shooting. What will it take for lawmakers to act?