Tennessee lawmakers passed a bill on Tuesday to allow teachers and other school staff members to carry concealed handguns on school campuses. The measure, if it becomes law, would require those carrying guns to go through training and to have the approval of school officials, but parents and most other school employees would not be notified.

The bill is one of the most significant pieces of public safety legislation to advance in Tennessee after a shooting just over a year ago at a private Christian school in Nashville left three students and three staff members dead. The attack galvanized parents at the school and many others in Tennessee — including the state’s Republican governor — to demand action that could prevent similar violence.

But many of them believed that restricting access to guns was the solution, and critics of the legislation have argued that bringing more weapons onto school campuses would not improve safety and could even amplify the danger facing students.

Protesters opposed to the bill packed the House chamber and the corridors of the Capitol on Tuesday, carrying signs that said, “Kids Deserve More!” and “Have You Lost Your Ever-Loving Minds?”

The demonstrators echoed fears that have been raised since the legislation was proposed.

“I ask that you don’t put our children’s lives at risk by putting more and more guns in schools,” State Senator London Lamar, a Democrat from Memphis, said during a debate this month as she cradled her infant son. “It is really hard,” she added, “even as a new mom, to stand here and have to be composed on a piece of legislation that I know puts my son’s life at risk.”

The bill’s supporters have disputed that contention, arguing that the measure would protect students, not only because trained adults would have access to guns but also because their presence could act as a deterrent to a would-be assailant.