The school year was starting in 10 days, and Donald Keegan was a busy man. An associate superintendent of the North Syracuse Central School District, Keegan had to make sure the bus drivers were trained and the cafeterias fully staffed. He had a tour to lead that afternoon and a school board meeting in the evening.

But that late August morning, Keegan took time to attend a demonstration inside a local factory, where he observed a series of windows being obliterated by an AR-15-style rifle.

Keegan was joined by other school officials from central New York, a school custodian and a pair of school architects. They stood with their arms crossed as Tom Czyz, the founder of Armoured One, a company that sells protective glass and film, fired more than 30 rounds at a window at close range. The room shook with skull-rattling force. By the end of the presentation, Czyz’s arms were speckled with shards of glass and dripping with blood.

“It’s sad, really,” Keegan said later in an interview. “But it’s part of our job to make sure kids don’t get shot. That is part of the current reality.”

Of all the troubling aspects of gun violence, among the most dispiriting may be scenes like the one in the Syracuse, New York, glass factory: Preparing school administrators for a mass shooting is becoming routine.

Rising gun violence, punctuated by massacres such as the attack at the elementary school in Uvalde, Texas, last year and the shooting on Michigan State University’s campus last week, is fueling not only the debate over gun control but also a more than $3 billion industry of companies working to protect children or employees against mass murder.

The offerings are numerous: automatically locking doors, bullet-resistant tables, Kevlar backpacks, artificial intelligence that detects guns and countless types of training exercises, like breathing techniques to avoid panic during an attack or strategies for how to use a pencil to pierce a shooter’s eyes.

But even as Congress increases funding for school security measures — including $300 million to help schools “prevent and respond to violence” as part of a bipartisan gun control compromise — the effectiveness of the school security industry’s products and services remains largely unproven.“This is an entire industry that capitalizes on school shootings; however, these companies have very little evidence that what they are selling works,” said Odis Johnson, the executive director of the Johns Hopkins Center for Safe and Healthy Schools and a Bloomberg distinguished professor at the university. (Billionaire Michael Bloomberg, an alumnus, has been a major supporter of gun control efforts.)

Schools and apartments have to be built to withstand fires and earthquakes, and the Occupational Safety and Health Administration issues fines for hazardous working conditions. But there is no equivalent of rigorous and standard monitoring of whether an employer is reasonably prepared for an active shooter.

This regulatory netherworld, industry executives say, is partly the result of the nation’s political paralysis over guns. Many say protective windows and backpacks would not be necessary if guns, particularly military-style rifles, faced more restrictions. Creating standards for school security against guns, some believe, would be seen as giving in to the notion that mass shootings are a part of American life, that they can be defended against but not eliminated.

Czyz said political leaders who did not support stepping up security measures at schools — or “hardening” them — were naive. “If you aren’t for hardening the schools, then unlock your front door, unlock your windows and let whoever in,” he said. It typically costs about $350 to install an Armoured One protective window in a classroom door, which Czyz said could slow down someone trying to shoot his way into a locked room.

With each new mass shooting, more schools and businesses, even in parts of the country that support stricter gun control, are taking steps to bolster the security of their buildings and train their staff. In a survey of more than 1,000 public schools last year by the National Center for Education Statistics, a research arm of the Education Department, the majority said they were taking some measures, such as putting locks on doors, to defend against shooters. As the threat of violence grows, so is the industry that is offering ways to stop it.

An industry gathers to show off its products.

In one measure of how school shootings have become normalized, the industry holds an annual conference — meeting last summer in Orlando, Florida, just like dairy farmers, golf course managers and tax lawyers did over the past year.

At the Omni Orlando Resort, the National School Safety Conference attracted dozens of businesses selling a wide range of products, from locking devices for classroom doors to a series of “ballistic” tables meant to be used as shields. The participants included law enforcement agents and educators.

Most of the vendors were small operators, but there were a few larger companies like Navigate360 and Raptor Technologies, whose security app was used by the Uvalde School District to alert employees that an active shooter was in the elementary school. But even after a Uvalde school employee used the app, the gunman was able to enter classrooms and carry out the shooting while police officers waited to confront him, which led to more deaths.

The failure of the law enforcement response in Uvalde hung heavily over the conference because many of the technologies and products on display were designed to buy time before the police can arrive. If the police fail to take further action, many of the products cannot ultimately help.

‘Trying to change the way people live’

Some business owners in the active-shooter-defense industry say they are not just selling products but preparing people to defend themselves.

One of them is Ken Alexandrow, a former police officer in Tennessee who runs Agape Tactical, a company that has taught nurses, teachers and church staff techniques for defending against a shooter. His basic sessions cost $1,000.

“We are trying to change the way people live in society,” Alexandrow said over breakfast while visiting New York to discuss his classes with a company that provides unarmed security guards for businesses. “We want to make people responsible for themselves and stop acquiescing security to someone else.”

He said that many training companies focused on teaching people how to run or hide from a shooter, but that meeting violence with violence was also effective. “Fighting works,” he said.

Alexandrow started by training employees and volunteer security guards at churches around the South. These students tended to be older men who were familiar with firearms.

More recently, Alexandrow has branched out into health care and day care.

On his laptop, he played a video of day care workers pouncing on and punching him as he walked through a building in a red padded suit, carrying a fake rifle.

Alexandrow has also trained people how to “drive” a pen, a pencil or a set of keys into a shooter’s eyes and into the brain.

“If they are squeamish, we tell them, ‘Think about what the shooter has in store for you,’” he said.