PHILADELPHIA, Pa. – Within a series of unfinished walls, Tom Stefanko oversees hundreds of construction workers every day, all of them wearing what looks like an old-school pager. Yet, the technology involved is new.

“I think it gives workers a little bit of comfort,” Stefanko said.

The devices are proximity tracers, designed to make sure workers on construction sites remain socially-distant during these pandemic times.

“If I was in contact another person, it would start beeping red,” Stefanko said. “And if I stayed there longer, it progressively beeps louder.”

While they alert workers that they’re too close to one another, the proximity tracers also record that data, in case a worker later ends up testing positive for COVID-19.

“It provides the ability to have a real-time alerting system and then also be able to go back historically and see who's been in contact with whom to do the contact tracing,” said Robert Costantini, CEO of Triax Technologies.

The company began to develop the proximity tracers when the coronavirus outbreak began.

“The stakes are really high, if you get it wrong,” Costantini said. “I mean, workers could be infected. You can shut your site down. The cost can be enormous.”

The contact tracers, though, cost about a dollar a day, per worker. More than 15,000 of them are now in use on more than 70 construction sites around the country, including the 1 million square foot building that Tom Stefanko and his team are working on in Philadelphia.

“We have a thousand tags here on site,” Stefanko said. “Most workers just keep it on their hardhat. And take it with them as they come and go – so, making it as part of their PPE.”

It’s personal protective equipment that is now a requirement to try and keep COVID-19 out of their workforce.