Is this legal?

So, at my husbands job (nothing too wild just a printing warehouse also nothing secretive being printed) the employees are not allowed to be on phones but suddenly this week no one in the facility gets service/signal on their cellphones. Supervisors and the higher people do because they have the WiFi code, But as soon as you walk into the break room or out into the parking lot your device service returns. It’s seems like they placed jammers or blockers. I get it they don’t want folks on their phones but what if there’s an emergency? I called my husband the other day and he never received the call and his phone sent me to voicemail that he has Verizon but we have sprint?