LANSING — Michigan on Monday launched the statewide rollout of a voluntary, free coronavirus app that notifies users if they have potentially been in close contact with infected people.

The announcement came more than three weeks after the state began piloting the technology in Ingham County, including at Michigan State University. More than 46,000 people downloaded MI COVID Alert onto their smartphones.

State Health and Human Services Director Robert Gordon urged all Michiganders to follow suit, especially as COVID-19 cases and related hospitalizations have surged after an initial wave subsided last spring.

“I would encourage folks — try it out, put it on your phone. I think you’ll see that it’s free, it’s easy, it doesn’t gob up a lot of battery,” he told The Associated Press. “Once you’re using it, then you get your friends and family to use it, too. If you do that, as a group you’re going to be a little bit safer.”

Those testing positive for the virus are given a PIN by contact tracers that allows them to share their result anonymously on the app, which uses Bluetooth technology and randomly generated phone codes. Other app users who possibly were within 6 feet (1.8 meters) of infected people for at least 15 minutes are notified.