It wasn’t a test, but it wasn’t a real emergency broadcast, either.

On Tuesday evening, TV viewers in parts of southern New Jersey saw a sudden -- and no doubt alarming -- warning flash across their screens, right in the middle of primetime:

***FALSE EMERGENCY ALERT*** You may have seen this message on your TV tonight.There is NO emergency. This message went out in error #ReadyNJ pic.twitter.com/qzh0l9rZ03 — NJOEM (@ReadyNJ) May 24, 2017

The New Jersey Office of Emergency Management said the “nuclear power plant warning” was created as part of a training exercise.

“The message was intended for a small group of emergency management personnel who were participating in the exercise,” the agency said. “As a result of a coding error, the message was publicly broadcast.”

The message went out to TV viewers in Salem County, home of the Salem Nuclear Power Plant, and neighboring Cumberland County. The two counties have a combined population of around 215,000 and are not far from both Philadelphia and Wilmington, Delaware.