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:

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.”

***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 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.