Several Cobb County schools were locked down Monday due to “human error,” a district spokeswoman confirmed.

The spokeswoman did not say which schools were affected, but parents from multiple schools said on social media they received similar messages about accidental lockdowns.

“Earlier today, and through human error, one of our staff members accidentally triggered a Code Red at multiple campuses,” the district said in an emailed statement to The Atlanta Journal-Constitution. “At no time was there any threat, nor were any of our students or staff in danger.”

The issue is being treated as a personnel matter, the statement said.

At least one school had a similar problem last week. Families at Durham Middle School in Acworth were notified on Thursday that a staff member “inadvertently triggered a Code Red,” according to a message obtained by the AJC.

“This was not a malfunction, but simply an instance of human error,” the message from Principal Andy Bristow said.

The district this year implemented a new crisis alert system that allows employees to trigger a lockdown in the case of an emergency. The district has spent about $3 million on the implementation of the Centegix crisis alert system this year, the AJC reported last month.

Cobb schools previously spent about $5 million on the implementation of a different system, called AlertPoint. That system triggered a lockdown at all of the district’s schools when no threat was present in 2021. District officials first called it a “malfunction,” and later, a “targeted, external attack.”

Employees were trained on how to use the Centegix system earlier this year. They received badges with buttons on them that can initiate different alerts with different levels of responses.

Accidental activations are some of the potential problems with crisis alert systems, security experts warn.