Denver residents this week once again heeded a warning they may not have needed to.

Tornado warning sirens were activated in Denver on Monday afternoon, which came as reports of heavy thunderstorms and hail were making their way through the Denver metro area.

Some areas of Colorado, east of Denver, were also under a tornado watch, adding credibility to the alarms being sounded in Denver.

However, the alarms in Denver were sounded by mistake, Denver’s Office of Emergency Management said Monday. Following a “comprehensive review,” the OEM has determined the alarms going off was a result of human error, not a technology failure or malfunction of the sirens.

In a statement, OEM said the human error was an “improper understanding of protocol.” 9NEWS has reported that a 911 caller reported a tornado, causing a Denver Fire Department employee to activate the sirens without following proper verification procedures.

“While the siren system functioned as designed, the activation itself was not warranted as there was no tornado warning in effect for Denver at the time,” said Loaitza Esquilin Garcia, communications manager for OEM.

According to 9NEWS, the standard protocol for activating the sirens requires for the National Weather Service to issue a tornado warning for the area. At the time of the sirens being issued, Denver was under a tornado watch, meaning a tornado was possible, not a tornado warning, which means a tornado has been spotted.

The siren activation is the latest in a string of inadvertent emergency notifications issued in Denver.

The Denver Police Department has previously issued emergency alerts to the whole city when the alerts were meant for a small area near where active police incidents were happening.

Garcia said Denver is looking to implement operational improvements regarding how alarms are activated. The city is planning a comprehensive review of alerting policies and procedures, and officials plan to enhance training and exercises for those involved in issuing emergency alerts.

“The City and County of Denver recognizes that emergency alerts are intended to prompt immediate action during potentially life-threatening situations, and any unintended activation is a serious matter,” Garcia said. “We have a responsibility to provide residents with timely, accurate, and reliable emergency information, and we are committed to continuously improving our processes to ensure that responsibility is met.”

The Denver Gazette’s news partner 9NEWS contributed to this article.