SALEM — The Oregon Office of Emergency Management says that it failed to do a manual override that would have prevented the vague and clipped emergency message that went out to many Oregonians’ cellphones Tuesday night.

A local drinking water hazard alert intended for Salem and surrounding communities was truncated and changed to a generic “civil emergency” message late Tuesday night, prompting confusion until the state sent out a revised alert.

The message said a “Civil Emergency” was in place until 11:28 p.m. and instructed recipients to “prepare for action,” but did not specify the nature of the emergency or the action that would be required. The message was sent to phones across Marion, Benton, Linn, Yamhill, Clackamas and Deschutes counties, far beyond the area impacted by the water hazard.

About half an hour later, the agency sent out a correct and complete alert about the water issues.

The state sent out the message on behalf of Salem, which wrote the text of the alert.

Local officials had asked the state to send out an emergency alert after learning the drinking water supply from the Detroit Reservoir tested positive for toxic blue algae in levels that are hazardous for children, nursing and pregnant women and other people with certain health conditions to drink.

Cory Grogan, spokesman for the Office of Emergency Management, said Wednesday that he didn’t know how many employees were responsible for reviewing the alert before sending it out.

Paula Negele, another office spokeswoman, said that the department did not know that the manual override was necessary.

Alerts to cellphones are called Wireless Emergency Alerts, which are regulated by the Federal Communications Commission, and the state has no way of testing them, Grogan said.

Tuesday was the first time the state sent a Wireless Emergency Alert, Grogan said. He added that the FCC is planning improvements to the system.

In a video posted to Facebook Tuesday night, Office of Emergency Management Director Andrew Phelps said that the agency would conduct a forensic analysis of what happened.

“I apologize for the confusion and the anxiety this incomplete message has caused people,” Phelps said. “Beginning this evening, we are conducting a forensic analysis of the steps we took to send this message and to ensure our procedures are written and practiced in a way that will prevent confusing messages from being sent from our system in the future.”

Another, separate system, called the Emergency Alert System, notifies the public via broadcast over TV and radio.

That alert to TV viewers and radio listeners in the appropriate areas went out without a hitch, officials say.

Back in January, after a hubbub over an accidental alert warning of a ballistic missile threat in Hawaii, the state of Oregon said that the same thing couldn’t happen here because the state doesn’t use prewritten templates.

In Hawaii, an employee accidentally selected the wrong message from a menu of prewritten messages.

Grogan said late Wednesday that the agency has removed the default message and that it won’t be able to be sent again.

The Capital Bureau is a collaboration between EO Media Group and Pamplin Media Group.