It was reported at 12:07 p.m. on the second floor at the 350 Oxford Road facility in Mansfield Township, according to township police Chief Michael Reilly.
It occurred in Room 243, which was unoccupied at the time and in an unoccupied wing, said Warren County Fire Marshal Joe Lake.
No one was injured, and the cause of the fire remained under investigation by township police, Lake and the Warren County Prosecutor’s Office.
Upon activation of a fire alarm, staff initiated their evacuation protocol, police said. Residents there were allowed to remain inside, behind closed doors, according to Lake.
Firefighters vented smoke from the building, and residents were allowed to go about their day, police said.
Responding to the incident along with township police, Lake and the prosecutor’s office were the Mansfield Township Fire Department, Tri-County Fire Department, Oxford Township Fire Department, Independence Township Fire Department, Oxford Rescue Squad, Washington Borough Rescue Squad, Hackettstown Rescue Squad and Warren County Hazmat.
Privately owned, Warren Haven says it offers respite, short-term sub-acute rehabilitation and long-term care stays, as well as a secured memory care unit.
The facility was fully operational immediately following the incident and is working with local officials and the New Jersey Department of Health to investigate what happened, Warren Haven CEO Amy Austin said in a statement.
“Warren Haven remains committed to providing a safe environment of care for all of its residents/patients, employees, families, and visitors, and will continue to follow the guidance of the New Jersey State Department of Health and local authorities as necessary and appropriate,” Austin stated.