The 19 firefighters who showed symptoms of “having a serious exposure to a confirmed COVID-19 patient” in King County, Washington, have been moved to isolation, according to Doug Stern, president of the International Association of Fire Fighters.

These 19 firefighters are part of the 25 CNN reported earlier were in quarantine after responding to calls at the Life Care Center nursing facility. All are firefighters with the Kirkland Fire Department.The remaining firefighters will remain in quarantine.

According to the Centers for Disease Control and Prevention, isolation separates sick people with a contagious disease from people who are not sick. Quarantine separates and restricts the movement of people who were exposed to a contagious disease to see whether they become sick.

Stern said that while most of the isolated firefighters are showing symptoms, a few of the firefighters are being isolated only because of their exposure.