BOULDER COUNTY, Colo. (KDVR) — The Boulder Valley School District says a male substitute staffer was potentially exposed to the new coronavirus 12 days ago while on a cruise that had “a small cluster” of cases.

He has not shown any symptoms.

In a Facebook post published Wednesday evening, the school district says the substitute has worked at Centaurus High School in Lafayette during the past five days.

He was not notified of the potential exposure until Wednesday. He alerted the school district immediately and went home, the school district said.

“Based on what we know about this disease to date, it is extremely unlikely that someone would transmit the virus without having symptoms. In fact, the CDC guidance states that as long as the person is not symptomatic they can continue to work, however, as a precaution, we will not be allowing the staff person to return to work until the 14-day exposure window has passed,” the school district said. “While we do not believe there is a significant risk of our students getting sick, we are dedicated to doing everything possible to protect our students and to keep you informed. BVSD has been updating resources about Coronavirus and staying healthy here.”

The school district did not announce any plans to close Centaurus.

More information about the virus is available on Boulder County’s website.

Earlier Wednesday, officials confirmed an employee at the Denver Federal Center in Lakewood was potentially exposed to the virus during a trip 12 days ago. Workers in that office have the option to work from home for the remainder of the week.

There are currently no confirmed cases of coronavirus in Colorado.