Syracuse University’s wastewater surveillance program has detected “very weak” traces of the coronavirus in Sadler Hall, the university announced Friday. 

The announcement comes a day after SU’s wastewater testing program identified potential traces of COVID-19 in Ernie Davis Hall, which began a quarantine for all residents there. All COVID-19 tests from residents and employees of Ernie Davis came back negative on Friday, ending the quarantine.

The traces of COVID-19 in Sadler differ from the virus signal in Ernie Davis, which was “consistently present and more pronounced,” Vice Chancellor Mike Haynie said in a campus-wide email.  The presence of COVID-19 in Sadler’s wastewater could have resulted from students in the building who recently recovered from the virus, Haynie said.

SU plans to test all Sadler residents and employees Friday at testing stations on the Quad, but will not require them to self-quarantine. The university will also continue to monitor the wastewater from the residence hall, Haynie said.

The university has also tested and found no traces of COVID-19 in wastewater at Lawrinson, Flint, Day, Shaw and Walnut Hall.

“I recognize that any virus detection stemming from our wastewater surveillance program — weak or strong —will create some anxiety and may result in disruption to daily routines or schedules,” he said. “However, this program is a critical dimension of the system of protections in place to support quick action in response to any potential infection on our campus — and it is working exactly as intended.”