For months, immigrant advocates have feared the novel coronavirus was silently spreading at the Northwest detention center. The results of court-ordered testing have now come back, and all but one of 45o were negative, according to a Monday filing by federal authorities.

Not everyone was tested at the Tacoma facility because 111 detainees declined to give their consent, according to the filing.

The person who tested positive, who arrived at the detention center May 29, was initially held with one other detainee in a unit reserved for new arrivals and was transferred, after the positive test result, to a medical isolation unit. The detainee exposed to that person tested negative for COVID-19 but will still be held alone in a cell and under medical observation for 14 more days.

The findings appear to be a validation for Immigration and Customs Enforcement (ICE), which faces a proposed class-action lawsuit on behalf of vulnerable detainees seeking release. ICE and private contractor the Geo group, which runs the facility, have argued that  the population of the 1,575-bed Tacoma facility has dropped so much, to less than half its capacity, that detainees are able to socially distance. Officials have also described a number of precautions, including keeping new arrivals in separate units for 14 days to see if they develop symptoms.

Matt Adams of the Northwest Immigrant Rights Project, which along with the ACLU filed the lawsuit, was nevertheless skeptical of the results. He said there are questions about what test ICE is using, pointing to a Miami Herald report that immigration authorities are sometimes using a 15-minute rapid-test known to have false negatives.

An ICE spokesperson said tests are processed at commercial and public health labs but could not immediately say what kind was used.

“Even if they have somehow avoided transmission of the virus up until now, the point of our lawsuit is that where it appears more likely than not that our medically vulnerable persons will eventually be exposed to COVID-19,” Adams added.