A Colorado prison is now the site of the state’s largest confirmed COVID-19 outbreak as mass testing confirms that 238 inmates at Sterling Correctional Facility have the virus.

The number of positive cases at the facility spiked as more results from the 472 tests administered last week became available. Of those tested, half were positive. Sixteen tests were inconclusive, 216 were negative and two were still pending Tuesday afternoon, Colorado Department of Corrections spokeswoman Annie Skinner said in an email.

Four of the sick inmates were in the hospital Tuesday afternoon, Skinner said.