In this Thursday, Sept. 14, 2017, photo students head for their buses at York Middle School in York, Maine. Credit: Robert F. Bukaty / AP

The state says it’s unsafe for schools in another Maine county to have its schools open full time.

The Maine Department of Education on Friday said it has moved Oxford County into “yellow” territory, meaning it’s only safe for schools in the county to be open in person part-time. Oxford County joins York County, which has had a yellow designation for the past three weeks as the southernmost county has seen a number of outbreaks and a spike in coronavirus cases traced to an Aug. 7 wedding in the Katahdin region.

The Department of Education on Friday also said it planned to keep close tabs on Androscoggin County and reevaluate weekly whether it’s safe for schools there to be open full time.

Even though 14 of Maine’s 16 counties are considered green, meaning they have clearance to reopen in person full time, most Maine schools are employing a hybrid model this school year in which students learn remotely part of the week and attend in person the rest of the week. The other color-coded rating, red, means it’s unsafe for schools to be open in person at all.

Oxford County, in western Maine, has emerged as another area in Maine where the coronavirus is actively spreading in recent weeks, with an outbreak at the ND Paper mill in Rumford where 23 people had tested positive as of Thursday and one employee had died.

A handful of schools in the county have also reported cases with the fall semester getting underway.

Schools in Canton, Carthage, Dixfield and Peru, which make up Regional School Unit 56, temporarily closed last week after multiple positive cases of COVID-19. The district will remain closed until next week.

RSU 56 shut down schools last Monday, following the closure of the Region 9 School of Applied Technology in Mexico where a student tested positive for COVID-19.

Oxford County’s rate of coronavirus tests coming back positive over the past two weeks — 2.1 percent — is more than four times the rate for the rest of the state, which is 0.5 percent. The positivity rate is a key indicator of how actively the virus is spreading in a particular area.

Oxford County has also seen the highest rate of new COVID-19 cases in the state over the past two weeks, with 10.69 cases for every 10,000 residents in that period, compared with 3.44 for all of Maine.

Those indicators have also started to rise in Androscoggin County in recent weeks. It’s recorded 6.37 new cases for every 10,000 residents over the past two weeks to the state’s 3.44. And it’s test positivity rate was 0.7 percent.

One Androscoggin County town, Turner, has seen one of the highest rates of growth in the number of cases for every 1,000 residents over the past several weeks. This week, schools in that town temporarily switched to all-remote instruction after a handful of related COVID-19 cases.