A York County school district has announced it’s delaying the start of classes by a week after someone associated with its transportation department tested positive for COVID-19 and after state officials warned last week that it’s not safe for schools in the southernmost county to fully restart in-person classes amid several different outbreaks of the disease.

In a letter posted online on Labor Day, Regional School Unit 57 announced that it was delaying the staggered start of remote and in-person classes to the beginning of next week. They had been scheduled to start this week.

Superintendent Larry Malone said the district had made the decision out “of an abundance of caution” after “an individual associated with the Transportation Department recently tested positive for” COVID-19.

Malone did not provide much additional detail about the relationship of that person to the district’s transportation staff, but he said that state health investigators — known as contact tracers — have classified that person as not a “close contact.”

RSU 57 includes the town of Alfred, the York County seat which also includes its jail. The jail is now trying to contain a COVID-19 outbreak that has spread to at least 75 people: 46 inmates, 22 workers and seven of their family members.

The school district also includes Waterboro, Shapleigh, Lyman, Limerick and Newfield.

Last week, state education officials downgraded the safety designation of York County schools from green to yellow, meaning it’s no longer considered safe for them to resume in-person classes full time. It’s the only Maine county that now has been moved out of the green status.

In addition to the jail outbreak, the state is also investigating a COVID-19 outbreak at Calvary Baptist Church in Sanford — one town over from Alfred — which has at least 10 confirmed cases and where Pastor Todd Bell continues to hold services. Bell also officiated the Aug. 7 wedding in the Katahdin region that sparked the state’s largest COVID-19 outbreak and was attended by one of the first York County jail employees to test positive.

And the state is still working to contain an outbreak involving multiple York County fire departments.

York County in recent days has emerged as a particular area of concern for the state, prompting the schools’ change from green to yellow. The county’s rate of new cases and its rate of coronavirus tests coming back positive have been about triple the rest of the state over the past two weeks. Nirav Shah, director of the Maine Center for Disease Control and Prevention, said Thursday that half of the state’s active virus outbreaks are in York County. The county has also seen a spike in cases not connected to the known outbreaks in the county, suggesting that the virus is spreading in the community.