Mars Area High School will be closed through Thursday, according to an announcement posted on the district’s website.

On Monday, district officials were notified of four high school students who tested positive for COVID-19 and are quarantining.

These were in addition to two cases reported earlier Monday, bringing the school total to six active cases.

With more than 900 students, Mars Area High School is considered a “large” school by the Pennsylvania Department of Education and Pennsylvania Department of Health.

The school is required to close at least three days when there are six to 10 positive cases. During that time, the building undergoes deep cleaning.

Once a school has undergone a deep cleaning, the number of active positive cases at that school reverts to zero, beginning with the first day students and staff return.

The state Department of Health is conducting contact tracing. Anyone who may have been in close contact with a positive case will be notified and required to quarantine for at least 14 days.

High school students may return to traditional instruction Friday, pending the district’s review of the school’s case numbers.