New London — School officials said that, on the eve of school opening, they addressed a mold issue at Nathan Hale Arts Magnet School first noticed by staff last month.

Nathan Hale opened as planned with the rest of the district on Thursday.

The presence of mold was confirmed by tests conducted by Mystic Air Quality Consultants on Aug. 31. A Sept. 9 report by the firm showed three rooms with elevated mold levels.

Those areas have since been cleaned and some items, such as cloth music cases and ceiling tiles, were removed. The cleanup work started before test results were known and completed on Wednesday after staff was sent home early.

Two of the rooms remained closed off Thursday “out of an abundance of caution” until follow up air quality tests are performed, said Kate McCoy, the district’s executive director for strategic planning. The rooms included a music room and space for a distance learning instructor. Staff was provided alternative spaces.

Staff and families were made aware of the mold issue through emails and school messenger on Wednesday. The district said there is no risk to people in the building.

The cause of the elevated mold levels is being investigated but generally is caused by high humidity — above 60% — or as the result of leaking water. No leaks were detected and there does not appear to be a link between the mold and a previous HVAC-related water leak that flooded the school in 2018, school officials said.

The news comes as one of two cohorts of students and all staff returned for the first day of classes. The district is for the time being using a hybrid model, splitting the returning school population into two groups who will have two days of in-classroom instruction per week and three days of distance learning. Some families have opted for full distance learning for their children.

It was a mix of excitement and anxiety for returning students and their families, many of whom were met Thursday morning by community members lined up outside the schools to greet them. The gatherings, smaller this year in light of the COVID-19 pandemic, have become a local tradition.

Smiles were evident even under the masks of some students.

“I’m excited to be back but nervous about my health,” said 11-year-old Amelie Kydd, a sixth grader at Bennie Dover Jackson Middle School Campus.

“I’m glad they’re doing the hybrid. I think it’s safer that way. I think my parents are nervous and excited, too,” she said.

Students, including many who walked to the middle school, were loudly reminded by wellness interventionist Tariko Satterfield that “your masks need to be over your mouth and nose.”

Satterfield delivered elbow bumps and words of encouragement to each of the students walking past him. “Welcome back. We’re going to have a good year,” he said.

New middle school Principal Chris Vamvakides said after six months away, it was good to finally have students back.

Across the city, Olga Vokolou ushered her two children into Harbor Elementary on Thursday. “I feel excited, scared, happy, overwhelmed and confused,” she said. “My children, as I’m sure all, want to go back to school.”

But Vokolou said she was torn, knowing the kids need the mental and social part of attending school and also worrying about the spread of COVID-19. “I am sure they did the very best to plan this,” she said, but added, “as parents, we are terrified and putting our faith in others. Every day will be a challenge.”

“We can’t show fear to our children but support them and help them go through this stage as easy and smoothly as possible,” she said.

Vokolou also wonders how just two days of school will impact the families who have to find day care, babysitters and other activities for their children on the three days they are not in school. Activities being offered by outside groups, such as the New London Recreation Department’s support program at Ocean Beach Park, further raise questions about exposure, she said.

g.smith@theday.com