Hillsborough is the seventh-largest school district in the U.S., with more than 213,000 students. As of Wednesday, 10,384 students and 338 staffers are isolated or under quarantine, the district told ABC News.
In total, there were 1,805 COVID-19 cases among students and staff, according to the Tampa-area district's COVID-19 dashboard.
The district is requiring masks for students, but parents can opt their children out. To date, at least 28,000 parents have opted out, district officials told ABC News.
The district held an emergency school board meeting Wednesday to discuss how to respond to the crisis.
MORE: How masks impact the spread of the COVID-19 Delta variant in a classroom
In the heated gathering people shared points both for and against a mask mandate.
One mother of a student yelled, "Have any children died?" as a result of the virus. Some people in the audience shouted back that children have. Parents against masks argued that face coverings prevent kids from smiling at each other and communicate with their peers and teachers.
A wife of a teacher said during the meeting that her husband is immunosuppressed and suggested the district enforce masks just as they enforce girls adhere to a dress code that bans spaghetti straps. One high school student told the anti-maskers, "This tiny piece of cloth is not taking away your freedom. ... Grow up."
After a marathon meeting that ran nearly three hours longer than intended, Hillsborough County voted to institute a mask mandate for at least 30 days, but parents will be able to opt their kids out with a note from a medical provider.
District officials said they're providing personal protective equipment and sanitation stations for each classroom, and have installed MERV-13 air filters at each school.
"As we work to create the safest environment for our students and staff, we also must abide by the governor's executive order, as well as emergency rules from the Department of Health and state Board of Education. This requires our district to preserve a parent's right to choose to wear a face covering in school," a spokesperson for the district told ABC News. "The Governor has been clear that if school districts do not abide by this order, they could face financial consequences."
Last month, Gov. Ron DeSantis issued an emergency order giving parents the final say over masks for kids in school. At a press conference last month, he said Florida students shouldn't be "muzzled," adding, "We need them to be able to breathe."
Elizabeth Devolder pulled her two children, who are in fifth and second grade, out of school to voluntarily quarantine them due to the "terrifying" rising number of virus cases.
"Although they were not immediately exposed, and they're not required to quarantine, I felt like why do we have to wait for our kids to get sick before we take action?" she told Tampa ABC affiliate WFTS.
The district is offering face-to-face instruction as well as virtual classes for the 2021-22 academic year.
The Bay Area of Florida has seen an uptick in virus cases. In Pinellas County, 521 cases among students and staff have been reported this school year, while in Sarasota there have bee 227 reported and in Manatee that figure stands at 480, according to those districts' respective dashboards.
In a similar meeting to the one in Hillsborough County, Miami-Dade County's school board voted Wednesday to also mandate masks with the ability to opt out with a medical note.
Mounting COVID-19 cases in schools are a rising concern as communities head back to in-person learning, especially as children under the age of 12 are not yet eligible for vaccines.
Florida currently has the country's highest COVID-19 case rate. The state reported 151,415 new cases from Aug. 6 to Aug. 12 and 286 deaths, with a new-case positivity rate of 19.3%, according to its latest weekly COVID-19 report. And cases among children are up, with over 31,700 new cases reported last week among those 19 years old or younger.
ABC News' Whitney Lloyd contributed to this report.