A group of parents of children with special needs sued the Central Bucks School District late Friday, alleging the district’s plan to start the school year Monday without masks or other COVID-19 mitigation measures violates their rights under the Americans with Disabilities Act.

The lawsuit — backed by a fund-raiser started by parents that had amassed more than $35,000 as of Saturday afternoon — follows a 5-4 vote by the school board Wednesday night rejecting a mask mandate and other measures ahead of the new school year.

It asks U.S. District Court in Philadelphia to order the school district to follow Centers for Disease Control and Prevention guidelines for mitigating the virus in schools.

“Together we have made a phenomenal statement that we need to follow CDC and [American Academy of Pediatrics] guidelines to keep the children, teachers and staff in our schools safe as well as prevent the spread of COVID in our community,” Susan Lipson, a family medicine physician who helped organize the GoFundMe, wrote on its page.

The district and the school board president did not immediately respond to requests for comment Saturday.

The challenge comes as Gov. Tom Wolf’s administration has raised alarm about pandemic mitigation measures in schools — and has targeted Bucks County, with the state’s acting health secretary warning county commissioners earlier this week that their Health Department’s school guidance could hinder its response to outbreaks and jeopardize in-person schooling.

» READ MORE: Pa.’s health secretary rebuked Bucks County officials over their school reopening guidance, prompting them to revise it

The county revised its guidance, but a number of Bucks school boards haven’t followed suit — Central Bucks among them. The board’s rejection Wednesday of a plan aligned with the county’s new guidance leaves in place an earlier proposal passed in July that doesn’t require masking or notification to parents of positive cases within their child’s classroom.

Parents suing the district — whom the lawsuit identifies only by their initials because “universal masking is a very contentious issue in the district” — say the plan puts their children “at risk of death and debilitating illness from COVID-19.”

Some of their children are immunocompromised or have illnesses that put them at heightened risk of severe side effects from the virus, according to the lawsuit, while others need in-person instruction because of their disabilities.

“This is about advocating for children with disabilities in the school district, who at times really haven’t had a voice” in the debate around school reopening plans, said Katie Metcalfe, a lawyer for the parents.

Whether to require masks in schools has been a bitter controversy in communities across the region. In Central Bucks, where parents opposed to masking argued before Wednesday’s vote that children face little risk from the virus, some board members voiced opposition to the administration’s proposed mask requirement because it wasn’t tied to community transmission rates or other metrics.

» READ MORE: Central Bucks School Board votes down mask requirement

The plan will be on the agenda when the board meets again Tuesday night, two days into the new school year.

Wolf this week asked the Republican-led legislature to impose a school mask mandate — a request that lawmakers rejected. The governor’s office said that as of late July, just 59 out of 474 districts that had submitted state-required health and safety plans were mandating masking.

A spokesperson for the governor declined to comment Friday on whether Wolf planned further action.

“We agree that decisions are best left to local leaders, but we are increasingly concerned that Republican members are interfering with these decisions and threatening school boards either implicitly or explicitly,” said spokesperson Rachel Kostelac.

Before this week, Bucks County had already revised its guidance to call for universal masking, citing concerns from area hospitals. But it had continued to recommend mitigation measures that didn’t align with CDC advice — suggesting that children with COVID-19 could return to classrooms after being fever-free for 24 hours, for instance. It also said it wouldn’t perform contact tracing in schools.

That changed after acting Health Secretary Alison Beam sent a letter to county commissioners Monday, calling the guidance “alarming” and unsupported by scientific evidence. But while the county tightened its recommended safety measures, a number of school boards haven’t followed suit.

Bensalem also voted 5-4 against a mask mandate this week, while Council Rock agreed to notify families of students exposed to COVID-19 in classrooms but didn’t impose a mask requirement. Some area school boards outside the county have also endorsed mask-optional plans.

The case is likely to be closely watched: Parents in other communities in favor of masking have been organizing in opposition to school boards that have voted against requirements. Others opposed to masking have also threatened legal challenges.

Metcalfe and fellow lawyer Adrianna Cherkas say they have been contacted by additional Central Bucks parents looking to join the lawsuit.

Parents are making decisions about sending their children in for the first day of school if a judge doesn’t act by Monday, they said.

One of the parents in the lawsuit — who requested anonymity due to fear of threats — said she had made accommodations with a school nurse to notify her if there were COVID-19 cases in her child’s classroom.

She worries that discussion around the low risks to children — and arguments that healthy children shouldn’t have to wear masks — overlooks children like hers with serious medical conditions.

“I’m glad that people have healthy children,” she said. “That’s fantastic. But there’s a bigger picture here, and it’s being ignored.”