A month after the Philadelphia Department of Parks and Recreation announced it would keep using Mosquitos indefinitely, Councilmember Helen Gym said she would hold hearings to determine whether they’re harmful to young people.

In Philly, 33 public spaces have installed the sonic devices, which act as a deterrent by broadcasting a high-pitched ringing noise overnight.

During Thursday’s City Council session, Gym authorized the Committee on Children and Youth to hold hearings on the sonic devices. Parks & Rec says they’re intended to prevent vandalism and loitering. The noise they emit is played at such a high frequency that it’s only supposed to be audible by young people aged 13 to 25.

Gym has been skeptical of the Mosquitos since Billy Penn first reported on their use in local parks and rec centers.

“I want to ensure that no new devices are being installed,” Gym said in January, “until we’re able to determine the effects of the current devices on the communities where they are already installed.”

The hearings haven’t yet been scheduled, but Gym hopes they’ll happen before the end of March, according to her spokesperson Greg Windle.

“As Philadelphia considers the use of these devices, it is important to fully consider and weigh their impact as well as manage any issues or concerns in a non-discriminatory way,” reads the resolution, which was cosponsored by Councilmembers Kendra Brooks, Jamie Gauthier, Katherine Gilmore Richardson and Isaiah Thomas.

The goal of the convenings, per the resolution, is to figure out whether kids who are exposed to the devices might experience health problems, like “dizziness, headache, nausea and impairment.”

The resolution notes that a handful of cities around the world that have already banned the Mosquito device on those grounds — including Washington D.C. and the Vancouver public school system.

From July 2019 to January 2020, following Billy Penn’s report, Parks & Rec conducted an internal review of the devices. City officials said the review process uncovered widespread support for the Mosquito, so they decided that the sonic machines would remain in place.

“The majority of our on-site staff are supportive of them,” said Parks & Rec’s deputy commissioner Aparna Palantino. “I don’t have a definitive response from anyone that said they didn’t want them.”

In the hearings, Gym hopes to hear from psychologists, her spokesperson said, and ideally a public policy expert who has experience studying the Mosquito devices in another city.

Gym’s resolution also emphasized that young people will be included in the hearings. Palantino told Billy Penn last month that teens weren’t included in Parks & Rec’s internal review process.

“Providing safe and welcoming places where young people can learn and grow is central to our mission at Philadelphia Parks & Recreation,” said the department’s spokesperson Maita Soukup. “We look forward to engaging with Council on these important issues.”

The city’s been installing the devices since at least 2014, mostly upon request from district councilmembers or rec center staffers. Some legislators are still very much in favor of their use.

“I want them in all my rec centers,” District 6 Councilmember Bobby Henon said last month. “My constituents have had issues with kids hanging out after curfew, and it’s caused an issue in the neighborhoods when it comes to public safety.”