Naled has been in use in the U.S. since the 1950s

Public concern over the use of Naled, a chemical that’s being deployed in airborne anti-Zika efforts, is rising in the South, particularly around Miami, Florida. A public protest outside of South Beach’s City Hall Wednesday prompted Miami-Dade officials to delay the start of aerial spraying, but only for 24 hours.

Naled is banned in the European Union, and its use in Puerto Rico – one of the areas hit hardest by the Zika virus – was protested by officials who derided it as dangerous for pregnant women.

Get push notifications with news, features and more.

“Naled… can essentially kill anything,” Tanjim Hossain, a graduate research fellow at the University of Miami, told CBS News. “When a droplet of the insecticide touches a mosquito, it kills the mosquito pretty much instantaneously.”

The Centers for Disease Control and Prevention (CDC) and the Environmental Protection Agency (EPA) have both sanctioned Naled for use. It’s been in use for mosquito control since 1959 in the U.S. and has an extensive history of use: In 2004, eight million acres across Florida were treated with it as part of the emergency responses to hurricanes; and in 2005, after Hurricane Katrina, five million acres of Louisiana, Mississippi, and Texas were treated with Naled to kill mosquitoes. Its use isn’t restricted to rural areas, either: In 1987, the CDC treated 177,000 acres of metropolitan San Juan in Puerto Rico as part of Dengue fever control efforts.

“Decisions on when and where to conduct aerial spraying are made by local mosquito control districts and local government, in consultation with state and federal agencies, like the Centers for Disease Control and Prevention, when appropriate,” a spokeswoman for the Florida Department of Health told PEOPLE.

“We are more afraid of this than we are of Zika,” Liza Samuel, South Beach resident and mother of three, told the Miami-Herald.

“I don’t particularly want to do this,” Miami-Dade Mayor Carlos Gimenez, told a crowd Wednesday, according to the Herald. “We tried everything to not to get to this point.”