Florida officials are warning residents that toxic red tide algae could be making its way toward several of the state’s beaches.

Hundreds of fish were found washed ashore at Fort Lauderdale Beach in Broward County, prompting officials to test for red tide. Several beachgoers in the area also reported coughing and mild irritation due to possible red tide exposure. On Friday morning, Mayor Dean Trantalis said beaches will remain open until test results from the Florida Fish and Wildlife Commission can confirm the presence of toxic algae, Local 10 reported.

Despite the beaches being open to the public, signs are being placed on several to warn visitors of potential health risks of red tide, which can include burning eyes and throat and lung irritation.

“For our asthma patients or patients with chronic lung disease like emphysema and bronchitis, it’s a little bit worrisome, and they could have several days of problems if they’re not careful,” Glenn Singer, a pulmonologist at Broward Health Medical Center, told NBC Miami.

Beaches in Miami-Dade reopened Friday after a brief closure Thursday when tests reported the presence of red tide.

“Swimming is safe for most people,” Mayor Carlos Gimenez said in the statement. “In fact, beaches on the west coast of Florida, which have been plagued by red tide in recent months, remain open.”

Following a week of closures, beaches in Palm Beach and Marin County also reopened Friday.

The Florida Fish and Wildlife Commission created an interactive map showing the presence of red tide in Florida that will be updated daily so that beachgoers can stay informed of the risks. This red tide occurs when “colonies of algae — simple plants that live in the sea and freshwater — grow out of control while producing toxic or harmful effects on people, fish, shellfish, marine mammals, and birds,” according to the National Ocean Service.

Florida Gov. Rick Scott announced Thursday that the state would spend $3 million to fight red tide’s appearance in South Florida, according to the Sun Sentinel.

“So far, the state has provided more than $16 million to help minimize the impacts of harmful algal blooms and expand our research and understanding of red tide, including funding to help scientists test innovative solutions for this phenomenon,” he said.