ST. PETERSBURG, Fla. (AP) — The National Weather Service says people may experience respiratory problems because of a persistent bloom of toxic red tide off Florida’s Gulf coast.

The service issued a “beach hazards statement” affecting the oceanfront shores in Pinellas County from 11:30 a.m. Friday through at least 10 p.m. Saturday. People with asthma, emphysema or any chronic lung disease may be more sensitive.

Many experts suspect the fish-killing red tide outbreak in the Tampa Bay area has been exacerbated by the release earlier this year of more than 200 million gallons of contaminated water from an old phosphate operation in Manatee County.