The Florida Highway Patrol said at least seven separate crashes were part of the Friday afternoon pileup, which blocked the southbound lanes of the highway for 6 hours, the Bradenton (Fla.) Herald reported.
At least two people were transported to hospitals by helicopter, but their injuries were not considered life-threatening, FHP said.
Thirteen victims were admitted to Lakewood Ranch Medical Center with broken bones, friction burns from airbags and lacerations from broken glass, hospital spokeswoman Jennifer Bryan said.
One of the vehicles involved was a tanker that leaked liquid calcium, which is not considered hazardous, the Sarasota County Sheriff's Office said.
Eighteen units from the Sarasota County Fire Department responded to the scene.
A light rain was falling at the time of the first collision near the Sarasota-Manatee county line. A slight hill in the area prevented motorists from seeing the crash in time to stop, officials said.