2(a) A person shall not possess any firearm, electric weapon or device, destructive device, or other weapon as defined in s. 790.001(13), including a razor blade or box cutter, except as authorized in support of school-sanctioned activities, at a school-sponsored event or on the property of any school, school bus, or school bus stop.
(13) “Weapon” means any dirk, knife, metallic knuckles, slungshot, billie, tear gas gun, chemical weapon or device, or other deadly weapon except a firearm or a common pocketknife, plastic knife, or blunt-bladed table knife.
(3) (b) “Tear gas gun” or “chemical weapon or device” means any weapon of such nature, except a device known as a “self-defense chemical spray.” “Self-defense chemical spray” means a device carried solely for purposes of lawful self-defense that is compact in size, designed to be carried on or about the person, and contains not more than two ounces of chemical.
So as long as it contains less than 2 oz of chemical it is legal but if it contains more than that it is a "weapon" and is prohibited on school property.
That is where things begin to get a bit muddy. First, look at 790.115(1), which prohibits the DISPLAY of a weapon in a rude, careless, angry, or threatening manner (not in lawful self defense) at a school-sponsored event or on the grounds or facilities of any school, school bus, or school bus stop, or within 1,000 feet of the real property that comprises a public or private elementary school, middle school, or secondary school, during school hours or during the time of a sanctioned school activity. This is important, because it separates school facility and school grounds, proving that the law considers them to be two different things.
Then you look at paragraph (2), which says:
(12)(a) A license issued under this section does not authorize any person to openly carry a handgun or carry a concealed weapon or firearm into: (irrelevant parts omitted)
This seems to indicate that a person with a concealed weapons permit may lawfully possess a concealed weapon on school property, as long as it is not at a school sponsored athletic event, in a school facility or building, and, if a firearm, it is kept in a vehicle. A person may also store weapons in a vehicle in a school parking lot if the school district permits it, but no district in Florida has done so. Additionally, since (our school) is used as a community learning center after hours, it is not legally a school for the purposes of this law after hours, unless there is a school sponsored event going on (like a football game).
Even more confusing, a swim meet at the community pool would constitute a school sponsored sporting event, meaning that anyone at the community center would also be prohibited from having a weapon, even if they were not affiliated with the sporting event or school.
As usual, I am not a lawyer, this is just my opinion, etc.