The minimum training requirements vary from state to state, and even fire department to fire department. Some will hire you with nothing but a high school diploma, and then teach you everything you need to know!
Most often however, firefighters are required to be certified as a "Firefighter I" and "Emergency Medical Technician - Basic." These certifications can typically be obtained at your local community college. Each one takes one semester usually, so about one school year total. Most fire departments don't require any more college than that, but an Associates or Bachelors degree will help get hired, and help you get promoted later on.
While a community college and those two entry level certificates are usually enough to get you hired, know that firefighting takes a lot of training and education even after being hired. Once you're a firefighter you may go to specialized schools to learn how to cut people out of wrecked cars, rescue people underwater in SCUBA gear, hang from ropes off of cliffs or skyscrapers, put out airplane/jet fuel fires, etc. etc.
I hope that helped. Let me know if you have any more questions!
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