JinnKai,
You might want to check that information again. Or let me know where you looked, because I tried to google it real quick but not much came up. Maybe it depends on where someone lives, like in rural Oregon the firefighters are volunteer or either private or county workers. I actually don't know, but you have to pay for their services each year, they aren't paid with the taxes that pay for regular city and county services.
But in Southern california, firemen have always been seen as law enforcement by a lot of different people. They have the power to search and seize and they write tickets, they arrested my friend when they put a fire out in his house and found weed.
Most importantly though, they are big mofos in shape! and they have the ability to knock heads
which is what would be necessary if a big dude was trying to break into a lady's house...all the firemen I know wouldn't really worry about authority to arrest at that point.