My question involves employment and labor law for the state of: South Dakota

So I work for a combination fire dept. that has 5 employees and a paid cheif (6 employed). We work off the 7(k), so we work 24hr on 48off and based of a 56 hr work week. In the summer we have to go out on wild fires as part of our duty. while on fire we usually work 16 hour days for 14 consecutive days. in order to get overtime we would have to work over 212 hours in a 28 day period.

So... the cheif says that he is exempt from paying over time since the dept is so small... flsa says(less than 5 is exempt)?
cheif says that the 212 hours have to be in consecutive days so If I get one day off in 28 days the hours start over ? is this true.
last 28 days i worked 344 hours!

we are on salary and the dept gets all the extra money when there is out of state money to be had. never gotten an over time check