Truck driver delivering to a water treatment / sewage plant

I'm a local truck driver in the state of Florida only. I always carry on the road. I have yet to find a law that pertains to local drivers. I know you cant carry in your commercial vehicle if you cross state lines. I don't. I have had FDOT pull me for a routine check and first off i gave him my permit. He asked if I had a weapon on my person a told him i did and he simply asked me to put it in the glove box until we were done. Does any one know if it's legal or not to carry in my big rig? Next question. I deliver and pick up at city water and sewer plants. I keep my weapon in the truck when I exit the truck while on their property. I do believe that they are State and government run. Is this illegal? Another driver for the same company was approached by the boss and asked if he was carrying while making his routes to these plants. he said yes. The boss said leave it at home, that the company could loose their contracts if he we're caught. We can carry to our work place now, Isn't the inside of our trucks our work place? sure seems like it. lol. Thanks for the replies in advance.