On Sunday I spent several hours running around in the woods, off-trail, through brush, etc. (paintball),  and my feet and lower legs are now covered in about two dozen fire ant bites.

Is there any sort of chemicals I can spray on my boots/pants to repel these little fuckers next time?

Somehow a couple made it inside my boot and stung between my toes. That sucks.

Fire extinguisher?

Here's a thing from Texas A&M about fire ant control, but I think it's more to do with ants around the home

http://fireant.tamu.edu/controlmethods/

Here's a site with a chemical you might be able to put on your boots.

Permethrin should help, available at Wally World in SG dept

That worked, so far.

Sprayed my boots and pant legs. No new bites yet, though I also stayed out of areas where I thought there were lots of fire aints.

Permethrin works really well for pre treating clothes, boots, fabrics, lawns, houses.... Picardin works on bare skin if they get past the stuff pre-treated.

These are both exactly what I use as well.  I do find it ironic that I can mow the lawn (I have about three acres and mow with the push mower for exercise and to get a tan) in sandals where there are numerous fireant mounts and I disturb them all.  I never (or very rarely) get bit...you move quickly and don't stand in one place too long.  However, when I put on pants and heavier shoes for weed-whacking, I get a half dozen or so bites and I don't even recall where the mound was.  Bottom line, make sure you stay aware of your surroundings and don't stay in one place for too long...keep moving  Treat your shoes, socks and pants with Permethrin; one treatment will last all summer.  Double up with Picardin on the skin.  Now, if you could just make some airsoft grenades out of pieces of a fireant mounds you would have a very effective weapons to chase the enemy out of cover

ROCK6

Yeah, most bites come from disturbing a mound, and when you do that the repellents are useless.  They basically have just declared war on you.   Avoidance is the only decent preventative.  Been living with those little suckers for years and I absolutely DESPISE them.

Doc