The Halon extinguishers started to fade out in 1994, same route as R12 freon.
I still see Halon engine fire bottles though, the Halon is recycled during Hydrostatic testing of the Bottle. It is getting more and more expensive for older aircraft. Exchange bottles run $2500 and up for new aircraft , an old Lear Jet 45 bottle runs $30k IF you can find one. <--these type get damaged when the Squib fires and blows the disc into the bottle.
I did a study for a Six Sigma project I ran a few years ago to remove all the Drychem extinguishers from all 10 Factory owned Service Centers. Result of of someone discharging a drychem extinguisher in the tailcone of a Biz Jet. The dry chem turns to a liquid acid above 386F. Eats the hell out of Aluminum and ruins electronic and electrical systems.
Halotron I is quite good and does have a longer spray 6-45ft. Not a CFC issue like Halon.
This fact sheet sheds more info on the properties.
https://www.h3raviation.com/pages/faq#3
6. Does Halon remove oxygen from the air?
It is a common misconception that Halon "removes oxygen from the air."
According to the Halon Alternative Research Corporation (
www.harc.org): "Three things must come together at the same time to start a fire. The first ingredient is fuel (anything that can burn), the second is oxygen and the last is an ignition source. Traditionally, to stop a fire you need to remove one side of the triangle-the ignition, the fuel or the oxygen. Halon adds a fourth dimension to fire fighting-breaking the chain reaction. It stops the fuel, the ignition and the oxygen from working together by chemically reacting with them
https://www.elitefire.co.uk/help-adv...extinguishers/
https://www.halotron.com/images_video.php