Disposal of expired fire extinguishers

Hi, folks, I was looking for the proper way to dispose of an old fire extinguisher. It's not used (thankfully), but it's time to replace it. I looked up the Houston Fire Department website, and it referred to the Houston Solid Waste department. When I looked there, there was no mention of fire extinguishers except that they weren't accepted at the Westpark Recycling Center. Any ideas? Do folks just put it in regular trash? Seems kind of dangerous.