Usually not
Short answer: Not if it's charged. A fully discharged and depressurized extinguisher can usually be recycled as scrap metal.
San Mateo Consolidated Fire Department says extinguishers that aren't completely empty are hazardous and should never go in the trash because the pressurized contents could explode. Once fully discharged with the head removed, the cylinder can go to steel recycling.
Have it recharged, take it to HHW if it still has contents, or fully discharge it and recycle the empty cylinder as ferrous metal.
Checked October 2026. Rules change; your hauler's prohibited-items list is the final word.