Fire Extinguishers Hazardous Waste Never Throw in the Garbage Even if you are certain there is no remaining pressure, never throw a fire extinguisher in the garbage. It could explode in a hot garbage truck. Check Regularly Check your fire extinguisher every month to make sure that it is safe to use. The needle should point to the green area of the pressure gauge. If the needle points to the red area, you must replace your extinguisher or have it refilled. Most fire extinguishers only last 5 to 10 years, even if they have never been used. Release Pressure for Proper Disposal First, check your fire extinguisher’s pressure gauge. If there is still pressure, shoot a small amount of the contents into an open area. Let the canister sit for a few days to release the excess pressure before disposing as hazardous waste. Ways to Reduce Never Test If you spray your fire extinguisher even once, you must replace it or have it refilled.