perform hydrotesting on several fire extinguishers that were due for their periodic inspection. During the testing process, one of the extinguishers failed to hold pressure, indicating a possible internal defect or corrosion in the cylinder. I immediately removed it from service for safety reasons and tagged it for disposal, as per NFPA guidelines. I then continued testing the remaining units, all of which passed with no issues. To maintain coverage for the client, I replaced the failed extinguisher with a certified, freshly tested unit from our inventory. All results were documented, and the client was updated on the status and actions taken.