Any Unknown or Unlisted Aircraft Manufacturer
Maintenance Airframe; Maintenance Powerplant
Human-Machine Interface
Deviation / Discrepancy - Procedural Hazardous Material Violation; Deviation / Discrepancy - Procedural Maintenance; Deviation / Discrepancy - Procedural Published Material / Policy
General None Reported / Taken
Human Factors
I was made aware that on date on Aircraft X that 3 hazmat parts (batteries) were left in the galley area on the plane. I was assigned to the interior area on an A2 check. WhiIe was accomplishing job card; step 1 is 'operational check of the electronic circuit of inflatable restraint'. This check failed at all seats on card (row 5lh; 5rh and seat 10f). I ordered said batteries for 3 rows. My lead ordered 7 inflatable airbag seat belts/harnesses. I never used any of these parts but they were scattered around near where I was working. I reseated electrical connections at seats and they all passed the test. Step on job card was done. There were other mechanics also assigned to the interior. They started cleaning up the parts that were ordered. I did a walkthrough of the cabin when I was done and didn't see any parts anywhere. I assumed all parts were off the airplane and returned to stores.I had assumed that the other mechanics had returned parts to storesCommunication with other mechanics.
Airline Mechanic reported being notified Hazmat parts he was working were left on board after he departed.