I believe that this Lessons Learned can apply to a lot of laboratory equipment and chemicals in research settings.
- Ralph
Lessons Learned 2023-UTB-ORNL-0024
Lessons Learned Resulting from 30kV DC Shock Contact with Energized Fluid
Topics: Electrical
Originator: GeraldBarth
OE Document Number: 16565
Statement: When conditions in the planned scope of work changes (such as with troubleshooting) that results in a change in hazard exposure.
Event Overview: On May 26, 2023, UT-Battelle (UT-B) research staff member was performing electrospinning activities when they observed then came into contact with energized fluid leaking from the syringe end in the dosing dispenser on sputtering equipment. Electrospinning involves electrostatic deposition of thin layers of metal by using highly charged ions to eject particles in solution from a target to a surface. The process uses metal particles in a solution that is passed through an orifice charged to 30kV DC positive (anode) and the material to be deposited on is negatively charged (cathode). The dispensing syringe was mounted in dispenser external to the sputtering enclosure around the anode and cathode.
Research staff member observed fluid leaking from syringe at adapter to tubing and attempted to check and tighten connection removing syringe from dispensing unit. Staff member determined the nozzle inside enclosure may be plugged and cause of issue. While holding syringe in right hand they reached over to turn off the electrospinning power supply on enclosure. When they touched the enclosure switch, the research staff member came into contact with grounded enclosure and felt shock from left shoulder to hand.
Unit was turned off, Division Electrical Safety Officer (DESO) was contacted and research staff member was sent to medical services for evaluation. Electrician and ORNL Hazardous Energy Control SME evaluated setup and building power for grounding, unit is powered from 120V GFCI outlet that had not tripped, and unit ground and power ground was verified. No grounding issues were discovered, and cause was determined to be staff member holding energized syringe in one hand and contacting grounded enclosure with other. Electrospinning unit was at maximum setting of 30kV DC and unit specification lists max current of 0.133mA (0.000133A). Researcher was wearing nitrile gloves and safety glasses with side shields.
It is suspected that the cause of the electrical shock was likely due to the researcher’s right gloved hand being saturated with a conductive solution. When the researcher reached for the voltage knob with his left gloved hand to turn down the voltage, he contacted or came close enough to the metal on the spin box cover for charge to jump to ground. This caused a discharge of the conductive chemical mixture to move through the researcher to the metal spin box cover.
Electro spinner manual includes the following note:
Do not touch connections unless the unit is OFF and the capacitance of both the load and the power supply is discharged. Allow at least 30 seconds after switching off the unit to discharge the capacitance of the high voltage power supply. Then, discharge the remaining stored energy by connecting the high voltage output to
ground.
Analysis:
• Change in condition resulted in work performed outside the normal work and shift to troubleshooting and corrective actions did not assess changing conditions and hazards.
Lessons Learned:
• No matter the task, understanding work control responsibilities, delegation of authority, proper planning, and effective communication are requirements for safe operations.
• Work activities should be performed within the defined scope of work. A change in conditions that results in a new or expanded scope of work must be evaluated for new/additional hazards.
Recommended Action:
Guarding with signage to be used in front of syringe dispensing unit and tubing to spin box warning to turn off spin box power and ground the system to dissipate any remaining charge before accessing syringe/tubing.
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