Explosion at a Bio-Fuels Research Laboratory
The incident at a bio-fuels research laboratory occurred when a visiting research fellow was transferring hydrogen, oxygen and carbon dioxide into a low pressure gas cylinder to be used as a bacterial growth medium. The explosion was the result of a pressure gauge sparking, setting off the flammable gas mixture.
Event Date
March 16, 2016
Record Quality Indicator
Region / Country
Event Initiating System
Classification of the Physical Effects
Nature of the Consequences
Cause Comments
A digital pressure gauge was installed, not designed for the conditions in a portable tank, containing a mixture of gases to include: 70% Hydrogen (H2), 10% Carbon dioxide (CO2) and 20% Oxygen (the gauge was not explosion proof).More in general, the design of the experimental equipment was wrong.
Facility Information
Application Type
Application
Specific Application Supply Chain Stage
Components Involved
Portable gas cylinder
Storage/Process Medium
Storage/Process Quantity
0
Actual Pressure
1
Location Type
Location description
Inhabited Area
Operational Condition
Pre-event Summary
The tank that exploded was a portable 13 gallon ferrous cylinder. This particular tank was used to contain a mixture of gases to include: 70% Hydrogen (H2), 10% Carbon dioxide (CO2) and 20% Oxygen (O2) in that order and to a normal operating pressure of 50 psi. The tank was not grounded and was normally moved from stored location to areas where it could be filled. The tank would be moved approximately 3 feet to fill it with H2 and CO2, and then moved approximately 13' so it can be filled with O2.Tank, digital gauge, pressure relieve valve and fittings have been bought between November 2015 and January 2016. The tank was to have been rated at 10 bar or 150 psi. When the tank was assembled with its parts, a pressure test was done using the buildings air which produced 91.2 psi. Several leaks were detected, so the tank assembly was taken to the University maintenance for help in stopping the leaks. Tank, digital gauge, pressure relieve valve and fittings have been bought between November 2015 and January 2016. The tank was to have been rated at 10 bar or 145-150 psi. According to the Laboratory Professor the tank that failed was visiting research fellow's design; according to the visiting research fellow the design of the tank was that of the Laboratory Professor.In doing the research, the visiting research fellow needed to change the composition of the gasses to 70% H2, 25% O2 and 5% CO2. The premixed gas would then be connected to a reactor.On the day of the accident the researcher moved and filled the tank with a set amount of gasses using s a digital gauge that is battery operated. This gauge is a push bottom type for ON and OFF. When the researcher disconnected the hoses used to fill the tank, she checked the pressure in the tank to verify the amount to be 117 psi. She then pressed the OFF bottom and the tank exploded; prior to the explosion, she didn't hear any sounds of escaping or leaking gasses from any of the fitting or pressure relief valve.The researcher also added that earlier in the week of the accident, she was conducting another experiment using a smaller one gallon size air tank assembly nearly as identical to the one that failed using similar components to include a digital pressure gauge and premixed gasses. The tank pressure was set to 27 psi. After reading the gauge, she pressed the OFF bottom and a small internal explosion occurred: there was evidence of soot and smoke stains. Static shock also appeared to have been a problem as the researcher would get shocked on occasion when touching the tank.According to the researcher that was the first time the use of premixed gas in a portable tank to conduct the experiments was being done. In the past, each individual gas would have a separate hose line and be premixed at the reactor eliminating the use of a portable tank.
Currency
Lessons Learned
Lessons Learned
University of Hawaii workplace safety violations identified by HIOSHSource: Hawaii Occupational Safety & Health Division Citation and Notification of Penalty to the University of Hawaii, issued Sept. 16, 2016.1. The employer failed to provide a safe workplace by reducing employee exposure to potential explosion and fire hazards.2. The employer did not ensure that its safety practices were followed by employees and underscored through training, positive reinforcement, and a clearly defined and communicated disciplinary system.3. The employer did not ensure periodic in-house inspections were being performed in Hawaii Natural Energy Institute laboratories to determine new or previously missed hazards.4. Laboratory personnel working under the principal investigator did not use the required personal protective equipment at all times.5. Two exit routes were not available in the laboratory to permit prompt evacuation of employees and building occupants.6. The exit door did not swing out in the direction of exit travel.7. The employers emergency action plan(s) did not list the evacuation meeting point nor a way to account for the evacuees.8. The employer did not review the emergency action plan when employees were initially assigned.9. A fire prevention plan did not include specific provisions to address potential ignition sources in the presence of hydrogen and other flammable gases.10. Activities performed in the laboratory by researchers with the potential exposure to explosion and fire hazards were not assessed for appropriate personal protective equipment.11. Activities performed in the laboratory by researchers with the potential exposure to explosion and fire hazards were not assessed for appropriate glove protection to guard against static discharge and flame-retardant laboratory coats to guard against fire.12. Where hazardous chemicals were used in the workplace, the employer did not carry out the provisions of a written Chemical Hygiene Plan, which were capable of protecting employees from health hazards associated with hazardous chemicals in that laboratory.13. The employers Chemical Hygiene Plan did not include the standard operating procedures relevant to safety and health considerations to be followed when laboratory work involved the use of hazardous chemicals.14. The employers Chemical Hygiene Plan did not include criteria to determine and implement controls relevant to the gas mixing operation (engineering controls, personal protective equipment, administrative).15. The employer failed to review and evaluate the effectiveness of the Chemical Hygiene Plan at least annually and update it as necessary.
Event Nature
Emergency Action
Unknown
Detonation
No
Deflagration
No
High Pressure Explosion
No
High Voltage Explosion
No
Source Category
References
References
Chemistry World, May 2016, 17
Fire brigades post explosion report
381_2016-09-16-HIOSH-Citations-Penalties.pdf