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Lab Safety

Spark from pressure gauge caused University of Hawaii explosion, fire department says

Postdoc Thea Ekins-Coward, who lost an arm in the incident, was using a gauge not specified for work with flammable gases

by Jyllian Kemsley
April 19, 2016

UPDATE: A subsequent investigation by the University of California Center for Laboratory Safety determined that the cause of the explosion was an electrostatic spark, after laboratory testing ruled out a spark from the pressure gauge. Read the full story here.

An explosion last month that caused a University of Hawaii, Manoa, postdoctoral researcher to lose an arm was caused by a spark from a digital pressure gauge that was not designed for use with flammable gases, says a Honolulu Fire Department investigation report.

Photo showing a lab bench littered with debris.
Credit: Honolulu Fire Department
Debris littered a lab bench after the explosion.

Thea Ekins-Coward was combining hydrogen, carbon dioxide, and oxygen gases from high-pressure cylinders into a lower pressure tank when the incident occurred. She has not given the university permission to release information about her condition, said spokesman Daniel Meisenzahl at an April 18 press conference.

The gas mixture was “food” for bacteria being used to produce biofuels and bioplastics. Ekins-Coward was working for the Hawaii Natural Energy Institute under researcher Jian Yu. A 2013 paper by Yu indicates a set-up in which gases are plumbed through a mixing device called a gas proportioner directly into the bioreactor (Int. J. Hydrogen Energy 2013, DOI: 10.1016/j.ijhydene.2013.04.153). The gas gauge identified in the paper is an “intrinsically safe” model designed to prevent ignition.

But after Ekins-Coward started in the lab last fall, she purchased a 49-L steel gas tank, a different gauge not rated as intrinsically safe, a pressure-relief valve, and fittings, and she put them together, Yu and Ekins-Coward told fire department investigators, according to the report. Ekins-Coward would add the gases to the portable tank, which would then be connected to the bioreactor. She was using a mixture of 70% hydrogen, 25% oxygen, and 5% carbon dioxide for her experiments, the report says.

In the week before the incident, a similar set-up with a 3.8-L tank resulted in a “small internal explosion” when Ekins-Coward pressed the off button on the gauge, the fire department report says. She also occasionally experienced static shocks when touching the tank, which was not grounded. She reported the shocks and possibly the small explosion to Yu, who told her not to worry about it, the report says.

On the day of the incident, the 49-L tank exploded when Ekins-Coward pressed the off button on the gauge. “She did not lose consciousness or hit her head; she was aware that she lost her arm in the explosion,” the report says. “She couldn’t open the door to the lab, the door was stuck closed.” Security officers and a graduate student kicked in the door to help Ekins-Coward get out. Her right arm was severed just above the elbow, the report says.

The University of Hawaii hired the University of California Center for Laboratory Safety to independently investigate the incident. That report is expected to be completed by the end of this month. The Hawaii Occupational Safety & Health Division is also investigating the incident.


Disaster Scene

These photos, released by the Honolulu Fire Department, 
llustrate the force of the March 16 explosion and its consequences.
(warning: some images are graphic)

[+]Enlarge
Credit: Jian Yu/U Hawaii
The steel tank that ruptured in the March 16 explosion.
Photo of an air tank
Credit: Jian Yu/U Hawaii
The steel tank that ruptured in the March 16 explosion.
[+]Enlarge
Credit: Honolulu Fire Department
The explosion caused damage in the hallway outside of the lab.
Photo of a damaged wall with exposed insulation.
Credit: Honolulu Fire Department
The explosion caused damage in the hallway outside of the lab.
Photo of the hallway outside the lab door, showing bloody footprints and gloves, a fire extinguisher, a wrench, and a lab notebook on the floor.
Credit: Honolulu Fire Department
The hallway outside the lab door after the explosion.
Photo of eight compressed gas cylinders.
Credit: Honolulu Fire Department
Compressed gases in the lab included hydrogen, carbon dioxide, helium, and carbon monoxide.
Photo of lab door showing cracked glass.
Credit: Honolulu Fire Department
This steel tank ruptured during the explosion, which severed a researcher’s arm.
Photo showing cabinets of chemicals and glassware plus a steel reactor.
Credit: Honolulu Fire Department
Chemical bottles fell and glass broke in the northeast corner of the lab, next to the bioreactor for growing bacteria.
[+]Enlarge
Credit: Honolulu Fire Department
The explosion knocked down ceiling panels, broke light fixtures, and scattered debris throughout the lab.
Photo showing general damage to the north side of the lab.
Credit: Honolulu Fire Department
The explosion knocked down ceiling panels, broke light fixtures, and scattered debris throughout the lab.
[+]Enlarge
Credit: Honolulu Fire Department
The remains of the steel tank sit at the site of the explosion, near the south wall of the lab.
Photo showing general damage to the south side of the lab.
Credit: Honolulu Fire Department
The remains of the steel tank sit at the site of the explosion, near the south wall of the lab.
Photo showing shattered fume hood pane and lab counter with debris.
Credit: Honolulu Fire Department
The explosion also shattered fume hood sash windows and knocked over equipment in the northwest corner of the lab.
Photo of two compressed gas cylinders, one oxygen and one unidentified.
Credit: Honolulu Fire Department
An oxygen cylinder was nearly knocked over in the southwest corner of the lab, something that could have added to the damage.
Photo of a circuit board on top of debris.
Credit: Honolulu Fire Department
Possible circuit board from the pressure gauge that caused the explosion.
Photo of a circuit board.
Credit: Honolulu Fire Department
Photo of a circuit board on top of debris.
Photo of a bloodied lab coat resting on a chair.
Credit: Honolulu Fire Department
Postdoctoral researcher Thea Ekins-Coward lost an arm in the explosion.

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