An Analysis of Three Lab Accidents: Could having a PHA/JHA make the difference?
By Paul Cotter and Renee Witherspoon
Some say that a Process Hazard Analysis (PHA) or a Job Hazard Analysis (JHA) takes too much time and is not worth the effort. From our perspective as health and safety professionals, it is absolutely worth the time and effort! Building materials and equipment can be replaced, but is it worth risking the possibility of an injury or death?
A review of three laboratory accident investigations shows that if the researchers had implemented a PHA or JHA, and incorporated it into their standard operating procedures (SOP), they could have identified the hazards and critical steps, and might have prevented the catastrophic failure that resulted in serious injury, loss of valuable research time and millions of dollars in damage.
What is a PHA/JHA?
A PHA or JHA can be one of the best tools to determine and establish proper work procedures and to identify potential hazards in an operation, such as a laboratory setting. Both are systematic processes primarily used by industry to determine where safety improvements can be made to reduce the consequences of an unplanned event, such as a release of hazardous chemicals or an explosion. The result of a PHA or JHA will not only be the development of safer, more effective work procedures, but it is an excellent resource for training employees to do their jobs safely.
Where a JHA covers a specific task, a PHA is a more in-depth analysis of potential causes of fires or catastrophic events for equipment, pressure relief devices, chemical storage, emergency systems and the human factor, which includes training of personnel. For PHAs or JHAs to be effective tools, management of the organization must be supportive and follow through with any corrective actions identified during the process.
The University of California at Irvine
In 2001 at the University of California at Irvine, there was a chemical-related accident that resulted in serious injury to a doctoral student and approximately $3.5 million in damage to the facility. A walk-in hood contained a distillation unit used to recover and purify benzene. At the time of the accident, the distillation process had been underway and was apparently working properly. A student noted part of the unit had become detached, and the head of the reflux/distillation was “bouncing up and down” as benzene vapor was being released.
When the student entered the walk-in hood and attempted to manually secure the reflux/distillation head on the unit, the resulting pressure forced the head open again and released a vapor and liquid stream, which was then ignited by an ignition source in the hood. The student was burned on the neck, arm and leg, but the use of eye protection resulted in no eye injury. The other solvents–improperly stored in the hood at the time–ignited, resulting in extensive damage to two labs and an instrument room, as well as smoke and water damage from the fire sprinkler system in the building. Fortunately, the injured student recovered, but the resulting explosion and fire destroyed most of the laboratory equipment.
For this accident, a PHA would have identified:
National Renewable Energy Laboratory (NREL)
- How to verify proper operation and maintenance of the safety relief valve so that the highly flammable benzene vapor could safely vent from the distillation unit
- Other potential hazards when developing the SOP
- Additional personal protective equipment (PPE), such as use of flame retardant clothing, required when working with flammable material
In 2003, a Department of Energy scientist was performing general laboratory cleanup following the completion of an experiment involving the use of pyrophoric materials inside a glovebox filled with helium. The inert helium gas prevented the exposure of the pyrophoric materials to air.
The experiment SOP required pipettes containing tris (trimethylsilyl) phophine (a pyrophoric) to be inerted using a solution of indium trichloride inside the glovebox before removal. From the investigation, the scientist may have not completely inerted the material before removing the pipettes and placing them into a fume hood.
Even though the SOP did address the need to place the pipettes in a clean area of the hood, it did not identify the need to remove other flammable materials from the hood nor did it identify the hazard of putting the pipettes into a plastic waste container. As a result when air contacted the pyrophoric materials, the container and surrounding chemicals in the hood ignited, resulting in a loss of the hood and associated equipment inside the hood. While much of the damage was confined to the hood, a lack of detection and suppression systems inside the hood resulted in smoke damage to the lab before the detection system in the lab responded.
The investigation faulted the SOP prepared for the project for not adequately addressing the potential hazards associated with the cleanup phase of the experiment as well as engineering controls. For this accident, a PHA would have identified:
Texas A&M University, Chemistry Building
- Potential risks associated with improperly inerting the pyrophoric material
- Use of disposal containers made of noncombustible materials
- Containers of flammable chemicals and cleaning materials inside of the fume hood
- Fume hood equipped with suppression and detection systems not appropriate for pyrophoric materials
In 2006 at the Texas A&M University Chemistry Building, a liquid nitrogen cylinder inside the lab had a catastrophic failure. The blast damaged the lab floor and an underlying structural beam between the second and first floors. Since the main force of the resulting blast wave was directed upward and outward, the nitrogen cylinder shot through a 24-inch hole in the concrete ceiling and into the upper mechanical room, where it caused significant damage to the pipelines. The outward blast wave also destroyed a fume hood and blew an associated wall, door, and door frame into an adjacent hallway. Chemical containers failed resulting in widespread contamination. Additional contamination occurred as a result of broken waterlines in the upper mechanical room.
The investigation revealed that an unauthorized tank repair had apparently resulted in the removal of both the rupture disk and the pressure relief valve. The safety devices had been replaced with bolts to seal the holes in the tank. The investigation could not determine whether the devices had been replaced simultaneously or as a result of their failure over time. Regardless, the removal of the relief devices coupled with over pressurization resulted in the failure of the tank. The lack of corrosion inside the inner and outer tank walls further bolstered the investigating teams’ conclusions. Fortunately, the accident occurred in the early morning, and the building was not occupied.
For this accident, a PHA could have identified:
- Potential risks and critical nature associated with conducting repair work on pressure relief devices
- What the equipment should look like, so that any improper repairs would be recognized and corrective measures taken
- A Management of Change (MOC) procedure that would have identified the proper replacement device
- Maintenance was needed for the tanks. This may have prompted incorporation of the Compressed Gas Association’s preventive maintenance guidelines into the laboratory SOP.
Could a PHA or JHA have made the difference?
After a review of these three accidents and their investigation findings, the answer to this question is yes. Conducting a PHA or JHA could have made a difference in not only the magnitude of the damage caused but also may have prevented the critical failure that caused the catastrophic events and injury to lab personnel. Certainly, it is impossible to address every event that might go wrong during a chemical process or to identify the hazards associated with every task down to the smallest detail, but many of the hazards could have been identified through a systematic process such as the PHA or JHA.
Both the PHA and JHA are effective tools to identify the potential hazards associated with chemical processes or job duties and result in reducing risk as much as possible. They should cover each major aspect of the task from beginning of the experiment planning or task initiation until the final cleanup of the experiment or the work is completed. Even a task as innocuous as placing a metal bolt in a hole in tank, putting small pipettes in a plastic bin, or contaminates plugging a flow valve, can result in life-threatening events.
These tools are basic principles for industry, and can be applied to the laboratory setting to minimize risk and eliminate hazards. It is worth your time and effort to learn these fundamental principles and apply that knowledge for a safer and healthier laboratory workplace.
Final Report: Injury and Fire Resulting from Benzene Vapor Explosion in a Chemistry Laboratory Frederick Reines Hall, 2001, University California, Irvine, 39 pp.
Job Hazard Analysis (OSHA 3071), 2002, http://www.osha.gov/Publications/osha3071.pdf
Lessons Learned: Pyrophoric Materials Cause Chemical Fume Hood Fire, 2003, Lawrence Livermore National Laboratory, LL-2003-LLNL-20, 3pp.
Investigative Report on Chemistry 301A Cylinder Explosion, 2006, by Brent Mattox, CIH, Environmental Health and Safety Department Texas A&M University, 31pp.
Paul Cotter is a unit manager in the Texas Tech Department of Environmental Health and Safety
Renee Witherspoon is a section manager in the Texas Tech University Health Sciences Center Safety Section