Arizona explosion underscores potential hazards posed by ESS technology, and the need for more responder education

Blog Post created by andrewklock Employee on Apr 22, 2019


This past Friday evening, eight firefighters were injured when an energy storage system (ESS), which was connected to a solar panel array and operated by Arizona Public Service Company (APS), was involved in a fire and subsequently, an explosion. According to media sources, responders were called to the scene in response to a smoke condition from an ESS container. When they arrived on-scene, they saw white smoke billowing from a Conex container and called a hazardous materials unit to respond. Soon after they inspected the container, an explosion took place that blew the heavy metal doors off their hinges. Injuries sustained by the first responders included both thermal and chemical burns, as well as multiple fractures, lacerations, and a collapsed lung. As of the writing of this blog, one responder was critically injured and two others were seriously injured, however all three are reported in stable condition. Thankfully the remaining five have been released and are recovering at home.


This incident is a reminder of the challenges faced by first responders as new technology such as ESS are mainstreamed into everyday living. Use of ESS is growing not only in the U.S. but also on a global scale, as renewable energy is implemented around the world.  These systems are showing up in myriad environments, including residential homes, commercial buildings, hospitals, and dedicated utility operated sites, like this installation.


Since 2014, NFPA has been working to identify the hazards associated with this emerging and growing technology.  Research from the Fire Protection Research Foundation (FPRF), expansion of ESS criteria in NFPA 1, Fire Code, development of our new NFPA 855 stationary energy storage standard, and the construction and deployment of the U.S.’s first Energy Storage and Solar Safety training program for first responders demonstrate NFPA commitment to providing and sharing the knowledge necessary to help with the design and ongoing operation of ESS, regardless of the size or location of the system. (On that note, the Boston Fire Department and other departments in the greater Boston area are attending an ESS training at our headquarters today.)


Equally, if not more important is the need to offer first responders the information and education they need when they encounter a fire event or incident at an ESS facility. ESS owners, operators, and designers for these facilities are encouraged to utilize the resources provided by NFPA to ensure that the best design and installation practices are being followed.  Pre-planning and coordination with the first responders is a critical need, since ESS technology can vary between battery chemistries, arrays, and location options.  Firefighters need to be aware of the underlying hazards in these environments and the additional precautions that need to be taken when conducting operations involving ESS. NFPA offers free online self-paced training, as well as classroom training, interactive scenario modeling apps, and reference materials so knowledge about these systems can be propagated.     


NFPA has consolidated all of our available resources at  Many of these materials are readily and freely available to all members of the public and responder communities.  This Arizona event and the serious dangers it revealed for the firefighters involved allows all of us to pause and step up our efforts on educating the broader fire protection community about ESS .  It is also a good reminder that as new technology comes into our lives, new potential hazards often follow.  Raising awareness of these hazards and offering solutions is a fundamental part of NFPA’s mission.