The article “Fire at Arizona Energy Storage Battery Draws Scrutiny” (ENR 7/8-15 p. 18) illuminated the potential hazards associated with energy storage systems and lithium-ion batteries and accurately noted that the technology “now make[s] up 98% to 99% of all new battery-type storage systems.”

Near-ubiquitous use of these devices makes it critically important to recognize risks they present to people and property. In particular, first responders, who may encounter hazmat issues, thermal runaway concerns, battery explosion and reignition and off-gassing may find themselves in dangerous situations.

To that point, it was surprising to see that the article downplayed the impact of the April 19 energy storage system (ESS) explosion at the Arizona Public Service Co., stating that injuries sustained by eight firefighters and a police officer were “non-life threatening.” Of the firefighters injured, three required an extended hospital stay. The most serious injuries included a firefighter who had a “nose fracture, skull fracture, collapsed lung, rib fractures, broken tibia and fibula and an artery cut in his left leg.” Others sustained multiple fractures, burns and concussions.

The article also seems to minimize inherent ESS hazards, stating, “What we’re learning over time is that it’s not necessarily always a battery problem.” The hazard lies with the battery chemistry; thus, trying to direct attention away from that aspect can be dangerous. 

As with so many new and emerging issues, it is important to develop corresponding information to better educate audiences about risks and about measures needed to ensure that systems are designed properly and are safely handled in the event of a fire or other emergency.

The National Fire Protection Association is set to release NFPA 855, Standard for the Installation of Stationary Energy Storage Systems, in early September. It provides requirements based on technology used in energy storage systems, the setting where the technology is being installed, the size and separation of ESS installations and fire suppression and control systems that are in place.

NFPA also has added ESS resources, including online training for the fire service, key research that is educating a broad range of stakeholders and other related content that can be found on our website at

We appreciate coverage of the incident in Arizona. It is an important way to inform first responders, utilities and design and construction communities about the numerous risk factors and to help ensure that ESS hazards are recognized and minimized moving forward.

Chris Dubay
Vice President/Chief Engineer
National Fire Protection Association