When off-gassing gives way to smoke generation, you are at the tipping point. You must transition to containment strategy/defensive operations appropriate for Stages 3 and 4.

Once batteries have failed and thermal runaway is under way, expect a long-term incident with high-volume toxic and explosive gas production, the potential for re-ignition hours or even days after initial extinguishing, and the need for a sustained high-volume water supply.

Pursue slow and methodical containment actions, and consider the following additional tactics as appropriate:

• Expect smoke generation to cause ignition.
• Prepare for deflagration: rapid burning that may create a significant pressure wave, similar to an explosion.
• Construct an incident action plan for extended operations.
• Establish a high-volume water supply.
• Identify and protect external exposures and prepare for a multiple operational period event.
• Remember that battery banks will continue to retain stranded energy and pose an ongoing re-ignition and shock hazard, even days after initial suppression.