Storing bottled water in your car during the hot summer months can be more dangerous than you might think. In July 2017, Dioni Amuchastegui, an Idaho Power battery technician, discovered this firsthand when his parked truck began to smoke. “At first, I thought it was dust,” he explained, “but then I noticed light was being refracted through a water bottle, and it was actually smoke.”

Amuchastegui quickly moved the bottle before it caused significant damage, but the incident left him stunned. He later replicated the scenario with his Idaho Power team, demonstrating how sunlight, passing through a clear water bottle, can focus heat enough to start a fire.

David Richardson, a spokesperson for the Midwest City Fire Department in Oklahoma, explained, “The conditions must be just right… but in seconds, that focused beam can reach temperatures of 400 degrees.” This heat is enough to ignite a fire in your vehicle.

To stay safe, don’t leave bottled water in your car on sunny days. Instead, take it with you, and consider using reusable water bottles.