They consume electricity even when the device is not charging. "I was just scared because all I saw was the flames and my son was laying there," Johnson said. These devices need areas to be ventilated," Hamden Fire Chief David Berardesca told the local NBC affiliate. "It is recommended that you leave these types of devices on a hard surface so the heat can dissipate. The batteries heat up, they could melt – in some cases, explode – and cause a fire."
– A tip from the NYPD: "Don't put your cellphone under a pillow when sleeping or when charging your device"—unless you want to set your head on fire. Deputy Inspector Wilson Aramboles of the NYPD's 33rd Precinct shared that message on Twitter on Monday alongside photos of a charred phone, battery, and pillow. It isn't clear if the photos are tied to a recent accident or an old one; Gothamist reports they might be from a 2014 incident in which a Texas teen's Samsung Galaxy S4 started a fire under her pillow. Either way, they "really do drive home the point," notes the San Francisco Chronicle. Cell phones need room to breathe, especially as they heat up while charging. While keeping a hot phone away from flammable materials like a pillow might seem like a no-brainer, some people choose to sleep with their phones nearby and rely on features like vibrating alarms. "It is recommended that you leave these types of devices on a hard surface so the heat can dissipate. The batteries heat up, they could melt—in some cases, explode—and cause a fire," a fire chief told NBC Connecticut last May after a teen's phone set fire to his bed. (An exploding cell phone actually killed a man in China.)