Earlier this month, a coroner in the United Kingdom revealed that a 32-year-old man with an iPhone electrocuted himself in a bathtub late last year while the device was plugged into an extension cord.

And just last week, an Alabama man suffered serious burns when the dog tags he was wearing made contact with the plug from his cell-phone charger.

Does that make your smartphone a major electrical hazard? Not really, according to John Drengenberg, consumer safety director at the independent testing organization Underwriters Laboratories.

As long as they're unplugged, phones, laptops, and other devices that use rechargeable batteries don't have enough power to kill you, he says, even if you were to drop one into a bath. (Although he does not recommend trying that.)

But once plugged into an outlet, it becomes a potential hazard. In fact, the Electrical Safety Foundation International, a nonprofit dedicated to educating the public about such hazards, estimates that almost 70 people per year die from electrocution incidents related to consumer products.

And unlike a hair dryer or electric razor—devices meant to be used in a bathroom—phones, laptops, and wireless speakers are not equipped with a safety mechanism known as a ground-fault circuit interruptor, which shuts off power to the device when it gets wet, much like a circuit breaker in a fuse box.

In the U.S., building codes require you to use outlets equipped with GFCI in bathrooms, kitchens, and other household spaces where an electronics device might come into contact with water. 

In the case of John Bull, who was getting ready for a holiday party in his home near London, the smartphone he was using in the tub was plugged into an outlet located outside the bathroom, which means it almost certainly did not have ground-fault protection. It’s likely that the cord itself fell into the tub, which delivered a fatal dose of current from the house wiring.  

In the case of Alabama's Wiley Day, the plug from the phone's charger apparently wasn't fully seated in the extension cord he was using, leaving the prongs exposed. Day was reportedly sleeping with his phone when his dog tags slipped between the charger and the extension cord. "My necklace became the conductor, " he told reporters for ABC affiliate WAAY.

Day was hospitalized with second- and third-degree burns on his neck and is expected to recover.

Although the two incidents involved Apple iPhones, they could have occurred with any smartphone, which is why consumers need to be careful. The manufacturer declined to comment on the mishaps but did stress the importance of employing approved charging devices as directed.

Ways to Protect Yourself From Electrical Hazards

Respect your phone: They seem like innocuous devices, but they can be dangerous, said Sean Cummings, the U.K. medical examiner who investigated Bull's death. So be mindful of those threats. Think twice before going into the bathroom with any device that’s plugged in, Drengenberg adds.

Use the right charger: Though it's not clear what type of cords or adapters were used in the Ball and Wiley accidents, a Chinese flight attendant was electrocuted in 2013 by a phone plugged into a faulty third-party charger. The incident prompted Apple to launch an education program, including a special discount for any consumer who took a third-party charger in for replacement.

Drengenberg's advice: Stick to chargers approved by the manufacturer. At the very least, make sure they have a UL mark signifying that they've been put through a UL certification process.

Test your ground-fault outlets: Drengenberg suggests taking 10 seconds each month to check your GFCI outlets. First push the "test" button. It should make a quiet popping sound. "At that point, anything that's plugged into the outlet should go dead," he says. "Then push the reset button and it should come back on. That's all that's required."

Don't depend on extension cords: They're not meant for long-term use. "If you're using them on a regular basis, you need more outlets," Drengenberg explains. He also warns against "daisy chaining"—plugging one extension cord into another—and against using the cords in a bathroom. "Don’t use an extension cord anywhere that it might get wet,” he says.

Seat your plugs securely: As Drengenberg notes, Wiley's accident was the result of a charger that didn't seat fully in the extension cord, leaving the electrified prongs of the plug exposed. This problem affects outlets as well, especially on a device that has a "wall wart" or similar "brick" near the plug. "Outlets do wear out, so if they're sagging instead of holding your plug securely, it's time to replace them," Drengenberg says.