Cell phones can spark more than just conversations

FEDERAL WAY, Wash. -- We work, we play, we drive, walk, talk and eat with them.

Cell phones are so much a part of our daily lives, some of us practically sleep with them. But did you know these constant companions can actually start a fire? Or explode? OK, it's pretty rare - really rare - but it happens.

A teenager's phone in California exploded, sending battery fragments shooting around the room. A 911 operator's phone explodes in her pocket, while she's on duty in Ogden, Utah. And in Boston, a man's phone caught fire in his pocket.

And right here in King County, Alberto Szarko says the same thing happened to him.

"A weird noise and smoke started coming from my pocket!" he said.

Szarko wasn't doing anything weird -- ironically he was just shopping for fireplaces at a neighborhood Lowe's. And it happened - fast.

"I mean it was like a noise you know like a 'shoo!' " he said.

Szarko felt the heat, saw the smoke, and it was coming from his pants!

"Wow! I said, 'Oh my God!' " he recalled.

So what was in Szarko's pockets that might have started a fire? Just some money, two closed matchbooks, and his cell phone.

Now your first thought might go to the matches but University of Washington Professor John Sahr says, "the most compact source of a lot of energy in his pocket would be the battery in the cell phone."

Matches use friction to ignite. But the matchbooks in Szarko's pocket were closed, and still caught fire. So could the battery in Szarko's phone produce enough heat to light the matches?

As a test, Sahr checked the amps in an AA battery: "10 amps, that's a lot of current - that's a lot of current to get out of a little battery like this," he says. And the AA has a lot less energy than the average cell phone battery.

So what will that AA battery do to solder wire designed to melt at 400-500 degrees? It melted the entire wire!

And any kid can show you dozens of YouTube videos with 9-volt batteries sparking fire in steel wool.

So clearly batteries can produce heat -- but a cell phone battery?

"This is a lot of power in a small package," says spokesman Scott Wolfson with the Consumer Product Safety Commission. "So when it fails, it can be a very serious situation."

In rare situations, the CPSC says yes, cell phone batteries can cause fire, most commonly in four different ways. Here's how:

1. Jingling coins, or any metal, rubbing against the phone's battery terminal can create sparks.
2. Exposing the phone to intense heat -- like on a car dashboard or next to a heater.
3. Putting it under a lot of pressure - like at the bottom of a backpack or purse with heavy books on top of it.
4. Finally - one of the most common causes of a malfunction is using a battery that isn't meant for that type of phone.

Szarko figures it was the combination of coins and phone that started his pocket to light up. And while he laughs about the incident now, he came to the Problem Solvers because he wants people to take the warnings seriously.

And the CPSC agrees. The CPSC has seen only 75 reported incidents, but some of those have involved injuries and they are even investigating one death.

So while no one should freak out - you should remember that cell phones pack a bunch of power.