It is dangerous, and here are ways to protect against it.
Rob Shaezline is quite a handyman. One day he was startled by a noise coming out of the external speakers of his iPod.
"We heard this real loud bang. We thought it was a loud cap or something like that," said Shaezline.
The bang he heard came from his alkaline batteries, and the same thing would happen a month later to batteries in his computer mouse.
"This loud bang came out of the mouse and I had remembered it had leaked on the other, so I quickly took the battery out and here it is, it started to leak out of the base of the battery," said Shaezline.
He's not the only one experiencing this problem.
One blogger posted pictures showing the underside of an exploded nine volt battery. He noted the battery exploded with enough force to pop open the piece of metal that covers the bottom of the battery.
That drew responses from a couple dozen others who reported similar problems.
One writing he heard a loud shot, thought it was a gun fire coming from AA batteries in a toy. Another said the batteries in his mouse would crack and pop at random.
We took these concerns to Elton Cairns, a chemical engineering professor at UC Berkeley.
"Anything that could cause a very rapid discharge of a battery can cause it to overheat. And have conditions necessary for a fire," said UC Berkeley Professor Elton Cairns, Ph.D.
Cairns said the main concern is with lithium ion batteries because those batteries contain highly flammable organic solvents that can cause fires.
"Anything that could cause a very rapid discharge of a battery can cause it to overheat and have conditions necessary for a fire," said Professor Cairns, Ph.D.
Lithium ion batteries which run too hot or that are left in a hot location are also a concern.
7 On Your Side called both Duracell and Costco, the store where Rob bought his batteries, and both offered to give him a refund right away.
