IOWA (CNN) - An Iowa family says its shower door mysteriously exploded.
"It shot out six, eight feet from the bathroom."
Teresa Albertson explains how her glass shower exploded into a million pieces Saturday.
It went from a normal tempered glass door to this in seconds.
Albertson's children say they heard the explosion from their rooms.
"You could tell that it wasn't really a falling sound. It was more of an exploding sound so you could tell that it didn't fall. It bursted."
No one was in the bathroom at the time.
"I never heard of it and then when we started looking at it online there are instances of this."
"They call it spontaneous breakage. They actually have a word for it."
In his 32 years in the business Doug Sassman says he has only seen this happen a handful of times.
He says while it's rare, he actually had another customer come in last week saying the same thing happened to them.
"They were sitting out in the living room and just heard a pop. She went in to look and see and it was already all over the ground."
He says there is not much of an explanation for why it happens. He says it has nothing to do with a flaw in the glass or installation error.
"If it was chipping or scratching or flaws all the tempered would break."
To demonstrate how hard it is to break tempered glass he hit this piece of glass several times.
When it finally did shatter, you can hear the tiny pieces popping.
That's because during the tempering process the glass crystallizing on the inside.
This makes it safer...so it can nick you, but not cut you severely.
Either way, Albertson says the explosion is still scary.
"I was disturbed that we didn't know about the possibility of this happening. We're just lucky that no one was using the shower or in here for another reason at the time."
Sassman says it's not the manufacturer's fault, this has happened to glass doors from several different companies.
He says he is replacing his customer's door with no charge.