Sammy, how scary! I prefer glass, but it never occurred to me it might do that. Is it a fairly new dish? I found this...

Consumers we spoke to said there was no doubt their product was a Pyrex dish. They had all bought the dish within the past few years  since Corning, the original manufacturer of Pyrex, licensed the name to World Kitchen in 1998.

The four glass experts ConsumerAffairs.com consulted for this story agreed that the most likely reason the dishes are exploding is that they are not made from the type of glass, known as borosilicate, that they said was originally used in Pyrex dishes.

"The composition of Pyrex was changed," Freiman said. "What we don't know is whether it was changed prior to Corning selling this to World Kitchen or not. ... When the composition was changed they made it, what I would suspect, is a less expensive raw materials to put into it, a less expensive process."

World Kitchen denies that the products were ever made of borosilicate.

Pyrex dishes are made of tempered soda lime glass, which is the same glass used in car windows and many other consumer goods. Tempered soda lime is not designed to withstand extreme temperature changes the way borosilicate is, said Dr. Delbert Day, a professor of materials science and engineering at the Graduate Center for Materials Research at the Missouri University of Science and Technology.

"(Borosilicate) has a lower thermal expansion coefficient than soda lime," Day said. "It is less likely to break during thermal shock. There's also a much larger body of experience in using tempered borosilicate glass for cooking purposes than tempered soda lime."

"Soda lime glass is less expensive to produce than a borosilicate glass and it starts with the raw materials," said Day, who also owns a company that manufactures glass medical products. "The raw materials in a borosilicate glass, particularly the boron component, are more expensive than the components in a soda lime. Also, it can take a higher temperature to melt the composition so there's expense there."

Here is a link that might be useful: Consumer Affairs

Sammy, I'll bet your dog heard the high-pitch of the glass cracking and that is why he whined. They can hear pitches that humans can't. I'm glad that your son wasn't hurt when it cracked.

I had a 13X13 baking dish that had the upper-end crack off several years ago. Such an odd place; it's really thick there. I now use Pampered Chef products almost exclusively. I've only had the flat baking sheet crack several years ago, and it was my own flat...I set it on top of a hot burner and it cracked it right down the middle.

Glad you posted this..I wasn't aware about the cheap materials used in Pyrex. Good to know; thank you!
-terry

So, it sounds as if the originals are worthy and the recents aren't.

I have been using some of the pottery-like baking dishes made by Le Creuset because of recommendations on Chowhound that they cleaned up (cheese enchilladas with sauce topped with cheese) really well. They do clean up really easily and the shape is easier to serve from. I'm moving towards a Hang-the-cost, does it cook and clean well point of view. (And I can draw comparisons with gardening.)