Um....
....This meme about shattering Pyrex has been making the rounds for some time, and like many memes, there is some truth - but as Mark Twain once said, "the truth with some stretchers."
First, a lot of Pyrex pieces have been made from tempered soda-lime glass since the 1940s; the change from borosilicate glass for all Pyrex pieces is not recent (borosilicate is still used in Europe).
Second, the Consumer Product Safety Commission (CSPC) has looked into the stories of exploding Pyrex. There are certainly some instances of Pyrex exploding, no argument there. But not a huge number, and when
Consumer Reports interviewed over 150 people who claimed thermally-caused breakage, they found that a number of those people admitted that their use of Pyrex was not in accordance with glass bakeware of any kind, including borosilicate.
Snopes.com has also looked into this story, and has found that some parts of the commonly circulated rumors are true, and some untrue. Here's a link, where you can read and judge for yourself:
Consumers claim Pyrex brand glass bakeware is now manufactured from a different material and thus more susceptible to breakage.
www.snopes.com