“About 5:30 PM there was a loud bang from the oven. Sylvia opened the oven door and the Pyrex dish had shattered into a million pieces…”

TRUE says Snopes.

Consumers have been noticing for years that sometimes their Pyrex brand cookware unexpectedly breaks during or shortly after use, often with such shatterings occurring in rather eruptive form. It is not unheard of for a Pyrex dish to suddenly “explode” while sitting in a hot oven or soon after it has been taken from one and is resting on a counter.

As to what might be the cause of so many shatterings, one possible explanation is that while Pyrex products were originally made of borosilicate glass, the company’s products now vended in the North American market are fashioned of tempered soda-lime glass, a cheaper material.

To see the video "Testing Pyrex: Experts Weigh In," please see this link.