Glass Bakeware Shattering

FRESNO, Calif.

Patricia Szczcenia says three years ago on Thanksgiving she went to baste a ham that was roasting in a Pyrex dish. She was stunned at what happened next.

"It exploded. I mean all over the kitchen. I mean, there were glass shards from wall to wall."

Pyrex says it can't confirm the kind of glassware Patricia was using because she didn't send the shards to the company. Consumer Reports' Andrea Rock investigated her case, along with 151 other incidents involving glass bakeware that have been reported to the Consumer Product Safety Commission.

Andrea: "Pyrex has changed over the years. It used to be made of a type of glass called borosilicate. Now it's made of a kind of glass called soda lime."

Consumer Reports tested both kinds of glass in its lab to see how they compare in extreme conditions likely to cause breakage. The tests included brand new 13-by-9-inch bakeware from Pyrex and Anchor Hocking. Also in the tests, European-made Pyrex and Arcuisine Elegance -- both made of borosilicate.

All have warnings to avoid extreme temperature changes, and packaging on the American-made products contain a lot more cautions in small print.

Andrea Rock: "Our test was contrary to the instructions, but we set the bar high because people may not be aware of the instructions, and dishes that are scratched or damaged may be more susceptible to shattering."

In Consumer Reports' very tough lab tests, the glassware was filled with dry sand, which gets far hotter than food. It was put in a 450-degree oven for 80 minutes, and then placed on a wet granite countertop -- something you're not supposed to do. Ten out of ten times the soda lime glass broke. But in the same conditions, the European glassware did not break, though most did after baking at 500 degrees.

The American manufacturers say soda lime glass has advantages and is less likely to break when dropped or bumped. Consumer Reports advice is to follow direction carefully or use metal pans to avoid risk entirely

Both Anchor Hocking and World Kitchen, which makes Pyrex in the U.S., say the number of breakage complaints they get from consumers involves a very tiny fraction of the hundreds of millions of pieces of glassware in American homes. But Consumer Reports says there are enough cases to warrant further investigation by the Consumer Product Safety Commission.

If you have a problem, Consumer Reports says report the incident to the CPSC at 800-638-2772 or

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