Consumer Alert: Be aware of exploding glassware

Published 7:28 am Friday, December 24, 2010

It was a typical Sunday for Laura Mitchell.

On Dec. 12, the Colerain resident was in her kitchen preparing a meal for company that was on their way over.

What Mitchell didn’t know was that a potentially dangerous situation was about to unfold in her home, one that has occurred in several homes across the country.

Cube steaks were on the menu that day and after browning them in a pan on the stove top, Mitchell placed the meat in a glass baking dish and placed it in the oven at a temperature above 400 degrees. After preparing gravy to pour over the steaks, Mitchell opened the door to the oven.

What happened next came as a shock as the glass baking dish containing the steaks literally exploded.

“It sounded like a gun shot,” she said. “It broke all to pieces. It exploded all over the place.”

Instead of having a nice Sunday dinner with her guests, Mitchell now had a complete mess on her hands. Shards of glass were strewn across the bottom of the oven and the cube steaks were now a waste.

“I had to throw it away, a three pack of cube steak,” she said.

Mitchell doesn’t remember the brand name of the baking dish, but said it was around two years old and had been purchased at a local grocery store.

As frightening as Mitchell’s experience was, there have been many reports of bake ware, such as Pyrex and Anchor Hocking, unpredictably exploding.

While hundreds of millions of dishes are used safely each year, a year-long Consumer Reports investigation found that hot glassware can shatter unexpectedly.

Consumer Reports, an independent non-profit organization, has investigated 152 incidents, some that included serious injuries, involving exploding glass bake ware that were reported to the Consumer Product Safety Commission.

“Pyrex has changed over the years. It used to be made of a type of glass called borosilicate, and so did Anchor Hocking bake ware,” said Consumer Reports’ Andrea Rock. “Now, they’re both made of a kind of glass called soda lime.”

American manufacturers say soda lime glass has advantages as it is less likely to break when dropped or bumped.

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 bake ware from Pyrex and Anchor Hocking. Also in the tests were European-made Pyrex and Arcuisine Elegance, both made of borosilicate.

All of the dishes have warnings to avoid extreme temperature changes. Packaging on the American-made products contains many more cautions in fine print.

“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,” Rock said.

As part of the lab tests, the glassware was filled with dry sand, which gets far hotter than food. Testers put the dishes in a 450-degree oven for 80 minutes, then took them out and immediately placed them on a wet granite counter top.

Ten out of 10 times, the soda lime glass broke. But in the same conditions, the European glassware did not break, although most did after baking at 500 degrees.

“Our advice is: follow directions carefully,” Rock said.

Consumer Reports suggests using metal pans to avoid the risk entirely.

Both Anchor Hocking and World Kitchen, which makes Pyrex in the U.S., say that, compared to the hundreds of millions of pieces of glassware in American homes, they have very few complaints about exploding glassware.

But Consumer Reports says it believes the number of cases is high enough that the Consumer Product Safety Commission should investigate.

Anyone who experiences a problem with exploding glass bake ware is encouraged to contact the Consumer Product Safety Commission at or 1-800-638-2772.

You can see a video of the lab tests done by Consumer Reports at