While hundreds of millions of glass baking dishes are used
safely each year, hot glassware can shatter unexpectedly -- sometimes causing
serious injuries, according to a year-long investigation by Consumer Reports
(CR).
The report, which comes more than four years after ConsumerAffairs.com revealed the problem and jousted with bakeware company lawyers, details several stories of glass bakeware
breaking and shattering, including the case of a grandmother who said she
opened her oven to baste a ham on Thanksgiving Day, only to have the glass dish
shatter, sending pieces of glass and hot juices flying.
Investigation requested
After reviewing scores of consumer reports filed with
federal regulators about bakeware unexpectedly shattering, Consumers Union
(CU), the nonprofit publisher of Consumer Reports, has asked the Consumer
Product Safety Commission (CPSC) to conduct a thorough
study of glass bakeware on the market.
CU has also called on manufacturers to imprint warnings that
are clearer and more prominent on their bakeware. "Part of the problem is that the fine print warnings are so tiny
and they're part of the packaging that consumers often throw out," said Andrea
Rock, senior editor, Consumer Reports.
The report, available in the magazine's January issue, says that in a typical year, the two main manufacturers of glass
bakeware -- World Kitchen, the maker of Pyrex in the U.S., and its competitor,
Anchor Hocking -- collectively make on average more than 70 million units of
what is undoubtedly a staple of most kitchens and a popular cooking tool when
preparing holiday meals.
Caution for cooks
The report contains ten precautions that may surprise cooks
who have used glass bakeware. To
minimize the chances of the glassware shattering, consumers should read and
save the safety instructions from their glass bakeware and follow these safety
rules:
- Always place hot glassware on a dry, cloth potholder or towel.
- Never use glassware for stovetop cooking or under a broiler.
- Always allow the oven to preheat fully before placing the glassware in the oven.
- Always cover the bottom of the dish with liquid before cooking meat or vegetables.
- Don't add liquid to hot glassware.
- If you're using the dish in a microwave, do not use browning elements, and avoid overheating oil and butter.
- Do not take dishes directly from the freezer to the oven or vice versa.
- Never place hot glassware directly on a countertop (or smoothtop), metal surface, on a damp towel, in the sink, or on a cold or wet surface.
- Inspect your dishes for chips, cracks, and scratches. Discard dishes with such damage.
- To avoid risks associated with glass dishes, consider using metal bakeware for conventional and convection ovens.
CR's investigation
To find out about glass bakeware, CR conducted an
investigation that included testing in its own labs and outside labs, and
gathering information from manufacturers, government agencies, experts, and
consumers. When Pyrex was first
marketed in 1915, it was made of a heat-resistant glass called borosilicate
that previously was used to prevent glass railroad lanterns from
shattering.
While U.S. manufacturers of both Pyrex and Anchor Hocking
have switched from borosilicate to soda lime glass for their glass bakeware,
the magazine notes, samples of European-made glass bakeware obtained continue
to consist of borosilicate.
The manufacturers say their soda lime glass has advantages
and is less likely to break when dropped or bumped. While the results from Consumer Reports' limited impact tests
were highly variable, some samples of soda lime glass showed the highest impact
resistance.
The methods
Consumer Reports tested both types of glass in its lab to
see how they compared in extreme conditions likely to cause breakage. To test
the dishes, CR filled each pan with dry sand (which gets much
hotter than food) and then placed the dishes in ovens set at varying
temperatures. The testers then compared
what happened when each hot dish was removed from the oven and placed on a wet
granite countertop, a situation likely to induce thermal shock and contrary to
each manufacturer's instructions for use.
The magazine notes that the bar was set high in the extreme
tests because dishes that are scratched or damaged may not offer the same
safety margin as new dishes, and users may ignore or be unaware of the usage
instructions.
Ten out of ten times the soda lime glass broke after baking
at 450 degrees. But in the same conditions, the European borosilicate glassware
did not break, though most did after baking at 500 degrees.
Highlights
Some key highlights from the investigation include the
following:
- Consumers in scores of cases reported glass bakeware
unexpectedly shattering, according to federal documents, court papers, and
interviews. When Consumer Reports
examined 163 incidents (152 of which were from CPSC files) in detail, the
analysis revealed 42 reports of injuries, ranging from minor burns or cuts to those
requiring surgery. More than half of the incidents reportedly occurred while
the bakeware was in the oven while almost a quarter occurred with the bakeware
cooling on a counter or stovetop.
- When glass bakeware does shatter, consumers say, it can break into sharp shards that go flying, raising the risks of injuries. This contrasts with claims from one of the manufacturers that its glass bakeware breaks into "relatively small pieces generally lacking sharp edges.
Michelle of New York, NY, says she was cooking BBQ turkey legs in a 375 degree oven
using Anchor Hocking
glass lasagna
pans. "When I went to take it out," she writes ConsumerAffairs.com.
"It exploded and shards of glass when flying everywhere. They even flew
into my face and luckily I didn't get anything in my eye how ever in the
process of cleaning up the mess, I cut my foot. Thank God my kids were not in
the room when it happened."
"I placed a pork loin into my Pyrex dish and put it in a
425 degree oven," writes Megan of Newport News, VA. "Eight minutes
into cooking I hear an explosion. I open my oven to find tiny pieces of glass
EVERYWHERE and my pork loin lying on the oven rack. So glad nobody was around
and the oven door was closed tightly when it happened. Beware!"
Recommendations
Consumers Union says manufacturers should imprint clearer
and more prominent warnings on their bakeware, not just on the packaging that
gets tossed upon first use.
While hundreds of millions of dishes are used safely each year, CU believes the situation is serious enough that it has asked the CPSC to conduct a thorough study of glass bakeware on the market, with particular attention to the difference between bakeware made of soda lime glass and borosilicate.
