Glassware shatters in kitchen tests

By | Posted - Feb. 14, 2011 at 10:03 p.m.

This archived news story is available only for your personal, non-commercial use. Information in the story may be outdated or superseded by additional information. Reading or replaying the story in its archived form does not constitute a republication of the story.

SALT LAKE CITY -- A local consumer science expert is urging cooks to exercise caution when using glass baking dishes following a national investigation by Consumer Reports that revealed the glassware can shatter unexpectedly -- sometimes causing serious injuries.

Glassware pans have become indispensable in the kitchen. They're very versatile -- going from microwave or oven, to counter, to dining table. Millions are used safely every year, but a drastic change in temperature can make them shatter.

Consumer Reports analyzed federal documents, court records and conducted interviews regarding 163 incidents of shattering bakeware. Forty-two of the incidents resulted in injuries, ranging from burns to cuts that required surgery.

Guidelines for using Pyrex
  • 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 fully preheat 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.

More than half of the incidents occurred while the bakeware was in the oven, although nearly a quarter occurred while the bakeware was cooling on a counter or stove top, the consumer publication reported.

In the Consumer Reports lab, the glassware was exposed to extreme heat, then placed on a wet granite counter. The glassware shattered into sharp pieces instantly 10 out of 10 times.

The tests show what can happen when, against manufacturers' guidelines, the glass cookware goes from extreme heat to a cold surface.

Marilyn Albertson, associate professor of family and consumer science for Utah State University Extension, teaches consumer and kitchen classes.

"We would caution consumers to be very careful," she says.

Pyrex, and competitor Anchor Hocking, changed the ingredients in the glass a few years ago and removed borosilicate. The material made the product "more durable, and strong and handled higher temperatures better," Albertson said.

Now the companies use soda lime in the bakeware.

"At least the consumers are saying, it's not as durable as it was in the past," Albertson said. "And they've had problems with it shattering with temperature change."

Albertson and Consumer Reports recommend consumers follow the instructions. Pyrex is using a print advertisement to reinforce the "dos and don'ts" of cooking with glass.

The company suggests you never place the cookware directly on a burner or under the broiler; add liquid prior to cooking; preheat the oven; and place hot glassware on a dry, cloth potholder.

It's important to note you do not need to stop using your glass cookware. Just be aware of where you're placing it when it's right out of the oven.

"I try to be very cautious in my behavior when I use it because of the warnings I have seen," Albertson said.

As a result of its investigation, Consumer Reports called on the Consumer Product Safety Commission to look into the problem. The magazine also recommends when you buy glass bakeware, be careful to read over the manufacturer's instructions.


Story written by Jed Boal, with contributions from Marjorie Cortez.

Related Links


    Catch up on the top news and features from, sent weekly.
    By subscribing, you acknowledge and agree to's Terms of Use and Privacy Policy.

    KSL Weather Forecast