Toughened Glass

While toughened glass is truly tough and long lasting, it sometimes does shatter – frequently with a dangerous and frightening bang.

Fortunately injuries are rare. The glass usually breaks into small square fragments, which are much less likely to cut than the jagged pieces from other kinds of glass. The fragments of glass are similar to those from a shattered car windscreen.

However, any shattered glass can still cut you, so be careful when handling and remember:

Toughened glass is not unbreakable!

How is the glass toughened?

Toughening is done by a process which compresses a thin surface layer of the glass. While this makes the glass item much more resistant to pressure or impact, a small surface chip or scratch weakens this surface layer. The chip or scratch may be small, but this is what can cause the glass item to shatter.

What can you do?

You should examine items of toughened glassware occasionally, and dispose of any that are chipped or scratched.

Toughened glass may be weakened by thermal shock, so you should avoid extremes of temperature like putting very hot food on a glass plate that has been in the fridge.

What we can do if there is a safety problem

If you have had a problem with toughened glassware, the Ministry of Consumer Affairs would like to hear from you.

The Ministry may consider taking action if the incidence of shattering of toughened glassware increases.

PDF of publication/Ordering publication

The Toughened Glass factsheet is now available online in PDF format (73 KBs). Instructions for obtaining the Adobe Acrobat viewer.

The printed factsheet can also be ordered using our online Publications Form.