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The variety of plastics in our lives is astonishing. Everything from telephones to stockings is manufactured from this group of synthetic substances, but most are safe.
Here's a few to watch out for:
PVC is normally a harmless rigid solid and used in house gutters and pipes.
To make it rubbery, plasticisers such as chemicals called phthalates are added. These plasticisers can leach out over time.
Studies on fish suggest that, at high levels, they may act as weak sex hormones. In humans it is thought that phthalates may interfere with the body's usual way of regulating functions with hormones — the endocrine system.
Therefore plasticised PVC is not suitable for products that children might chew.
For items such as baby bottle teats, silicones are the main plastic used today, and these materials are safe. Rubbery toys may use other materials that are naturally rubbery, without plasticiser, and are safer to chew.
PVC has also had a bad rap because its high chlorine content means some nasty by-products can be created during its manufacture and if it is incinerated.If you want to know whether your plastic has any chlorine in it, here is a simple test.
- Take a piece of bare copper wire (or strip some insulated wire).
- Hold its end in a cloth to protect your fingers and heat it to red heat in a flame from a gas burner, moving it up and down a little, until the flame no longer shows any colour (other than a little bit of yellow from harmless sodium).
- Touch the plastic with the hot wire, so that a little plastic sticks to the wire.
- Reinsert the wire into the flame. If the plastic burns with a greenish flame then there is chlorine in your plastic.
Teflon (PTFE) plastic is used in non-stick cookware. It is inert and non-toxic.
It does begin to deteriorate if heated above 235ËšC and decomposes above 350ËšC. Cooking oils and fats smoke at around 200ËšC and meat is fried at between 200ËšC and 230ËšC.
So, unless you make a habit of deliberately heating empty cookware full on, there is no problem.
The chemical used to make Teflon, however, is another matter. Known to chemists as PFOA (perfluoro-octanoic acid), it's a "likely carcinogen" according to the US Environment Protection Agency and it is very closely controlled during its manufacture.
PFOA is NOT present in the final product of Teflon. However, PFOA and similar compounds were, until recently, used in carpet and furniture dirt-repelling treatments and other items, such as the packaging of microwave popcorn.
Most products have been reformulated. But it's not recommend that you use any stain-resistant treatment on carpets where babies are likely to crawl. Read the labels for PFOA and check with manufacturers for any polyfluoro compounds.