QuoraEDThis is when we pick up a trending or interesting thread from Quora and spin a story around it. 

This time we would like to discuss interesting facts about plastic bottles. There has been a lot of controversy surrounding plastic, its use, its long-term ill-effects and its much-talked about, but fruitless, ban in Delhi.

There has been a hype about the acceptable micron level in plastic that can be used, but it is tough to find the micron level for all types of plastic. There is something better which can be used to find whether a particular plastic (particularly a can or bottle) is fit for use/re-use, and a Quora user Kasee Sreenivas penned it down very clearly.

Read on to find out.

Have you ever noticed these numbered triangles below the plastic bottles you use?

Do you know what the number inside the triangle represents?

I’ll tell you their significance.

  • Number 1 inside the triangle as shown in the above picture represents the plastic is made of Polyethylene terephthalate. (PET)

This plastic is safe for single use and should never be heated.

If you observe carefully, there’ll be a message on the cover saying:


crush bottle

These are commonly used for bottled water and soft drink bottles.

Please don’t use the bottle after its expiry date. The plastic disintegrates eventually after the expiry date. You’ll end up drinking water along with minute amounts of plastic which is very dangerous.


  • Number 2 inside the triangle represents that the container is made of High-Density Polyethylene. These plastics can be reused and refilled.

Commonly used for detergent, shampoos containers etc.

  • If you see number 3 inside the triangle, avoid the use of that plastic immediately. They contain carcinogens (these plastics are made of PVC).

Commonly found in peanut butter jars.

  • You can reuse the plastic if it has number 4 inside the triangle. These are commonly used as reusable bags, especially for shopping.

Common usage: Grocery store bags, plastic wrap, dry cleaning bags, shopping bags etc.

Read More: 10 Interesting Facts About North Korea’s Intercontinental Ballistic Missile

  • Number 5 inside the triangle is the safest. You’ll find it in ice creams cups, straws, and syrup bottles.


Common usage: Medical storage, food storage.

  • Number 6 inside the triangle is dangerous and number 7 inside the triangle is deadly. PLEASE AVOID

They are made of polystyrene and polycarbonate BISPHENOL A (BPA).


Continuous usage might lead to cancer, heart diseases.

Common usage: Plastic spoons, plastic forks, water bottles (mostly used by athletes).

For those who are asking “TUPPERWARE having 7 inside the triangle, is it safe or unsafe?”

Here you go..

Wine glass and fork symbol printed on the plastic container:

A wine glass and a fork symbol is an international symbol for ‘party safe’ material. The symbol identifies that the material used in the product is safe for food contact.

You can use the plastic container if it has this ‘party safe’ symbol on it but if this symbol is printed along with number 6 triangle, be cautious.

You don’t need to remember those chemical names. Just remember which numbers/symbols (inside the triangles) are safe to use and which are not.

I don’t know whether you know this or not but you should know this :)

Now it’s your turn to educate other people!

Image Credits: Google Images

While you are at it, you might also like this other post from our QuoraED section:

QuoraED: How Horrible It Is To Meet Katrina Kaif In Person? Well a lot!


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