These days we hear all these stories about how bad this plastic is and how bad that plastic is but what does it all mean and where can I see what kind of plastic it is?
Let me start by telling you how you can distinguish the type of plastics out there. Plastics are put in different classes each given a different number, and that number is placed on every plastic product.
A product will carry a symbol, similar to the one depicted on the left here, that tells you what kind of plastic it is, this way it is possible to decide if you want this plastic and it makes it easier for the recyclers to see what kind of plastic they are dealing with.
And with more and more bad stories about plastics it is important to know what the numbers mean and if the plastic at hand is safe.
Here, we have tried to collect as much information as we can on plastics, their symbols and safety. We are aware that this list is not perfect and that there is more to know, however it provides a good starting point for you to make some kind of judgement based on the information.
let’s sort them out based on numbers:

Polyethylene Terephthalate (PET / PETE)
This plastic seem to be one of the safer ones. The PET plastic is used for things like pop (soda) bottles so most us us come in contact with them on a regular basis. There are stories about leaching of chemicals with these bottles but the main concern here seem to be when you reuse the bottle.
Online there are some stories about them leaching phthalates and bisphenol A and they carry serious health risks.

High Density Polythylene (HDPE)
This plastic is used in things like Milk and Juice Jugs and till now seem to be fairly safe to use. I didn’t find bad stories about it yet. Although leaching is also an issue for this plastic so be careful what you store in it.

Polyvinyl Chloride (PVC)
PVC doesn’t have a good reputation at all but still it is used in all kind of things around the house. From plastic window frames to plastic shower curtains. It is also used in food related items such as like meat packaging which could do direct harm to you. PVC plastic seem to be extremely bad for your health with all kind of cancer related effects to your body.

Low Density Polyethylene(LDPE)
This plastic seem to be safe till now or let me say it like this I didn’t find any bad rap about it.
LDPE plastic (nr 4) is often used for things like bread bags, milk bags and grocery bags. Of course they fill up our landfills so even though these are not directly harmful, they hurt the environment, please recycle your plastics!

Polypropylene (PP)
Although most of the information out there states this plastic as safe, some information I ran into states that there are health risks with the nr 5 plastic. Polyproylene can be a risk for disease related with the gastrointestinal tract, liver and respiratory system.
Polypropylene is used in products like margarine tubs, ketchup bottles and for more durable uses in products like appliance parts, etc.

Polystyrene (PS)
A commonly used plastic for instance in the famous styrofoam cups and boxes in restaurants to serve as doggy bags. Polystyrene is known for leaching it’s toxins into the contents of the container, and the chemicals used for polystyrene plastics are known to be damaging to health and the reproductive system in humans.

Plastic number 7 refers to all “other plastics” and that makes it also one of the most dangerous of all the plastics. Often the plastics in this category contain the chemical Bisphenol A BPA and this man made chemical and acts like a synthetic estrogen (a reproductive hormone found in both men and women). Surprisingly, metal cans are often lined with the nr 7 plastic to afford durability.
This plastic is often used in strong colorful plastic products such as water bottles, plastic cups and storage containers. It is probably one of the most harmful plastics on the market specially because of Bisphenol A that has the tendency leach out of the plastic the more you use it or heat it.
Conclusion:
After reading about all those plastics one can basically only come to one conclusion and that is to use plastics in items involving foods and drinks as sparingly as possible. In my opinion glass is the best replacement but it has some obvious disadvantages, as it is is more likely to break or chip. For water bottles you can look at metal bottles they are not so handy as the plastic ones, but for me my health is more important then how cool my water bottle looks.
In summary, the general trend states that plastics 1, 2, 4 and 5 are OK and plastics 3, 6 and 7 are bad.
I hope this article helps you decide what to do with the plastics in your life, however be cautious, the information about what is good or bad seems to change from day to day.
Helpful Resources:
Green Learning: Plastic by the Numbers
Bottle Racket
Plastic Chemicals found in Canned foods
Plastic bottled water bad for the planet
Another Plastic Story