The 7 codes of Plastic

| Environment | October 08, 2017

The 7 codes of Plastic

This looks like “crystal clean pure water but is it really?”

The Plastics Identification Code makes it easier to understand how harmful each type of plastic can be. Our objective here is to help you decide when, how and if you will continue to use plastics with your food and water. What follows is a summary of key points for the 7 codes or types of plastic.





Figure 1: Codes identifying types of plastics Source: www.chemistryaustralia.org.au

PET (Polyethylene Terephthalate)

  1. PET is the most common form of plastic. It is used for making beverage bottles. Other uses include laminated sheets, packaging film and clothing.

These are clear and tough plastics. Repeated use of these products increases the risk of bacterial growth and they cannot be easily decontaminated. Reuse of these materials must be avoided. However, they are readily recycled.

PET is argued by the plastics industry as the safe but this scientific article by L Sax presents several research articles that indicate it leaks Thalates. “A growing literature links many of the phthalates with a variety of adverse outcomes, including increased adiposity and insulin resistance, decreased anogenital distance in male infants decreased levels of sex hormones and other consequences for the human reproductive system, both for females and males. Infants and children may be especially vulnerable to the toxic effects of phthalates.” (1)

Another toxin released from PET is antimony.(2) Antimony is abbreviated to Sb in this Canadian research article that compared watered bottled in glass compared to PET with a hundred fold increase in the presence of Sb in the plastic. (3)

Antimony can have many detrimental effects upon human health. We chose to look at the issue of poor sleep. An article in the journal of Environmental Research in 2017 (4) “…found that urinary antimony was associated with higher odds to have insufficient sleep and OSA.” It also noted that “… chronic antimony poisoning has been reported to cause sleeplessness. The prevalence of short sleep duration (<7h/night) has been reported to be 37.1% in the general US population, and obstructive sleep apnea (OSA) affects 12-28 million US adults. Insufficient sleep and OSA have been linked to the development of several chronic conditions including diabetes, cardiovascular disease, obesity and depression, conditions that pose serious public health threats.”

  1. HDPE (High Density Polyethylene):

HDPE is considered one of the safest plastics as they are most commonly recycled. Recycling HDPE is comparatively easier and cheaper.

They are hard, semi-flexible materials with a waxy surface. They are mainly used for making milk cartons, plastic bags, waste bins, picnic benches. These plastics are safe for reuse.

  1. PVC (Polyvinyl Chloride):

PVC is also known as “plastic poison”. PVC discharges many chemicals throughout its lifetime.

These are mainly used in making pipes, flooring, shoes, computer cables and various other consumer products. They are sometimes used in making food wrapping films and children’s toys.

PVC materials are not recyclable; however they can be reused. Their use in children’s toys and for food or water must be avoided as it can be harmful to our health. This is one of those plastics that stink and make some of us dizzy when we open up some presents made. Avoid this whenever you can but if you get one of these at least let it air outside for a few weeks before leaving it to give off toxic fumes in your child’s bedroom.

  1. LDPE (Low Density Polyethylene):

LDPEs are safer to use than most other plastics. However, they aren’t as commonly recycled because most current recycling methods aren’t able to recycle this type of plastic.

LDPEs are used in shrink wraps, plastic bags and squeezable plastic bottles as well as the bags used to package bread.

  1. PP (Polypropylene):

Polypropylene has various uses as it is heat-resistant, lightweight and durable. It is mainly used for storage containers to keep products dry and safe from other outside contaminants.

They are used to make food containers, chips bags, straws and even rope.

PP is not easily recyclable but more and more facilities have now started accepting PP for recycling.

  1. PS (Polystyrene):

Polystyrene is the most common plastic pollutant. It is the plastic used to make Styrofoam cups, takeaway food containers, plastic cutlery and egg cartons.

Polystyrene is very weak and breaks easily, which is why the pieces flow away and contaminate the environment. Many marine creatures have been found with PS pieces in their stomachs.

Polystyrene recycling methods are not highly available. PS also disperses carcinogens and other chemicals harmful to human health. For these reasons, polystyrene should be avoided as much as possible.

  1. Other:

This category includes other types of plastics such as polycarbonates (PC), nylons, resins, acrylics. These are the plastics used in agricultural piping, furniture fittings, baby bottles, car parts.

These types of plastics also leak chemicals, but there is a safe version of polycarbonate which can be used in making baby bottles. However, they may still be unsafe if heated.

It is best to avoid their use wherever possible. This category is where BPA lives. BPA is a xenoestrogen and has been found to be an endocrine disruptor. That means it can have negative effects upon the human (and other animals) hormonal system.

A new variant with the label “PLA” is biodegradable and can be used as compost.

In our next post – Plastic And Its Potential Damage To Our Health – we will go into more detail about some of the health hazards of plastic.

In the meantime, We hope this information helps you to decide which plastics you choose to use and which you decide to resist. However, given all can be harmful and we are constantly learning about new health issues with plastics, it’s a good idea to avoid contact with food and water whenever possible. For example, try using a stainless steel or glass refillable water container and take it with you. This will not leach toxins into your body and reduce the amount of toxic plastic pollution in the environment.

fresh” veggies. But how much healthier might it be without the plastic contaminants?

Plastic, even if recyclable, still has chemicals which pollute our environment. As citizens of earth, let’s try to avoid using these harmful products and do our bit to help keep our environment safe.


Dr. Jason Barritt, B.Sc. (Hons) DC


Reetika Vadgaonkar, B.Sc Physics


1. L Sax Environ Health Perspect. 2010 Apr; 118(4): 445–448. Online at https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2854718/ (Accessed 11 Sept. 2017)

2. https://www.ncbi.nlm.nih.gov/pubmed/17707454 [Accessed 11 September 2017].

3. https://www.ncbi.nlm.nih.gov/pubmed/16470261 [Accessed 11 September 2017].

4. https://www.ncbi.nlm.nih.gov/pubmed/28363141 Accessed 11 September 2017].

5. We used this site throughout our article: “www.learn.eartheasy.com,” eartheasy, 2 May 2012. [Online]. Available: http://learn.eartheasy.com/2012/05/plastics-by-the-numbers/. [Accessed 12 June 2017].

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