The Plastic World

There is so much misinformation about plastic that it can be frustrating and even infuriating for parents. One thing for sure, you should never heat anything in a plastic container, NEVER. Extreme temperatures can break down plastic, even freezing. Once plastic has been heated or frozen, it’s chemical composition can change and make it unstable. This is why heated plastics can leach out chemicals into your food, so take them out of their original packaging and place them in a glass container to microwave or cook or defrost.

There is a great deal of talk about the recyclable plastics. #1, #2, #3, #4, #5, #6, and #7. None of which are good for the environment as they all end up in our ocean and food supply, but if you must use plastic here are the facts on the structure, where they are used, what you should avoid and why. 


recycle-98854_640Polyethylene Terephthalate


Plastic #1, aka PET or PETEa form of polyester and a very common thermoplastic polymer resin.

Where is Plastic #1 used?

Here are some packaging and products where you will find it:

  • Soft drink bottles
  • Cosmetics
  • Single serve water bottles
  • Beer
  • Juice
  • Salad dressings
  • Oil
  • Peanut butter
  • Ketchup
  • Sleeping bags
  • Polyester clothing
  • Carpeting

What are some health Issues? 

The concern is that PET is prone to many types of degradation:

According to The International Agency for Research on Cancer (IARC), acetaldehyde is listed as a Group 1 carcinogen, and when plastic #1 is improperly manufactured or containers misused or mishandled, this substance can leach into the product creating an “off” taste in a product like water. Unfortunately, in other stronger tasting food and drinks, it will probably go undetected.

Antimony, a metalloid element, is used in the production of PET. This chemical can be found on the surface of the product in the form of a residue. It remains inside the product, as well, and is routinely leached out into the food and drinks. Any extreme heat such as boiling and microwaving will increase the amount leached out into the food or drink products. Water bottles studied by The Swiss Federal Office of Public Health concluded that levels in bottle water were a negligible health risk, although, concentrations found in fruit juice from the UK were found to contain levels well above the EU limits of 5µg/L

The Journal of Environmental Monitoring confirms the concentration found in water stored in PET bottles, but goes further to state that bottles may occasionally exceed these limits after less than a year of storage at room temperature. Because of this, more research is being requested on the possibility of endocrine disrupting chemicals leaching out of PET containers and contaminating products, specifically due to antimony.

“The contents of the PET bottle, and the temperature at which it is stored, both appear to influence the rate and magnitude of leaching. Endocrine disruptors other than phthalates, specifically antimony, may also contribute to the endocrine-disrupting effect of water from PET containers.”  

Leonard Sax of the Montgomery Center for Research in Child and Adolescent Development, Exton, Pennsylvania

recycle-98855_640High density polyethylene


Plastic #2 aka HDPE or PEHD is a polyethylene thermoplastic made from petroleum.

Where is Plastic #2 used?

  • Personal Care Products
  • Juice bottles
  • garbage bags
  • grocery bags
  • cleaning products
  • Milk
  • Food storage containers

What are some health Issues?

This plastic is considered a low or non hazard plastic, although, a study released in 2011 reported that most plastic products, including HDPE, released estrogenic chemicals. Chemicals with estrogenic activity (EA) can cause health issues in fetal and juvenile humans, especially at low doses, by altering the structure of the human cells. 

recycle-98856_640Polyvinyl chloride


Plastic #3 aka PVC is produced from the vinyl chloride monomer; phthalates are routinely used to make this structure more flexible.

Where is Plastic #3 fused?

  • deli and meat wrap
  • shrink-wrap
  • bags for bedding
  • tamper resistant lids
  • shower curtains
  • waterbeds
  • pool toys
  • inflatable structures
  • clothing
  • IV bags used in neo-natal intensive care
  • can be used to make artificial leather, floor coating, and polyurethane

What are some health Issues?

Di(2-ethylhexyl) phthlate (DEHP) is used widely in consumer products and can leach into blood or other similar lipid-containing solutions that come in contact with the plastic. It is associated with asthma in children. Two studies, one from Columbia University’s Mailman School of Public Health and the other from Jouni J.K. Jaakkola and  Trudy L. Knighthave shown adverse effects on airways and/or the immune system due to exposure of products containing DEHP.

EU has listed this chemical as one of the top 6 chemicals threatening human health. This has prompted organizations like Health Care Without Harm to call for the phase-out of PVC products throughout Europe.

recycle-98857_640Low-density polyethylene


Plastic #4 aka LDPE is a thermoplastic made from monomer ethylene. 

Where is Plastic #4 used?

  • opaque juice, milk, soup cartons are lined with the plastic coating
  • grocery bags
  • packaging material
  • snap-on lids
  • six-pack rings
  • playground slides
  • plastic wrap
  • squeezeable bottles like honey and mustard

What are some health Issues?

This plastic is considered very stable at room temperature, and can take high temperatures of 80°C (176°F)  for brief periods before breaking down, but still not advised to use as heating container for food or drinks.



Plastic #5 aka PP is a thermoplastic polymer.

Where is Plastic #5 used?

  • yogurt containers
  • butter and margarine
  • take out meals
  • deli foods
  • bottle caps
  • ketchup and syrup bottles
  • baby bottles
  • kitchen ware

What are some health Issues?

Plastic #5 is considered a safe plastic. It can resist many chemical solvents and is considered quite rugged. It can breakdown from UV radiation and exposure to heat, so microwaving and heating is not advised.



Plastic #6 aka PS and Styrofoam is a synthetic polymer made from styrene.

Where is Plastic #6 used?

  • coffee cups and lids
  • hinged take out containers
  • meat, poultry, fish trays
  • rigid food containers
  • baby and toddler car seats
  • CD and DVD cases
  • egg cartons
  • disposable utensils
  • packaging peanuts

What are some health Issues?

Polystyrene does not biodegrade for hundreds of years, it is highly flammable and usually contains flame retardants when used in an application where heat exposure may occur. The styrene monomers that make up polystyrene are readily released into food or liquids when exposed to heat. 

The Department of Health and Human Services (DHHS), National Toxicology Program (NTP) listed styrene as “reasonably anticipated to be a human carcinogen” in the Report on Carcinogens, Twelfth Edition, released on June 10, 2011. Other agencies like, The International Agency for Research on Cancer (IARC) and The FDA, have determined that styrene is a possible carcinogen and concentration of styrene in bottled drinking water should not exceed 0.1 mg/L. 

Some chronic effects from long-term exposure to styrene are central nervous system (CNS) dysfunction, headaches, fatigue, weakness, depression, minor effects on the kidney enzyme functions and blood(low platelet and hemoglobin values), to name a few.



Plastic #7 this plastic is the catch-all that describes “other” plastics that differ from the first six types. 

Where is Plastic#7 used?

  • large reusable water bottles (e.g. 3 & 5 gallon containers)
  • citrus juice bottles 
  • ketchup bottles
  • oven baking bags
  • custom packaging
  • food processor bowls and parts
  • blenders
  • household appliances

What are some health Issues?

The problem is finding out what the plastic is made out of, and with limited regulation on labeling, you may get something you don’t want. Bisphenol A (BPA) has been getting a great deal of attention for it’s health risks for pregnant women and children, but what few consumers realize is BPA has been substituted with BPS, a similar substance that has greater health risks than BPA and is not disclosed on the packaging. There has been an out-cry to rid baby products of these toxic substances, but this has not necessarily rid the plastics of the harmful endocrine inhibiting chemicals.

Some health risks of BPA & BPS are lower sperm count, hormonal changes, enlarged prostate glands, asthma, abnormalities in number of chromosomes in eggs, and pre-cancerous changes in the breast and prostate tissue(shown in study on mice). BPA suppresses the expression of a gene vital to nerve cell function and the development of the central nervous system, which could predispose humans to neurodevelopment disorders and autism. If that isn’t enough, BPA is also linked to obesity and insulin resistance.

Why limit plastic use?

Manufacturers often add different chemicals to plastics to give them the exact characteristics they’re looking for, like flexibility and strength and to reduce production cost. These chemicals include phthalates, bisphenol A (BPA), polybrominated diphenyl ethers (PBDE) and tetrabromobisphenol A (TBBPA) — all of which are known to alter hormone expression in nonhuman animals and humans.

In a study conducted by Chun Z. Yang and his colleagues, common-use stresses (boiling water, microwaving, and UV radiation) for products classified by resins HDPE, PP*, PET, PS, polylactic acid, and PC still resulted in leaching of chemicals into the products. “Almost all commercially available plastic products we sampled—independent of the type of resin, product, or retail source—leached chemicals having reliably detectable EA (estrogenic activity), including those advertised as BPA free. In some cases, BPA-free products released chemicals having more EA than did BPA-containing products.” the study concluded.

Although BPA [bisphenol A] is the most notorious chemical with estrogenic activity used in plastics, it is not the only one, nor does it have the highest biological effect,” a study co-author George D. Bittner, a neurobiologist at the University of Texas, Austin, told Chemical & Engineering News.

Some good news is the prospect of the use of clarified PP which was found to not leach additives that exhibit EA, even when stressed. What was even more interesting was the decreased cost to manufacture clarified PP, 0.08 less per pound to make molding bottles.  Why clarified PP is not commonly used for food and beverage containers is unclear, but increased pressure and public knowledge may shift the current trend away from endocrine inhibiting plastics to more stable ones. For now, #2, #4, and #5 in everyday applications are the safest. Just don’t use them to heat your food.