What About Those Fumes?

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Every synthetic substance out-gasses, including plastic. Think about that new-car smell, which is mostly plastic. Or recycled plastic sport shoes. Or synthetic leather (they don’t call it “pleather” for nothing.) So lacing up your new sneakers, driving your new wheels to work, or relaxing after work on your new plastic couch, you’re breathing what might be a relatively toxic substance. 

How toxic plastic is depends on what type of plastic it is and what additives are present in it. Items that will be collected for our Precious Plastic project will be made of only the safest plastic types. (See the chart below.)

For the safest plastic types, melting is safe providing reasonable care is taken not to overheat the plastic. Reasonable care also includes wearing heat-resistant protective clothing and installing proper ventilation. Ventilation is advised since the melting and extrusion processes can produce dust, vapor or fumes from additives. Some people who work with Precious Plastic equipment also recommend wearing a respirator. This may be because most of these people work with riskier plastics, or it may be out of an excess of concern about safety. Your plastic up-cycling team also recommends wearing a respirator, since it is important to both be safe and feel safe.  

Plastic Type Type
Items Melting
Temp (F)
Safety Assessment Material Safety Data Sheet Info
Polyethylene Terephthalate (PET or PETE) 1 Soda bottles
Water bottles
Salad dressing bottles
Medicine jars
Peanut butter jars
Jelly Jars
Bean bags
Tote bags
Clothing fiberfill
260° – 280° Safe “No known adverse effect on human health.” Possible irritation of eyes or skin.
High-Density Polyethylene (HDPE) 2 Milk jugs
Juice containers
Grocery bags
Trash bags
Motor oil containers
Shampoo/conditioner bottles
Soap bottles
Detergent containers
Bleach containers
210° – 270° Safe “Not hazardous.” Possible irritation of eyes or nose.
Polyvinyl Chloride (PVC) 3 Some tote bags
Plumbing pipes
Grocery bags
Cling films
Window frames
Sewage pipes
170° – 210° Very risky and will never be used
Low Density Polyethylene (LDPE) 4 Cling wrap
Sandwich bags
Condiment squeeze bottles
Grocery bags
Frozen food bags
Flexible container lids
180° – 240° Safe “Conditions to avoid: None Known…. Medical Restrictions: None Known.” Dust respirator recommended.
Polypropylene (PP) 5 Plastic diapers
Margarine tubs
Yogurt containers
Prescription bottles
Stadium cups
Bottle caps
Take-out containers
Disposable cups/plates
200° – 290° Safe “Not toxic, harmful, irritant or corrosive.” Possible irritation of eyes or nose.
Polystyrene (PS) (ABS) 6 Disposable coffee cups
Plastic food boxes
Plastic cutlery
Packing foam
Packing peanuts
170° – 290° Risky and will be carefully evaluated before use
Everything else (PC, PA, Nylon, etc.) 7 Plastic CDs and DVDs
Baby bottles
multi-gallon water bottles
Medical storage containers
Exterior lighting fixtures
May be very risky and will never be used


Zhigui H. et al (5 January 2015) “Pollution characteristics and health risk assessment of volatile organic compounds emitted from different plastic solid waste recycling workshops.” Guangdong University of Technology Environmental Health and Pollution Control Institute. 7 September 2019 from http://iehpc.gdut.edu.cn/2015-7.pdf 

Hahladakis, J. et al (15 February 2018)An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling.” Journal of Hazardous Materials, Vol 344, pages 179-199. 8 September 2019 from https://www.sciencedirect.com/science/article/pii/S030438941730763X

Sparkman, O. et al (2011) “Hydrocarbons.” Gas Chromatography and Mass Spectrometry (Second Edition). 7 September 2019 from https://www.sciencedirect.com/topics/chemical-engineering/hydrocarbon

“Does melting PET plastic bottles release harmful fumes that endanger human health and the environment?” (28 December 2017) Quora. 8 September 2019 from https://www.quora.com/Does-melting-PET-plastic-bottles-release-harmful-fumes-that-endanger-human-health-and-the-environment