Polyethylene is the most widely produced commodity plastic and it is primarily used for packaging. Some common forms of polyethylene are:
LDPE is a flexible material that is used in food storage bags, trash and grocery bags, toys, and housewares. The plastic recycling code of LDPE is #4.1
HDPE has high strength and moderate stiffness. It has a higher melting point than LDPE and can be sterilized. It is used in bottles for milk and household cleaners, food storage bags, grocery bags, appliance housing and toys. The plastic recycling code of HDPE is #2.2
Is Polyethylene Safe?
Polyethylene is considered one of the safest plastics.
According to its Safety Data Sheet, polyethylene has not been found to be carcinogenic by several safety organizations including the International Agency for Research on Cancer (IARC) and the Occupational Safety and Health Administration (OSHA).
Not all polyethylene, however, is created equal. Plastics are often made with fillers, plasticizers, and additives to enhance their functionality.3 A single plastic product can contain dozens of added chemicals. Polyethylene is less likely than many other plastics to contain fillers, plasticizers and additives but they may still be present. Unfortunately, without better disclosure from manufactures about the content of specific plastic materials we can only speak about toxicity and safety in general terms.
Does Polyethylene Offgas?
Polyethylene does offgas but generally at a much lower rate than more toxic plastics such as PVC and polystyrene.4
Does Polyethylene Leach into Food and Drink?
While polyethylene is relatively stable, and it is generally considered a safer plastic for food and drink, it has also been shown to leach plastic additives. In one study, pure polyethylene resin did not leach any endocrine disrupting chemicals but common food containers made with polyethylene did leach.5 Leaching from plastic food containers is increased with heat, duration of contact, and acidity of the food or drink. So, consider how the item is being used and how you will be exposed to it. For example, a food storage bad made of polyethylene that is used to carry a snack of pretzels is less likely to leach than the same bag used to store hot tomato soup.
Avoiding any plastic is ideal because it not only poses risk to human health but it is harmful to the environment. But, if you must use products made with polyethylene, the risk of exposure is probably low.
1The Editors of Encyclopaedia Britannica. “Polyethylene.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 15 Nov. 2019, www.britannica.com/science/polyethylene.
2 The Editors of Encyclopaedia Britannica. “Polyethylene.” Encyclopædia Britannica, Encyclopædia Britannica, Inc., 15 Nov. 2019, www.britannica.com/science/polyethylen
3John N. Hahladakis, Costas A. Velis, Roland Weber, Eleni Iacovidou, Phil Purnell. An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. Journal of Hazardous Materials. 2018; volume 344; pages 179-199. License.
4Even M, Girard M, Rich A, Hutzler C and Luch A (2019) Emissions of VOCs From Polymer-Based Consumer Products: From Emission Data of Real Samples to the Assessment of Inhalation Exposure. Front. Public Health 7:202. doi: 10.3389/fpubh.2019.00202
5John N. Hahladakis, Costas A. Velis, Roland Weber, Eleni Iacovidou, Phil Purnell. An overview of chemical additives present in plastics: Migration, release, fate and environmental impact during their use, disposal and recycling. Journal of Hazardous Materials. 2018; volume 344; pages 179-199. License.