Plastic #4 refers to  (LDPE).  It is known for its flexibility, transparency, and durability.

Some things made of LDPE

• Plastic bags
• Bubble wrap
• Food storage containers
• Plastic wraps (cling film)
• Shrink wrap (eg wrap on drink can multi-packs)
• Squeezable bottles (e.g. honey or ketchup)
• Trash can liners
• Plastic sheets for covers and tarps
• Shrink wrap for packaging
• Wire and cable insulation
• Toy balls and pool toys
• Garden hose and irrigation piping

Although LDPE is technically recyclable, it is considered a "lower value" plastic and has a very low recycling rate. Meaning, the market demand for LDPE waste is very low, so even though it is accepted in blue bins, it is unlikely to be recycled.

Many municipalities around the world have stopped collecting LDPE due to to the difficulty in finding recycling companies to take it.

Why we say: Just Bin It

Generally speaking, we recommend you throw this plastic away instead of recycling it, as the vast majority will be incinerated, overloading the recycling system.

When you put LDPE in the blue bin,  it takes "the long route” to the incinerator (trucked to the sorting plant, then later trucked to the incinerator). This puts pressure on the recycling system making it less efficient.

We believe that the carbon cost of having 95-98% of LDPE end up incinerated vs <2% of LDPE actually being recycled does not make it worth it. The transportation and sorting labour involved very likely uses more carbon that it saves and so it is net negative for climate change.

Saying that, this is strictly our opinion and we do not have the research to back up this assumption at this time.

Our estimate of <2% recycling rate for post consumer LDPE comes from the fact that the overall plastic recycling rate is 4-6% of which the vast majority (based on market reports) comes from PET and HDPE. 

Industry vs Household Consumers

Also understand that LDPE waste coming from businesses / industry may be more feasible to recycle because of the volume and purity of the material. 

Post-consumer waste (the stuff generated by individuals) is much harder to deal with because it requires a lot of sorting and it is sometimes hard to tell one plastic from another. So the resulting bailed plastic waste is very low quality.

The composition of the bales is also highly inconsistent, with high variability over time and by source, making it difficult to use them in downstream processing. - McKinsey  2022

Our suggestion to “bin it” applies to post-consumer waste.