We all want to get it right with plastics recycling, but with varying recycling rules and discouraging sounding statistics about recycling, it can be a bit confusing. Additionally, there isn’t just one type of plastic; in fact, there are 7 main types of plastics. Despite the confusion, properly sorting and recycling plastics is a key part of the University of Michigan’s waste goals and one that students and community members can actively contribute to!
Today we’ll break down the different types of plastics, plastic shapes, and recycling processes to identify plastics and where they go in the recycling process. At the end of this blog, you can see information about which plastics are accepted on the University of Michigan Ann Arbor campus, and which plastics are accepted by the City of Ann Arbor (remember they are different!).
How Recycling Works
Materials Recovery Facilities, or MRFs, are responsible for sorting plastics and other recyclables received from various businesses, institutions, local governments, and more. Each center has their own machines which determine the types of plastics they have capability to sort. If a plastic that machines cannot properly sort enters the waste stream, it can jam or damage the machines and halt sorting. For example, if a plastic bag mistakenly is put into the recycling stream, it could get caught in the gears of the sorting machine and cause it to jam. Additionally, plastics smaller than your fist are too small to be properly identified and sorted by machines. If the recycling stream is contaminated, it will severely hinder the recycling process, or cause that batch to be diverted to the landfill.
That is why sorting plastics and recycling correctly is so important for successful recycling. For each city, university, or any other institution, the materials accepted for recycling depends on the sorting capabilities of their recycling facility where the materials are sent.
For the University of Michigan, the recycling is sent to the Western Washington Recycling Authority in Chelsea, MI, where the plastics are sorted and sent to their respective centers to be recycled. Through this center, the University is able to accept types #1-2 and #4-7.
Numbers and Shapes
Plastics are assigned different numbers based on their type. Below is a breakdown of those categories and what to look for when recycling!
Every plastic product is stamped with a Resin Identification Code (RIC), introduced in 1988 by the plastics industry. The number inside the recycling arrows identifies the type of resin, but it does NOT mean the item is actually recyclable. Remember recyclability depends entirely on the facility.
Type 1: Polyethylene Terephthalate (PET / PETE)
Clear, strong, and lightweight. One of the most widely recycled plastics. Safe for single use — avoid reusing, as bacteria can accumulate in scratches.
Type 2: High-Density Polyethylene (HDPE)
Rigid, tough, and resistant to chemicals. One of the safest and most recyclable plastics — low risk of leaching, even when used repeatedly.
Type 3: Polyvinyl Chloride (PVC / Vinyl)
Durable and versatile but contains chlorine and often phthalates, which can harm human health. Difficult to recycle and can release toxic chemicals when burned. Avoid for food contact.
Type 4: Low-Density Polyethylene (LDPE)
Flexible and film-like. Considered relatively safe — low risk of leaching. Increasingly recyclable via store drop-off programs rather than curbside.
Type 5: Polypropylene (PP)
Heat-resistant and tough. Safe for food contact and microwave use. Recycling availability is growing — often accepted for yogurt tubs and containers.
Type 6: Polystyrene (PS / Styrofoam)
Lightweight but brittle and very hard to recycle economically. Styrofoam (expanded PS) is particularly problematic — it breaks into microplastics easily which can harm ecosystems and health.
Type 7: Other / Miscellaneous (OTHER (PC, ABS, Nylon…))
A catch-all for everything else — polycarbonate (PC), ABS, nylon, bioplastics, and multi-layer materials. Highly variable in safety and recyclability. Some contain BPA.
Why Shapes Matter More
Although plastic type is important, the shape of the plastic usually matters more due to sorting and contamination issues. In recycling facilities, plastics are frequently sorted by automated systems that identify by shape. This process is ideal for 3D shapes like bottles and containers. 2D shapes, or flexible plastics, like plastic wrappers and bags, are difficult to sort and often can jam the machines. Plastic lids, like yogurt lids, are too flat to be properly sorted and are often mis-sorted with paper and other flat recyclables.
What Plastics are Accepted on Ann Arbor campus?
On the University of Michigan Ann Arbor campus, plastic types #1-2 and #4-7 are accepted. This includes materials such as bottles, tubs, cups, containers, and bulky plastics. Plastic film, items smaller than a fist, and flat lids, however, are not accepted in building recycling bins on campus.
After the plastics are sorted at the Western Washtenaw Recycling Authority, the different types are sent to facilities to be processed and made into new materials. Clean Tech in Dundee, MI processes types #1 and #2 into pellets for bottles and synthetic clothing, Mel Tech Plastic in Ontario, CA processes rigid plastics into pellets for plastic bins and totes, and Recycling Revolution in Boca Raton takes types #4-7 to be resold.
Recycling Off-Campus
Public and residential recycling outside of the University campus is managed by the City of Ann Arbor. It’s important to note that the City of Ann Arbor’s recycling rules differ from the university. The Recycle Ann Arbor Materials Recovery Facility accepts types #1 and 2 plastic water bottles, jars, and jugs, as well as #5 plastic tubs. Be sure to check city guidelines for any off-campus recycling.
Conclusion
“Is recycling plastics worth it?” is a question many people ask, since a popularized statistic states that only 5-9% of plastics in the U.S. are recycled. However, this is misleading. The figure refers to the total amount of plastic produced, rather than the much smaller percentage of recyclable material that is actually binned and repurposed. The University of Michigan is confident that ACCEPTED PLASTICS which are properly recycled in our recycling program and sent to the Western Washtenaw Recycling Authority are actually recycled!
To learn more about what can be recycled on campus, take a look at the Where to Throw search tool.
Source: https://ocs.umich.edu/wp-content/uploads/2025/12/Plastics-Recycling-Fact-Sheet.pdf
Anna is a Waste Reduction and Engagement Intern for the Office of Campus Sustainability and a Junior in the Bachelor of Business Administration program at the Ross School of Business.