Have you ever wondered what the numbers, or recycling symbols, mean at the bottom of plastic bottles and containers? Did you know that, while the use of all plastics should be limited if at all possible, some are safer than others? It’s time to learn a little bit about the various plastics you use and drink/eat from every single day, and what impact they have not only on you, but also the environment.

Every plastic container or bottle has a recycling symbol. The symbol is a number, ranging from 1 to 7, within a triangle. While you may think nothing of these symbols, they can actually offer a great deal of information regarding the toxic chemicals used in the plastic, how likely the plastic is to leach, how bio-degradable the plastic is, and ultimately the safety of the plastic.

Here is some information on the various recycling symbols and numbers:

The Recycling Symbols

Plastic #1 – PETE or PET (Polyethylene Terephthalate)

• Characteristics: Picked up by most curbside recycling programs, plastic #1 is usually clear and used to make soda and water bottles.
• Sustainability: PET is 100% recyclable, and the recycling process for PET plastics consumes 84% less energy than making new PET plastics.
• Health and Safety: While PET is considered safe for food and beverage storage, like any other container, it can harbor bacteria if not cleaned properly. PET also does not contain BPA (bisphenol A), a chemical that has raised health concerns and is found in certain plastics.
• Usage: It’s found mostly in soda bottles, water bottles, beer bottles, salad dressing containers, mouthwash bottles, and peanut butter containers. Beyond bottles and containers, PET is also used in the production of films, engineering resins, and monofilament.
• Repurposing: Plastic #1 is recycled into tote bags, furniture, carpet, paneling, fiber, and polar fleece.
• Chemical Resistance: PET has excellent chemical resistance to organic materials and water, which is why it’s commonly used for packaging products that have a longer shelf life.
• Lightweight: PET bottles and containers are lightweight, which reduces the amount of energy required for transportation compared to glass containers.
• Carbon Footprint: The production of PET generates fewer greenhouse gas emissions compared to other plastics and even some other packaging materials like glass.
• UV Resistance: PET can be treated to be resistant to UV light, which helps protect products from the harmful effects of the sun’s rays.
• Popularity: PET is the most recycled plastic worldwide, thanks to its widespread use and the ease of recycling.
• Economic Impact: The PET recycling industry has created thousands of jobs, contributing significantly to the economy in many regions.
• Innovation: Researchers are continuously working on bio-based PET, which uses renewable plant materials to produce PET, further reducing its environmental impact.

Plastic #2 – HDPE (High Density Polyethylene)

• Characteristics: Plastic #2 is typically opaque and picked up by most curbside recycling programs.
• Health and Safety: This plastic is one of the 3 plastics considered to be safe, and has a lower risk of leaching. HDPE does not contain BPA, phthalates, heavy metals, or allergens, making it a safe choice for food storage.
• Common Items: It’s found mostly in milk jugs, household cleaner containers, juice bottles, shampoo bottles, cereal box liners, detergent bottles, motor oil bottles, yogurt tubs, and butter tubs. Milk jugs, detergent bottles, juice bottles, butter tubs, and toiletries bottles are made of this.
• Repurposing: Plastic #2 is recycled into pens, recycling containers, picnic tables, lumber, benches, fencing, and detergent bottles, to name a few.
• Durability: HDPE is known for its strength-to-density ratio, making it resistant to impact, mold, rot, and insects. This is why it’s often used for outdoor furniture and playground equipment.
• Chemical Resistance: HDPE has excellent resistance to many chemicals, making it the material of choice for many household containers that store detergents, bleach, and other household chemicals.
• Temperature Tolerance: HDPE can withstand higher temperatures, which is why it’s used for containers that might be exposed to sunlight or heat.
• UV Resistance: While HDPE is resistant to many things, prolonged exposure to UV can degrade the material. However, it can be treated to be more UV resistant.
• Environmental Impact: HDPE emits no harmful fumes into the environment during its production or during its lifecycle, making it an environmentally friendly choice.
• Versatility: Beyond the commonly known uses, HDPE is also used in the production of fireworks, snowboards, and even in some bulletproof vests applications.
• Weldability: HDPE can be welded, which is a process that allows pieces of HDPE to be fused together. This property is utilized in various industrial applications.
• Recycling Rate: HDPE bottles have one of the highest recycling rates among plastics. In many countries, over 30% of HDPE bottles are recycled.
• Economic Impact: The HDPE industry supports thousands of jobs across the globe, from manufacturing to recycling.

Plastic #3 – V or PVC (Polyvinyl Chloride)

• Characteristics: PVC can be either transparent or opaque, but is slightly cloudy or milky in appearance when in its natural state. While naturally white or pale yellow, PVC can be colored into virtually any shade. It’s typically marked with the recycling symbol “3” inside the triangular arrows, with the letter “V” underneath.
• Recycling Acceptance: Plastic #3 is less commonly accepted by curbside recycling programs.
• Common Items: Plastic #3 is used to make shampoo bottles, clear food packaging, cooking oil bottles, medical equipment, piping, and windows.
• Health and Safety: These plastics used to, and still may, contain phthalates, which are linked to numerous health issues ranging from developmental problems to miscarriages. DEHA (Di(2-ethylhexyl) adipate) is sometimes used as a plasticizer in PVC, and has been associated with health risks in some studies.
• Recycling Outcomes: This plastic is recycled into paneling, flooring, speed bumps, decks, and roadway gutters.
• History: PVC was first synthesized in 1872 by German chemist Eugen Baumann. However, it wasn’t until the early 20th century that methods to process and use PVC in commercial applications were developed.
• Versatility: PVC is one of the most versatile plastics. It can be made soft and flexible or hard and rigid, depending on the additives used during its production.
• Chlorine Content: PVC is unique among plastics because it contains chlorine, making up about 57% of its mass. This chlorine is derived from industrial salt.
• Fire Resistance: Due to its chlorine content, PVC is naturally fire resistant and is often used in applications where fire resistance is important, such as in building materials.
• Phthalate Controversy: There has been significant debate over the use of phthalates as plasticizers in PVC, especially in toys and other children’s products. Many countries have regulations limiting or banning the use of certain phthalates in these applications.
• Medical Uses: PVC is used in a variety of medical applications, including blood bags and intravenous (IV) tubing. However, there’s ongoing research to find alternatives due to concerns about plasticizers leaching into the bloodstream.
• Environmental Concerns: When improperly disposed of, PVC can release dioxins, which are environmental pollutants, especially when burned. This has led to calls for more responsible disposal and recycling methods for PVC products.
• PVC in Construction: PVC is widely used in the construction industry. From window frames to roofing materials and piping, its durability and resistance to environmental elements make it a popular choice.
• Vinyl Records: The “vinyl” in vinyl records refers to PVC. These records are made from a particular formulation of PVC that allows for the grooves of the record to be pressed into them.

Plastic #4 – LDPE (Low Density Polyethylene)

• Characteristics: While LDPE can be made transparent, it’s often not crystal clear. In its natural state, LDPE is typically milky-white or clear. However, it can be colored during the manufacturing process to produce products in various hues.
• Common Items: Low density polyethylene is most found in squeezable bottles, shopping bags, clothing, carpet, frozen food, bread bags, and some food wraps.
• Recycling Acceptance: Curbside recycling programs haven’t been known to pick up this plastic, but more are starting to accept it. Many grocery stores collect LDPE bags for recycling.
• Health and Safety: Plastic #4 rests among the recycling symbols generally considered to be safe for food contact and other common uses. LDPE doesn’t contain BPA, and there’s no evidence suggesting it leaches harmful chemicals into foods or drinks.
• Recycling Outcomes: This plastic is recycled into compost bins, paneling, trash can liners and cans, floor tiles, and shipping envelopes.
• Carbon Footprint: The production of LDPE typically consumes less energy compared to some other plastics, resulting in a lower carbon footprint.
• Biodegradability and Environmental Concerns: LDPE is not biodegradable and can persist in the environment for hundreds of years. However, it’s less likely to leach chemicals into the soil or water compared to some other plastics. Due to environmental concerns, there’s a push towards finding biodegradable or more sustainable alternatives to LDPE, especially for single-use items like shopping bags.
• Flexibility: LDPE is known for its flexibility, which is why it’s used for products like squeezable bottles and plastic bags.
• Chemical Resistance: LDPE has a strong resistance to acids, bases, and vegetable oils, making it useful for packaging various products.
• Low Melting Point: LDPE has a lower melting point compared to other plastics, which is why it’s not recommended for boiling or hot liquid storage.

Plastic #5 – PP (Polypropylene)

• Characteristics: In its natural state, Plastic #5 is semi-transparent with a milky-white or clear color, but not as clearly as some other plastics. It can be dyed into any color.
• Recycling Acceptance: Polypropylene is increasingly being accepted by curbside recycling programs.
• Health and Safety: Polypropylene is generally considered one of the safer plastics for food storage and other common uses. It doesn’t contain BPA, and there’s no evidence suggesting it leaches harmful chemicals into foods or drinks.
• Common Items: Plastic #5 is typically found in yogurt containers, ketchup bottles, syrup bottles, and medicine bottles. It’s also found in automotive parts, textiles (non-woven PP is used in diapers and sanitary products), and even in the banknotes of some countries due to its durability.
• Recycling Outcomes: Plastic #5 can be used to make a range of products including brooms, auto battery cases, bins, pallets, signal lights, ice scrapers, and bicycle racks.
• Heat Resistance: PP has a high melting point, making it suitable for microwave-safe containers. It doesn’t warp in high temperatures as some other plastics might.
• Chemical Resistance: Polypropylene is resistant to many chemicals, including acids and bases, which is why it’s commonly used for containers that store a variety of products.
• Elasticity & Toughness: Despite being lightweight, PP has a good balance of toughness and elasticity, which is why it’s used in items like living hinges (e.g., flip-top bottle caps).
• Moisture Barrier: PP acts as a good barrier against moisture, making it a popular choice for packaging that needs to keep moisture out or retain moisture within.
• Recycling Rate: While PP is recyclable, its recycling rate has historically been lower than PETE or HDPE. Efforts are ongoing to improve its recycling rates.
• Non-reactive: Due to its chemical resistance, PP doesn’t easily react with or leach chemicals into the contents it holds, making it a preferred choice for food and medical storage.
• Lightweight: The lightweight nature of PP reduces transportation costs and emissions when compared to heavier packaging materials.
• End-of-Life: Research is ongoing to develop better methods for the degradation and recycling of PP to reduce its environmental impact.

Plastic #6 – PS (Polystyrene)

• Solid Polystyrene:
  • In its solid form, polystyrene can be transparent, translucent, or opaque, but can be dyed into any color. Typically smooth and can have a shiny or matte finish.
  • Examples: CD cases, disposable cutlery, and some plastic cups.
• Expanded Polystyrene (EPS):
  • What you know as “Styrofoam.” It’s white and has a distinctive “beady” appearance, made up of many tiny beads fused together.
  • Examples: Packaging materials, coffee cups, meat trays, and egg cartons.
• Extruded Polystyrene Foam (XPS):
  • Often blue or pink, this is a denser, smoother type of foam compared to EPS. It’s Smooth and is less likely to crumble than EPS.
  • Examples: Insulation boards and sheets.
• Identification: Commonly known as polystyrene, this plastic is sometimes referred to by its popular brand name, Styrofoam, especially when in its expanded form.
• Environmental Concerns: Polystyrene, particularly in its expanded form, is challenging to recycle. Its lightweight nature and the economics of recycling make it less attractive for many recycling programs. As a result, it often ends up in landfills, contributing to environmental concerns.
• Recycling Acceptance: Solid polystyrene is occasionally accepted in municipal recycling programs, but it’s less common. Expanded polystyrene (EPS) is rarely accepted in curbside recycling programs due to its lightweight nature and the economic challenges of recycling it. Some specialized drop-off locations may accept it.
• Health and Safety: There are concerns about polystyrene potentially leaching styrene, especially when in contact with hot or acidic foods. Styrene is considered a possible human carcinogen. It’s advisable to avoid microwaving food in polystyrene containers or using them for hot liquids.
• Common Items: Polystyrene is versatile and is used in a range of products, including compact disc cases, egg cartons, meat trays, and disposable plates and cups.
• Recycling Outcomes: Solid polystyrene can be recycled into items like office accessories, insulation, and other plastic goods. Expanded polystyrene, when recycled, can be turned into products like egg cartons, vents, foam packing, insulation, crown molding, picture frames, and park benches. However, the actual rate of recycling is low due to the challenges associated with its recycling process.

Plastic #7 – Other, Miscellaneous

• Identification: All of the plastic resins that don’t fit into the other categories are placed in the number 7 category. It’s a mix bag of plastics that can include polycarbonate, which may contain bisphenol-A (BPA).
• Common Items: Plastic #7 can be found in a variety of products, including sunglasses, iPod cases, computer cases, nylon, 3- and 5-gallon water bottles, and bulletproof materials.
• Recycling Outcomes: Plastic #7 is less commonly recycled than some other types, but when it is, it can be turned into products like plastic lumber.

The Bottom Line: Which Recycling Numbers to Avoid, Which are ‘Safest’

Plastics #3 (PVC) and #6 (Polystyrene) have raised health concerns, especially when used for food and drink. Plastic #7 is a mixed category, and some plastics under this category, like those containing BPA, have raised health concerns. However, not all #7 plastics are harmful.

PET (Plastic #1) is generally considered safe for single use, but there are concerns about repeated use due to potential leaching of chemicals.

HDPE (Plastic #2), LDPE (Plastic #4), and PP (Plastic #5) are generally considered safer plastics for food and drink consumption.

This article was originally published in 2013 but has since been completely updated.

Additional Sources:

NYC.gov

EPA.gov