What plastic pollutes the ocean the most? Top culprits and who makes them

Every year, over 11 million tons of plastic enter the oceans. That’s enough to cover every coastline on Earth with five full bags of trash. But not all plastic is the same. Some types show up in huge amounts, while others linger for decades, breaking into tiny pieces that poison marine life. If you’re asking what plastic pollutes the ocean the most, the answer isn’t just about the material-it’s about who makes it, how it’s used, and why it never goes away.

Polyethylene is the biggest offender

The most common plastic in ocean waste is polyethylene. It makes up nearly 70% of all plastic debris found in marine environments. You’ll find it in plastic bags, food wrappers, bottles, and containers. Two versions dominate: HDPE (high-density polyethylene) and LDPE (low-density polyethylene). HDPE is used for milk jugs and detergent bottles. LDPE is the thin, flexible plastic you get from grocery bags and snack packaging.

Why does it dominate? Because it’s cheap, easy to produce, and designed for one-time use. Companies like ExxonMobil, Dow, and SABIC produce billions of tons of polyethylene every year. Most of it ends up in packaging that’s used for seconds and discarded within minutes. In 2023, global plastic production hit 413 million tons. Over 30% of that was polyethylene. Less than 10% was recycled.

Polypropylene is right behind

The second most common plastic in ocean pollution is polypropylene. You see it in bottle caps, straws, takeout containers, and yogurt tubs. It’s lightweight, heat-resistant, and durable-perfect for food service. But that durability is its downfall. A single plastic straw made of polypropylene can float for years before breaking down into microplastics.

Major producers like LyondellBasell and Chevron Phillips Chemical churn out over 80 million tons of polypropylene annually. Much of it goes into disposable food packaging. In beach cleanups across the Mediterranean, Southeast Asia, and the Caribbean, polypropylene items like bottle caps and straws consistently rank in the top five most collected items. In 2024, researchers found polypropylene in 82% of seabird stomachs sampled in the North Pacific.

Polystyrene: The invisible threat

Polystyrene-especially expanded polystyrene (EPS), commonly known as Styrofoam-is one of the most dangerous plastics for marine life. It breaks apart easily into tiny beads that look like plankton. Fish, turtles, and seabirds mistake them for food. Once ingested, these particles block digestive tracts and leach toxic chemicals like styrene.

Companies like Dow and INEOS produce polystyrene for packaging, disposable cups, and insulation. In 2022, a study in the journal Environmental Science & Technology found that polystyrene was the most abundant plastic fragment in deep-sea sediment samples from the Pacific Ocean. Unlike polyethylene, which can be recycled in theory, polystyrene is rarely collected. Its low value and high volume make it economically unviable to recycle. So it stays in the environment for over 500 years.

Where does it come from? The manufacturers behind the pollution

The plastic polluting the ocean isn’t just the result of careless consumers. It’s the product of a global manufacturing system built on overproduction and planned obsolescence. Just 20 companies are responsible for more than half of all single-use plastic waste worldwide. These include ExxonMobil, Dow, SABIC, LyondellBasell, and Shell.

These companies don’t just make plastic-they design the packaging that makes it unavoidable. For example, Coca-Cola alone produces over 3 million tons of plastic packaging annually. That’s more than the total plastic waste produced by 140 low-income countries combined. Yet, Coca-Cola and PepsiCo continue to push for recycling as the solution, even though less than 9% of all plastic ever made has been recycled.

Manufacturers know this. They’ve spent decades funding public campaigns that blame individuals for plastic waste. But the truth is simple: if you don’t make it, it won’t pollute. The plastic industry has known since the 1970s that recycling rates would never be high enough to handle the volume they were producing. They kept growing anyway.

Microplastics: The silent epidemic

It’s not just big bottles and bags. The real crisis is hidden in plain sight: microplastics. These are plastic fragments smaller than 5 millimeters. They come from broken-down bottles, synthetic clothing fibers, and even cosmetics. But the biggest source? Tire wear and synthetic textiles.

Every time you wash a polyester shirt, it releases 700,000 microfibers into the water. These fibers travel through sewage systems and end up in rivers and oceans. In the North Atlantic, researchers found microplastics in 100% of surface water samples. In the Arctic, they’ve been found in sea ice that’s over 100 years old.

Manufacturers of synthetic fabrics-like DuPont, Lenzing, and Toray-produce over 60 million tons of polyester annually. Most of it is used in fast fashion. A single pair of synthetic running shoes can shed 10,000 microplastic particles in just one run. And no wastewater treatment plant can catch them all.

Why recycling doesn’t fix this

You’ve heard the message: recycle more. But the system was designed to fail. Plastic recycling is not a solution-it’s a distraction. Most plastic isn’t recyclable. Of the 7.8 billion tons of plastic ever produced, only 9% has been recycled. The rest was burned, dumped, or leaked into nature.

Even the plastics that can be recycled often aren’t. Polyethylene bottles are collected, but they’re downcycled into lower-quality products like park benches or carpet fibers. Eventually, they become waste again. And polypropylene? Most recycling centers won’t take it. Polystyrene? Almost never.

Manufacturers know this. They’ve lobbied governments to avoid plastic taxes, pushed for voluntary industry pledges, and funded misleading advertising that makes people believe recycling works. The truth? Recycling plastic is like trying to mop up a flood with a teaspoon.

What actually works

Real solutions focus on stopping plastic at the source. Countries that banned single-use plastics-like Canada, the EU, and Kenya-have seen up to 70% reductions in plastic waste in rivers and coastlines. The key? Eliminate the most common items: bags, straws, cutlery, food containers, and bottles.

Companies that are making progress? Those shifting to reusable systems. Loop, a global initiative backed by Unilever and Nestlé, delivers products in returnable containers. In Bristol, local shops now offer refill stations for detergents, shampoos, and oils. Customers bring their own jars. No plastic needed.

But real change requires holding manufacturers accountable. The UN is negotiating a global treaty to end plastic pollution by 2024. It would force companies to design products for reuse, reduce production of single-use items, and pay for cleanup. So far, over 170 countries support it. The U.S. and China are still negotiating.

What you can do

Individual action alone won’t solve this. But your choices can pressure companies and shape policy.

• Avoid products wrapped in plastic. Choose loose produce, glass bottles, or metal containers.
• Support brands that use refill systems or packaging-free delivery.
• Don’t buy fast fashion made from polyester. Look for cotton, linen, or wool.
• Write to companies that use excessive plastic. Ask them to reduce it. Public pressure works-PepsiCo cut 12% of its plastic use after consumer campaigns.
• Vote for leaders who support plastic production caps and extended producer responsibility laws.

The plastic in the ocean didn’t appear by accident. It was made. It was sold. It was thrown away. And it will keep coming-unless we stop the machines that produce it.