What Are Nurdles, and Why Do They End Up in the Ocean?

Almost every plastic object within reach of you right now began as a lentil-sized pellet. Bottles, packaging, car bumpers, toothbrush handles, toys: all started as small beads of polymer shipped to a factory, melted and pushed into a mould. The industry calls them resin pellets. Everyone else calls them nurdles.

An estimated 11.5 trillion of them enter the ocean each year. They are the second-largest source of primary microplastic pollution by weight, and uniquely among marine plastics, they arrive already at microplastic size, requiring no weathering or fragmentation to become a problem. Legally, they are also not hazardous, which is the most interesting thing about them and the reason the response has taken so long.

 

The Building Blocks of Everyday Plastic

 

A nurdle is typically between two and five millimeters across, usually cylindrical or lens-shaped, and most often white or translucent. It is produced at a petrochemical plant, where polymer is extruded and chopped into pellets precisely because pellets are easy to measure, pour, convey and melt. They are the standard form in which plastic is traded.

Global production runs to hundreds of millions of tonnes a year, and the pellets move in enormous volume between producers and the converters who turn them into finished goods. Those are usually different companies in different countries, which means the raw material of the plastics industry spends much of its life in transit.

That transit is where the problem originates, and it is worth being precise about how.

 

Where They Actually Escape

 

Nurdles travel by road tanker, rail hopper car, bulk shipping container, and 25-kilogram sacks, and every transfer between those modes is a loss point. Pellets escape from hose couplings during pneumatic transfer, from hopper discharge, from torn bags, from spillage on loading docks that gets swept rather than collected, and from dust extraction systems. The industry term for this is fugitive loss, and most of it is chronic and unremarkable rather than catastrophic: a handful here, a cupful there, repeated thousands of times a day across thousands of sites.

Those routine losses matter more than their individual size suggests, because of where they go. A pellet dropped on a concrete yard is not lost in any meaningful sense until it rains. Then it washes toward a stormwater drain, and stormwater drains discharge to rivers with little or no filtration. That is why the carousel's fifth slide names protected stormwater drains specifically, and why it's the single most cost-effective intervention available: a filter or sock on a drain at a pellet handling site costs very little. It intercepts the loss pathway at the only point where the pellets are still concentrated.

The catastrophic losses are rarer and far more visible. The X-Press Pearl, which caught fire and sank off Sri Lanka in 2021, released around 1,680 tonnes of nurdles, making it the worst plastic spill on record. The Toconao lost containers off Galicia in late 2023, producing a spill significant enough that researchers published a full chemical and hazard assessment of the recovered pellets, concluding they carried potential for environmental harm. A ship collision in the North Sea in March 2025 produced another visible sheen of pellets.

The balance between chronic and catastrophic loss is genuinely contested, and both deserve attention. Spills generate headlines and shoreline emergencies. Routine handling losses are invisible, continuous and probably larger in aggregate.

 

Why They Travel So Far

 

Three properties make a nurdle unusually mobile and unusually persistent.

It floats. Polyethylene and polypropylene, which make up most pellet production, are less dense than seawater, so spilled pellets sit at the surface where wind and current move them fastest. Pellets from a single spill have been recovered hundreds of kilometers from the loss point, and along coastlines in multiple countries.

It does not break down. Plastic does not biodegrade in any timeframe relevant to this discussion. Instead, ultraviolet light and mechanical abrasion make the pellet brittle, and it fragments into progressively smaller pieces that stay in the system as secondary microplastics and eventually as particles small enough for plankton to ingest.

It looks like food. A white or translucent two-millimeter sphere floating at the surface resembles a fish egg closely enough that turtles, seabirds, and fish routinely eat it. Because plastic occupies volume in the gut without providing nutrition, an animal that fills itself with pellets can starve while feeling full. Nurdles also adsorb hydrophobic pollutants from surrounding seawater, concentrating them on their surfaces, and those compounds can transfer into the fatty tissue of whatever eats them.

 

Why Nurdles Are Not Legally Dangerous

 

Here is the paradox that explains the regulatory lag, and it is worth setting out carefully because it is counterintuitive.

As of early 2026, plastic pellets are not classified as dangerous goods under the International Maritime Dangerous Goods Code. This is not an oversight. It is because nurdles fail the technical criteria. The hazard classification system assesses substances for properties such as acute toxicity, flammability, corrosivity, and bioaccumulation potential, and polyethylene pellets are chemically inert. It will not poison you, burn you, or accumulate in your tissue as a chemical. Judged as a substance, it is about as benign as a material can be.

The harm a nurdle causes has nothing to do with its chemistry. It comes from its physical form: durable, buoyant, bite-sized, visually similar to prey, present in astronomical numbers, and permanent. Those are not properties the dangerous goods framework was built to measure, because that framework was designed for cargoes that poison,explode,e or corrode.

What makes nurdles harmful is precisely what makes them unclassifiable, and the regime that governs hazardous cargo at sea has no category for a hazard of this kind. Proposals to assign pellets a dedicated UN number or to bring them under Class 9, the miscellaneous dangerous substances category, remain under debate at the IMO.

The practical consequence is that for most of the period during which this problem has been understood, the rules applying to a container of nurdles were the rules applying to any other general cargo. IMO guidance now recommends that shippers treat them as dangerous goods, using durable packaging, clearly identifying pellet containers in transport documentation, and stowing them under deck or in sheltered inboard positions rather than in the exposed outer tiers where containers are most often lost overboard. That stowage recommendation is specific, low-cost, and directly targets the dominant loss mechanism at sea. It is also voluntary guidance.

 

What Changed in 2025 and 2026

 

Two developments have moved this from recommendation toward obligation.

The European Union adopted Regulation 2025/2365, the Plastic Pellet Regulation, which Parliament approved in October 2025. It sets an explicit goal of zero pellet loss and requires mandatory spill-prevention measures at every stage of the supply chain, including adapted packaging and staff training. Operators handling more than 1,500 tonnes of pellets a year face the stricter requirements and must obtain certification of compliance from an accredited body. Carriers, both EU and non-EU, must submit annual reports on pellet losses. Maritime transport is within scope, strengthened relative to earlier drafts.

The criticisms are specific, not general. Operators handling under 1,500 tonnes a year submit self-declarations with one-off certification every five years and no independent oversight, which exempts a long tail of smaller sites from the parts of the regulation with teeth. Campaigners who worked on the file describe it as a real advance with loopholes intact, which seems a fair reading.

Separately, amendments to SOLAS Regulations 31 and 32 and to Article V of MARPOL Protocol I entered into force on 1 January 2026, requiring masters to report containers lost overboard and to declare whether dangerous goods are involved, including UN numbers where known. This does not classify nurdles, but it creates, for the first time, a mandatory reporting trail for container losses through which the worst pellet spills occur. You cannot regulate what you do not measure, and until this year container losses were substantially unmeasured.

Alongside both sits Operation Clean Sweep, the plastics industry's voluntary pellet loss prevention program, which has existed for decades. Its continued existence alongside a new binding regulation reasonably reflects how effective voluntary schemes proved to be.

 

Why Recovery Barely Works

 

The carousel's closing slide says prevention is far easier than recovery. The evidence suggests that understates the position considerably.

Consider the physical task. A spill disperses millimeter-scale, buoyant, pale particles across tens or hundreds of kilometers of coastline, where they mix into sand of similar grain size and color, lodge in seaweed wrack, and bury themselves in the upper layers of beach sediment. No mechanical method can separate them from sand at scale without removing the beach. Recovery is therefore done by hand with sieves and buckets, and the work continues for years. Sri Lankan beaches were still receiving X-Press Pearl pellets long after the initial emergency response concluded.

Weathering closes the window further. Pellets in the water for months become brittle and fragment under handling. Hence, the material becomes progressively less recoverable the longer it is out there, turning a difficult cleanup problem into an impossible one.

So the comparison is not between an easy option and a hard one. Prevention is a matter of filters, packaging specifications, training and stowage decisions, each of which costs a small amount of money at a known point in time. Recovery is largely unavailable after the first days, and what can be recovered is a fraction of what was lost.

 

The Best Solution Starts Before the Spill

 

The four measures on the final slide map cleanly onto the four places pellets are lost, which is why they are the right four.

Secure packaging addresses container failure and bag rupture. Careful handling addresses chronic fugitive losses at transfer points, the largest cumulative source and the least visible. Protected stormwater drains address the pathway by which land-based losses reach water, and are the cheapest intervention per pellet prevented. Safer shipping practices address the catastrophic end, where under-deck stowage and proper documentation make the difference between a container loss and a regional environmental emergency.

What has changed recently is that three of those four are moving from industry good practice into enforceable obligation, at least within one jurisdiction, and that container losses at sea are finally being reported. The underlying classification problem has not changed. Until the hazard framework finds a way to recognize a material as dangerous because of its persistence and physical form rather than its chemistry, nurdles will continue to travel the world as ordinary cargo, in enormous quantities, through a supply chain where every transfer is an opportunity to lose some.

 

Note: This article reflects the state of regulation as of November 2026, drawing on sources including EU Regulation 2025/2365 on preventing plastic pellet losses, IMO guidance and the SOLAS and MARPOL reporting amendments effective 1 January 2026, published assessment of the Toconao spill, and Fauna and Flora's analysis of nurdle pollution. Estimates of annual pellet losses vary widely between studies. A companion piece in this series covers the broader distinction between macroplastics, microplastics, and nanoplastics.