Hundreds of yellow, fluffy blobs are storming the beaches of northern France.

And, while no one knows exactly where they came from, these strange invaders may offer yet another telltale sign that the seas are teeming with trash.

In this case, French authorities have identified the balls of goo as paraffin wax, a petroleum derivative that’s used to manufacture everything from cosmetics to crayons to food additives.

The culprits, according to a conservation group called the Sea-Mer Association, are likely the commercial ships that ply the waters along the country’s Opal Coast.

"This product is carried by ships, which are specialized for this, and once they have discharged their cargo in the port and once they leave the port, they are allowed to wash their tanks then to throw this residue overboard in the sea," Jonathan Hénicart, president of the Sea-Mer Association, told the CBC.

What are the rules?

Yellow ball in hand on beach Authorities say the balls are harmless to people and animals. (Photo: Sea-Mer Association)

Paraffin residue doesn’t sink, according to LiveScience, but instead gathers into balls that bob along the ocean surface until eventually making beachhead.

The trouble is, Hénicart explained, the ships are only permitted to wash their tanks far from shore and rinse out the gunk in limited quantities.

Instead, he suggests, someone decided to do it close to shore. And all at once.

Now, some of France’s most famous beaches — Le Touquet, Wimereux, La Slack, Le Portel, Equihen-Plage — are covered in clumps of that oily residue.

Not just an eyesore

paraffin ball on rocks at beach in France Environmentalist say these little yellow balls find their way into the food chain at great peril to wildlife. (Photo: Sea-Mer Association)

It wouldn’t be the first time someone cut a corner.

In May, beaches along England’s North Yorkshire coast were the scene of a similar invasion.

At the time, local councillor Nick Edwards urged the public to keep calm and tourist on.

“While the presence of paraffin wax on the coastline should not deter people visiting our beaches, we ask people to use common sense, not handle the substance and also keep dogs and children away from it,” Edwards told the BBC.

In this most recent case, French authorities are also urging beachgoers to not run in terror from the oily orbs, claiming they hurt neither people nor flora and fauna.

Conservationists like Hénicart beg to differ.

“Seagulls ingest this kind of product,” he told CBC. “The problem is also that even if we say that it is not toxic, the quantity, the enormous quantify, makes it toxic because the local wildlife will live with this.”

Indeed, on the iconic beaches of France they may only be temporary eyesores. But for animals that call the sea their home, these wounds may run a lot deeper.