The clothes on our backs may be the latest threat to our health and existence.

Synthetic clothing, sportswear and fleece jackets shed tiny plastic particles when washed.

These contaminate seafood and drinking water.

Plastics foes have condemned single-use products such as straws, drink bottles and coffee cups.

Now synthetic clothing is gaining attention.

Microplastics have turned up in seafood, drinking water, beer, honey and sugar, according to studies, but the impact on human health is unclear.

Each year, more than a half-million metric tons of microfibers enter the ocean from washing synthetic textiles, according to the International Union for Conservation of Nature and Natural Resources.

That’s the equivalent of 50 billion plastic water bottles, the Switzerland-based group reported.

While all clothing sheds fibers when washed, synthetic particles, unlike wool and cotton, don’t biodegrade.

Most washing-machine filters don’t trap the tiny particles.

Sewage treatment plants capture some but not everything.

More than 22 million metric tons of microfibers are estimated to wash into the oceans by 2050, according to the Ellen MacArthur Foundation.

Manufacturers are looking for ways to curb microfiber shedding.

They have found that how fibers are woven and clothes are washed matters.

Microfibers less than 5 millimeters long come from other things like tires, toothpaste and marine coatings.

The US has outlawed personal care products containing tiny plastic beads, such as facial scrubs and soaps. Textiles appear to be a much bigger problem, contributing 35% of primary micro-plastics in the oceans.