They provide color and texture to our toothpaste, exfoliate dead skin particles from our bodies in creams and washes, and provide, perhaps, a small degree of luxury to otherwise rote hygiene rituals. Small and indiscriminate, microbeads––small, plastic particulates found in a wide array of hygiene products––are as forgettable as the gels and liquids that contain them as they wash down the shower or sink drain in the billions.

But activists claim that microbeads are clogging marine ecosystems, polluting seafood, and putting seafood consumers at risk. On Tuesday, Senate Democrats introduced legislation -- supported by members of both parties -- that would amend the federal Food, Drug, and Cosmetic Act to halt the manufacture and sale of microbeads found in personal care products within a few years. The legislation comes days after the California State Assembly approved a measure that would ban them in personal care products with a 58-11 vote.

"Microbeads seem like a nice way to get extra 'scrub' in your soap, but they pose a very real danger to our Great Lakes," Sen. Debbie Stabenow (D-Mich.), who sits on a Senate committee to protect the Great Lakes, said in a statement. "Researchers are finding these bits of plastic building up in our lakes, rivers and streams. When we see these kinds of things are threatening our Great Lakes and potentially threatening fish populations, we need to take swift action."

Contextualized in an era of unprecedented concern over environmental pollution and the planet's climate, California's proposed ban received widespread national attention––the Senate bill faces a similar future. But the fight against the tiny plastic bits has been raging quietly for years––there's even an app to help consumers discern which products might contain them.

Generally smaller than one millimeter, microplastics in cosmetics are made of either polyethylene, polypropylene, polyethylene terephthalate, polymethyl methacrylate, or nylon. They are used most widely to create an abrasive character in exfoliating scrubs, but also, apparently, as color in toothpastes. Even though they're approved by the Food and Drug Administration, dentists have raised concerns that in toothpaste, microbeads could cause more problems than they're worth, citing cases of beads getting lodged in users' gums where they can foster bacteria and lead to gum disease.

A big concern is that microbeads are not biodegradable.

Environmentalists have their eyes on bigger fish. The specific makeup of a given microbead isn't necessarily as important as the fact that it isn't biodegradable and is small enough to pass through wastewater control systems, flowing more or less directly from the drain and into oceans and seas. It's there, they say, that the billions of accumulating tiny bits of plastic are wreaking havoc on sealife and posing a threat for consumers.

Because of their small size, microbeads can pass for plankton and other small sea creatures that provide a key source of food for many aquatic species. Not only can the beads clog the digestive systems of sea creatures, but they can carry pollutants up through the food chain and into the food we eat, according to Beat the Microbead, an international campaign fighting to eliminate the beads from cosmetics. The 5 Gyres Institute, which tracks and analyzes plastic pollution, estimates that a single tube of facial scrub can contain more than 300,000 microbeads.

Recent research on plastic pollution in the Great Lakes region found that microbeads play a substantial role there: in Lake Michigan, for example, each square kilometer of water holds an average of 17,000 microbeads. Moreover, the petroleum found in their plastic tends to attract other pollutants like DDT, PCBs, and industrial chemicals like flame-retardents, worsening the prospective consequences from ingestion by both wildlife and nearby consumers, according to the Watershed Council.

While it would be the most comprehensive restrictions yet on microbead use, the Senate measure is just the latest effort to impose wide-ranging bans on the particles. Along with California's proposed across-the-board bans, six states have enacted legislation restricting microbead use, the New York Times reports. Illinois, Maine, New Jersey, Colorado, Indiana, and Maryland have active restrictions, while other states, like Michigan, Minnesota, Washington, and Oregon are considering similar legislation.

How has industry responded?

Many popular products on the market contain microbeads, yet cosmetics manufacturers have responded. Johnson & Johnson, Procter & Gamble, and Unilever have all made pledges to phase out polyethylene microbeads from some of their products, while other, smaller companies are experimenting with naturally occurring plastics, like the kind produced in mushrooms. (California's ban would both synthetic particles, as well as biodegradable ones. Activists say that claims of biodegradability are suspect, since many materials need extreme conditions to quickly and properly degrade.)

Nevertheless, the strains of product redevelopment on the scale of a brand like Clean & Clear, owned by Johnson & Johnson, is time-consuming and expensive, and companies don't hesitate to say as much. "We believe the current bill in California is overly restrictive, inhibits innovation and does not allow for current and future advancement in biodegradable exfoliate alternatives," a Johnson company representative told the New York Times.

To this stance, critics point to fashion world-vetted products that use alternative exfoliating agents like ground up nut shells or wax beads. And when natural alternatives are out there, why would reach for conventional microbead products?