WASHINGTON — Ads say the wash can gently scrub dirt and oil from pores, leaving behind a refreshing sensation or tingly feeling. But those colorful little balls placed in face wash and toothpaste can do much more than just exfoliate or whiten teeth – they can also introduce harmful plastics to nature’s waterways and human stomachs.

Aimed at preventing further pollution and ensuring consumer safety, advocates say a new federal ban on microbeads in cosmetic products is a good step forward, but is not enough. More broadly, they say, beauty industry standards are in need of an overhaul.

The Microbead-Free Waters Act of 2015, signed into law by President Barack Obama in December, requires companies to stop selling and distributing cosmetic products containing “intentionally added plastic microbeads” – defined by the law as plastic particles less than 5 millimeters in size. The beads fall under the larger category of microplastics and are used for exfoliation to remove layers of dead skin or stained tooth enamel, and are not biodegradable.

The new law states that manufacturers are not allowed to make any “rinse-off cosmetics” – products that can be washed down drains after use – containing the beads after July 2017. That step is a lead-in to sales of such products being halted in 2018. Bans on bead-containing rinse-off cosmetics that qualify as nonprescription drugs take effect in 2018 and 2019.

The measure is a fairly rare amendment made to the Federal Food, Drug, and Cosmetic Act – which was signed into law in 1938 by President Franklin Delano Roosevelt – in that it specifically targets cosmetics. In fact, the cosmetics section of the law “regulates a $200 billion industry” and is relatively short, said Lindsay Dahl, director of policy and partnerships for cosmetics company Beautycounter.

“We’re in the dark ages when it comes to consumer safety in the beauty industry,” Dahl said.

The nationwide microbead ban was approved as a result of environmental and health organizations increasing public awareness. The advocacy work helped create a consumer backlash against cosmetics containing plastics, said Dahl, whose company urges the use of all-natural beauty products.

“The American public is realizing that we’ve taken for granted that the products on shelves have somehow been assessed for safety,” she said. “When someone is going to buy an exfoliator, they assume no one would put something in there that would cause widespread ecological harm.”

For humans, ingesting plastics over an extended period of time can lead to negative health impacts such as hormonal imbalances, Dahl said. Those imbalances, in turn, can affect how reproductive organs function.

A recent report published in the journal Environmental Science and Technology concluded 8 trillion microbeads are released into aquatic habitats daily – a volume that could cover over 300 standard tennis courts. Collecting them from the water, however, would be a “lost cause,” said Chelsea Rochman, a marine ecologist and one of the authors of the report.

“To get to them you would end up killing a lot of animals,” she said. “To get the really small stuff, you would have to drag a really fine mesh. It’s time-consuming and you’ll catch fish and plankton in its wake.”

Because some particles are so small they can slip through filters, microbeads can enter waterways through wastewater treatment plants. But 99 percent end up in solid waste that is used as agricultural fertilizer, then enter aquatic habitats through runoff from places like farms.

When they get into the water, the beads absorb chemical toxins before being consumed by aquatic organisms, which are then caught and eaten by humans.

“Microplastic has been found in oysters and mussels that we eat, species of fish in the supermarket and sea salt,” Rochman said.

Major companies such as Procter & Gamble, Johnson & Johnson and Unilever have already pledged to stop using microbeads in products. Yet despite the ban’s success in Congress last year, concerns remain that it may not be as effective as needed.

“Microplastics come from other sources, not just cosmetics,” said Jeroen Dagevos, head of programs with the Plastic Soup Foundation, a Dutch environmental organization. “Cosmetics are the largest source, but the U.S. might need to expand legislation to include other products.”

Passage of the microbead ban also emphasizes the need for more restrictive legislation to govern the beauty industry, Dahl said.

“The plastic microbead ban is a major step forward in overhauling our cosmetic safety laws,” she said. “It shows that there’s an appetite in Congress to take on an issue like this. It also gives a lot of momentum for Congress to prioritize safe beauty and reforming our cosmetic laws in 2016.”

The absence of regulatory legislation protecting people from ingesting plastics or putting products with harmful chemicals, such as lead, on their bodies has been a result of consumers not getting good information about what their cosmetics contain, Dahl said.

“When people make the big assumption that we have laws on the books that are looking out for us, they don’t demand things that they don’t realize are an issue,” she said.

Still, the ban’s success shows the impact consumers can have on the industry, Dagevos said.

“Maybe some people are really happy with the little glitter stuff in their shampoo, but once you realize you’re washing your hair with plastic it doesn’t give you a very good feeling,” he said. “I think in the end, everyone is very happy with this result.”