Last year, Illinois governor Pat Quinn signed the country’s first bill to ban the sale or manufacture of personal care products containing microbeads, tiny plastic exfoliators that have been proven to pollute waterways. Maine, New Jersey and Colorado have since passed similar laws, and a federal version of the bill is in the works.

One might expect this would please the many NGOs that lobbied hard for microbead bans. It doesn’t.

“Those were industry-written bills, pushed by industry,” says Stiv Wilson, director of campaigns at The Story of Stuff Project, a Berkeley, California-based environmental advocacy group.

These new laws are worded in a way that would allow manufacturers to swap the petroleum-based beads with bio-polymers that are supposedly designed to biodegrade, he says.

But it’s unclear how fast these alternative plastics degrade under different conditions. There are also questions as to whether these alternative microbeads could introduce any new, harmful chemicals into waterways. Bio-plastics, like their petroleum-based kin, may also absorb and introduce toxins into the food chain.

All of this means that in terms of environmental impacts, bioplastic microbeads may or may not prove to be good alternatives to conventional microbeads.

The tide may be turning against the biodegradable loophole. Last month, the California Assembly approved a bill that would not only ban the sale of products containing microbeads, but also preclude companies from swapping in alternative beads despite claims that they would biodegrade.

Wilson says he and other architects of this year’s bill, which include representatives from Californians Against Waste and the Clean Water Action, have made some concessions. But, he adds, “I think this year’s bill is better. It just says ‘we’re banning plastic beads and if industry wants to use biodegradable beads they will have to amend [the law] and the onus is on them to prove that alternative microbeads won’t be harmful, based on third-party tests.’”

Because California represents such a huge consumer market, if the bill passes and other states follow suit, major producers of personal care products – such as Johnson & Johnson, Procter & Gamble and Unilever – will likely need to give up any plans to replace current microbeads with biodegradable replacements.

Closing loopholes and opportunities?

“The way the CA bill is written is a concern for us,” says Max Senechal, vice president of strategy and commercial development for Metabolix, which makes polyhydroxyalkanoates (PHA), a family of bioplastics. The company is marketing a product called Mirel Micropowders as a bioplastic replacement for conventional microbeads.

Key to closing the door to products like Mirel Micropowders in California is a prohibition written into the California Public Resources Code that restricts products or packaging from being labeled “biodegradable”. It was put into place after some companies began labeling bioplastic packaging products with terms such as “biodegradable” without any certification those claims were true. In other words, there was no guarantee the products would biodegrade, and in what environmental conditions and over what time period.

Metabolix is now suffering for the actions of greenwashers who have indulged in unscientific advertising in order to capitalize on green marketing, Senechal says.

The industry also suffers from a lack of standards. The American Society for Testing and Materials (ASTM), an international standards organization, does not currently have a test specification or methodology that could be used to test the rate of biodegradation of microbeads in water.

Companies like Mirel might benefit from more testing. In 2012 a professor in the Department of Mechanical Engineering at the University of California, Chico, evaluated a few different types of bioplastic. He found that films, bags and bottles made from Mirel’s PHA passed the test’s requirement for 30% biodegradation in six months. In fact, the plastic biodegraded – meaning, it turned into carbon dioxide and water at roughly the same rate as the plant sample that Greene also tested as a control. After a year, just over 80% of Mirel’s PHA film had biodegraded.

Items made from polylactic acid, however, a bioplastic widely used in food packaging, did not fare as well in water. Less than 5% of the samples biodegraded after 180 days in seawater, and that did not improve much at the one-year mark.

To get a clear picture of the environmental impacts of bioplastic microbeads, researchers need a microbead-specific testing method and certification process. That is both because of the specific shape and weight of the beads and also because manufacturers might inject additives into microbeads in order to achieve some desired performance or color that could influence the rate of biodegradation. Additives could leach into the surrounding water or absorb toxins from the water. These are all unknowns.

Why bother with plastic?

Before microbeads, exfoliating products contained agricultural byproducts such as finely crushed apricot or walnut shells. Many still do. But Senechal contends that consumers prefer how the polyethylene plastic beads feel against their skin and the ease with which they wash off, and claims Mirel Micropowder beads duplicate that experience.

In a short video denouncing the use of plastic microbeads, the Story of Stuff contends that the real reason companies use plastic beads is financial: plastic beads are gentler on the skin, which means consumers are more likely to use them daily, compared to products with the rougher plant-based exfoliators. So in the end, it’s about selling more product, the group says.

But it’s starting to look like consumer brands may be backing off in the fight to allow bioplastic microbead alternatives.

The Personal Care Products Council, an industry group that represents major brands such as Johnson & Johnson, Unilever, and Procter & Gamble, has removed its formal opposition to California’s microbead bill and now, according to Story of Stuff, has taken a neutral stance. The industry group did not respond to a request for comment.

“We think we have the technology that provides a good solution for most of the current [non-biodegradable] microbead applications,” Senechal says. Because PHA is a denser material than the conventional plastic beads it would replace, Metabolix argues, it should settle into sediment tanks at wastewater treatment facilities instead of entering waterways. Metabolix, which has recently partnered with Honeywell to co-develop and market biodegradable microbeads to consumer care product companies, is not the only company that believes it has a viable bioplastic alternative to oil-based plastics. A Bay Area, San Francisco-based company called Mango Materials has also developed PHA plastic that it says is biodegradable both in and out of water. Plus, the company uses waste methane as its feedstock, thereby turning a harmful greenhouse gas into a useful product.

Wilson acknowledges that bioplastics could play an important role in offsetting the heavy reliance on petroleum-based plastics in the consumer market, but says there are still too many unknowns about their potential impacts as a replacement for conventional microbeads.

“I do think these [bioplastic] technologies need to scale up. I just don’t know that microbeads are their best application.”