Microbeads are spheres less than 5mm in diameter, typically made of plastic, and used in body care products including toothpaste and body scrub. The particles are too small to be filtered out by sewage treatment plants. Once in the aqueous ecosystem, the microbeads readily absorb toxins; fish consume these contaminated microbeads, thereby moving the toxins up the supply chain to humans. The microbeads also aggregate into plastic debris patches causing dead zones. In the US, following the lead of States such as California, on 2015 December 28, the federal government legislated a 2017 ban on plastic microbeads; the California law also bans biodegradable microbeads.