Plastic microbeads are tiny pieces of plastic that have been used in many personal care products such as haircare, cosmetics, baby products and skincare to give these products texture and exfoliating properties. They're most commonly made from polyethylene, but can also made from other petrochemical plastics like polystyrene and polypropylene. The reason microbeads are so harmful is that when they're washed down the drain, they're a persistent polluter in our seas and can also be consumed by sea life. As of 2017, microbeads have been banned from use in cosmetics (or are in the process of being banned) in countries including Ireland, Canada, the Netherlands and the United States.