By Brendan O'Brien

(Reuters) - Wisconsin Governor Scott Walker on Wednesday signed a bill into law that bans the manufacturing and sale of personal care products containing tiny plastic beads that are known to pollute waterways.

The law makes Wisconsin one of seven states including Illinois and New Jersey to ban the tiny pieces of non-biodegradable plastic known as microbeads, often used as an exfoliant in soaps and toothpaste.

It bans manufacturing of microbead products at the beginning of 2018 and their sale at the beginning of 2019.

Walker, a Republican, has said he will announce in mid-July whether he will seek the party's nomination for the 2016 presidential election.

“We’re elated to finally have the microbeads bill signed into law,” said Amber Meyer Smith, director of government relations of Clean Wisconsin.

Microbeads are so small they often slip through wastewater treatment systems and end up in nearby waterways, according to the National Oceanic and Atmospheric Association.

In 2014, Illinois became the first state to ban microbeads after a team of researchers with 5 Gyres Institute, a California-based environmental group, found high levels of beads in 2012 from samples taken at Lakes Erie, Superior and Huron. Scientists have also found beads in the ocean.

Fish mistake microbeads for food and eat them, threatening the ecosystem and human health, according to Clean Wisconsin.

The Personal Care Products Council, a trade association representing the cosmetics and personal care products industry, supports bans on microbeads.

"We are guided by the core value to do the right thing based on the best available science when addressing product safety or the environmental impact of our products," the council said in a statement after the Illinois bill was signed into law.

(Reporting by Brendan O'Brien in Milwaukee; Editing by Mohammad Zargham)