Gov. Janet Mills has signed the single-use plastic bag ban into state law, after the Senate passed the measure last week. The law takes effect April 22, 2020, Earth Day.

The bill’s sponsor, Rep. Holly Stover (D-Boothbay), was concerned about plastics in the marine environment. Retailers’ groups supported the ban, which affects establishments of 10,000 square feet or greater. The groups cited the benefits of a single law for the entire state. Many towns and cities had already enacted their own plastic bag bans.

The law will let stores charge five cents for a paper bag or a heavier plastic baag that can withstand at least 75 uses. Maine joins New York, California and Hawaii in the single-use bag ban; Maine was the first state to ban styrofoam take-out containers. That ban takes effect in 2020.