Maine is banning single-use plastic bags at grocery check-out lines by April 22, 2020.
House Democrats said Monday that Democratic Gov. Janet Mills has signed a bill to limit plastic bags entering coastal waters.
The National Conference of State Legislatures says California, New York and all of Hawaii's counties ban plastic bags.
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Retail groups weary of varying plastic bag bans are supporting efforts in several states.
Maine will allow stores to charge at least 5 cents for recyclable paper or reusable plastic bags. Allowed plastic bags would have to withstand 75 repeated uses and be made from heavier plastic.
The fee wouldn't apply to restaurants.
Plastic bag manufacturers claim such bans will lead to thicker, reusable bags in landfills.