The law, which will go into effect January 1, 2021, prohibits restaurants, caterers, coffee shops and grocery stores from using the to-go foam containers because they cannot be recycled in Maine.
Maine has become the first state to take such a step as debate about banning plastic bags or other disposable products is spreading across the nation.
While states like New York and California have banned single-use plastic bags, others such as Tennessee and Florida have made it illegal for local municipalities to regulate them.
Maryland's legislature also has approved bills to ban polystyrene, but it's unclear whether Republican Gov. Larry Hogan will sign the legislation. Democratic Delegate Brooke Lierman, the primary sponsor of the Maryland House bill, said banning foam products was the first step to curbing people's reliance on single-use plastics.
"Polystyrene cannot be recycled like a lot of other products, so while that cup of coffee may be finished, the Styrofoam cup it was in is not," Mills said in a statement to CNN affiliate WMTW. "In fact, it will be around for decades to come and eventually it will break down into particles, polluting our environment, hurting our wildlife, and even detrimentally impacting our economy."
The Maine law, originally proposed by Rep. Stanley Zeigler (D-Montville), also applies to plastic beverage stirrers.
Those who violate the law could face a fine of up to $100, News Center Maine reports.
"Maine has proven itself an environmental leader once again, this time in eliminating disposable foam containers that have become a common, costly, and deadly form of plastic pollution," said Sarah Lakeman, Sustainable Maine Director at the Natural Resources Council of Maine (NRCM), in a statement.