For the past year, they’ve come to the Restaurant Store in East Baltimore, at least one per day, looking for answers. Snowball sellers, deli owners, chicken box purveyors and others wanted to know what to do when Baltimore’s ban on expanded polystyrene foam, known colloquially as styrofoam, went into effect Saturday.

“We’ve even had a couple customers that didn’t know about it at all,” said Billy Wike, branch manager at the Restaurant Store on Kane Street, a sort of Office Depot for food sellers. “It’s definitely been a shock to them.”

The ban applies to just about everyone who sells food, including restaurants, supermarkets, hospital and school cafeterias and churches. Anne Arundel, Montgomery and Prince George’s counties already have banned foam products. A statewide ban goes into effect next July, the first of its kind in the country.

“It’s definitely a paradigm shift,” said Andy Attman, vice president of Acme Paper and Supply Co., which has been consulting with businesses as they prepare to make the switch. “People have been using the packaging that they’ve been using for 50 years.”

Ingrained as its use might be, polystyrene foam packaging, said Adam Lindquist, director of the Waterfront Partnership’s Healthy Harbor Initiative, “is a pretty horrible substance as far as the environment is concerned.”

The Inner Harbor’s Mr. Trash Wheel has picked up the equivalent of more than 1 million foam containers over five years, Lindquist said.

One of the most common plastics, foam breaks down into little pieces that attract other pollutants and can be nearly impossible to clean up. It isn’t biodegradable and it’s difficult to recycle. Wildlife might mistake the little white pellets for food.

Lindquist worked with local groups, including Blue Water Baltimore, Baltimore Beyond Plastics and Trash Free Maryland, to get the Baltimore City Council to vote last year to ban the substance to protect waterways and wildlife.

Washington, D.C., banned foam starting Jan. 1, 2016.

“We still find foam” during cleanups of the shoreline, said Trey Sherard, outreach coordinator at Anacostia Riverkeeper. But “we find a lot less big pieces.”

Sherard thinks much of the foam still found along the Anacostia today are small pieces left over from before the foam ban went into effect in 2016, a testament to just how persistent the problem is.

“One cup becomes literally hundreds of pieces, and then it becomes microplastics,” he said, ingested by humans and animals alike.

Alternatives can be found stacked in big brown boxes at the Restaurant Store. There’s a biodegradable clamshell made of sugarcane, compostable fiberboard boxes, and the mineral-filled polypropylene version that’s microwavable, recyclable and biodegradable and that Wike thinks will soon dominate the market. The polypropylene looks, feels and performs a lot like the foam containers. Other carryouts have turned to reusable plastic containers or insulated brown paper boxes.

In a back room of the store, sales manager Travis Hale sits at a computer monitor reviewing a spreadsheet that breaks down the differences in cost per unit. All the alternatives are more expensive than the squeaky white foam, a cost vendors expect to pass on to consumers. Foam clamshells retail for about 6 cents each, less than a third of the cost of the mineral version, which are 20 cents apiece.

“It’s definitely been a tough transition for us … but it’s going to be worth it in the long run,” Hale said.

Some local restaurants like the Ekiben, an Asian fusion eatery in Fells Point, have been using environmentally friendly packaging for years because they cater to eco-conscious customers, Wike said.

McDonald’s famously gave up polystyrene foam packaging for burgers in 1990 under pressure from environmental groups.

Other food sellers are not making the switch without complaint. Vicktoria Powers said her lease with the city forced her to stop using foam when she moved her deli into Broadway Market’s renovated north shed.

“They’re horrible,” Powers said of the biodegradable clamshells Vikki’s Fells Point Deli has used since dropping foam. “I hate them, and they’re heavy.”

She’s added 25 cents to the cost of each item to compensate for the extra price. And her carryout and catering customers complain the new containers get soggy on the bottom, she said.

“Some of them like it because they’re — I call them — ‘tree huggers,’?” Powers said with a laugh. “I just hope they don’t go to paper straws.”

Dining in is a simpler affair: Customers can eat their sandwiches off a piece of wax paper inserted into a reusable plastic basket. “Dine in, it’s not bad at all,” she said.

Powers and other critics of the foam ban have pointed out that many polystyrene alternatives still create waste in landfills. But there’s an important difference, Lindquist said.

“If it’s littered, it isn’t going to break down into 1,000 tiny pieces,” he said.

The ban applies only to food service facilities, meaning offices and church basements can continue to serve coffee in foam cups.

With the ban in effect Saturday, patrons at the newly renovated Cross Street Market ate French fries from foldable brown paper boxes and sipped soda from recyclable plastic cups.

“I don’t like it,” cashier Charrlene Cebrian of Steve’s Lunch said of the ban.

The longtime breakfast and lunch spot switched all its containers in recent days to prepare for the new rule, she said.

With cold drinks, “the ice melts faster” in the new beverage containers, she said. “The coffee gets cold faster.”

Baltimore Highlands resident Mike Haggerty said he doesn’t like how environmentally-friendly containers “melt” with hot foods. But Haggerty, who drives a tractor-trailer for FedEx Freight, thinks the ban will reduce litter in the city’s harbor and other waterways.

“It’s better for the environment,” said the 56-year-old, who was having lunch with his wife, Kim, at the market Saturday.

At Sobeachy Haitian Cuisine, where specialties include pan-fried marinated chicken and fresh juice drinks, owner Leo Fleurimond said he was using non-foam containers already for most foods. The exception was soups, which he will now serve in plastic.

While new to Cross Street Market, Sobeachy has operated for several years at farmers markets and festivals. Fleurimond said he used to put everything in foam containers and found it easier.

Some customers don’t like the biodegradable containers, especially for wet foods, he said. But Fleurimond thinks the environmental benefits outweigh the drawbacks, recalling a time he saw a bunch of littered foam on the beach in Ocean City.

“We’ll abide by the rules,” he said.

Attman acknowledges that a few restaurants will probably stick with the cheaper foam despiteSaturday’s deadline, at least until they get slapped with a $200 citation. The fine for ignoring the statewide ban taking effect next July will be $250.

“People will keep using it until they get caught,” Attman said.

D’Paul S. Nibber, director of legislative affairs for the city’s health department, said there will be some leniency in the first few months of enforcement.

Wike said he’s heard that from a few business owners who’ve come in to purchase supplies, but “it’s not something we ever suggest.”

Effective substitutes exist for nearly all the old foam containers.

There is, however, one thing Wike said he has yet to see work as well in non-foam form: snowball cups.

“We have paper cups that are really good for insulating hot drinks … but it just doesn’t work the same when it comes to cold.”

Baltimore Sun reporter Alison Knezevich contributed to this article.