PORTLAND, Maine — A task force of residents, environmental advocates, business leaders and city officials began work Monday on an ordinance that may ultimately ban the use of containers made from polystyrene foam.

The Green Packaging Working Group, led by City Councilor Ed Suslovic, includes representatives from Environment Maine, the Maine Restaurant Association, the Maine Audubon Society, the Maine Grocers Association, several local businesses and city residents.

The City Council created the group to develop the ordinance and to identify ways to reduce the use of plastic bags.

Freeport Town Engineer Al Presgraves was on hand as a guest to describe his community’s experience since it banned some forms of polystyrene packaging in 1990. He said there has been little economic harm to the town’s businesses, and few, if any, problems with enforcement.

But some group members noted Freeport’s ban only applies to products that are packaged within the town.

Danny Bouzianis, a group member who owns several local Dunkin’ Donuts franchises, warned that using only paper cups in his stores rather than polystyrene ones would increase costs by $10,000 a year.

The School Department’s food service director, Ron Adams, said that costs quadrupled when the district decided to use paper lunch trays instead of polystyrene trays, going from 3 cents a tray to 12 cents.

“The perception in my customer base is that [polystyrene] trays are not a responsible way to go … but there is a huge financial impact,” Adams said.

On the other hand, he said, the effect is offset by savings in the cost of hauling trash. The paper trays can be recycled, while polystyrene is virtually impossible to reuse, several group members noted.

“There are extra costs, but there are savings along the way,” Adams said.

Other group members asked what the “hidden” costs of a polystyrene ban would be — for example, if businesses move because of the ban. But Suslovic noted that similar fears were raised when Maine passed its bottle-deposit law, and when Portland banned smoking in restaurants.

“We have to be careful about making automatic, gloom-and-doom predictions,” he said.

Throughout the discussion, the group had more questions than answers, looking for details about the economic trade-offs of foam packaging, disagreeing about measurements of the environmental effect, and wondering exactly which businesses would be affected.

But Suslovic said he plans to try to get the group to come up with proposed wording for the ordinance at the next meeting on April 8.

“Polystyrene doesn’t biodegrade, is virtually impossible to recycle, and has been identified by health experts as a carcinogen,” he said. “It’s time we work together to craft a policy that eliminates the risks associated with this product in a way that maintains the public health and minimizes the impact on local businesses.

“I am confident that this group is up to the task.”