PORTLAND, Maine — The city is a step closer to banning many commercial uses of expanded polystyrene, including the light plastic known by the brand name Styrofoam.

The Green Packaging Working Group, a task force appointed by the City Council earlier this year, voted 9-6 Monday to recommend the proposed ban to the City Council’s Transportation, Sustainability and Energy Committee.

The group then began discussing ideas for reducing the use of plastic grocery bags, including a similar ban.

Plastic packaging poses serious environmental and health dangers, according to the city. It also can be difficult or expensive to recycle. The working group, consisting of residents, environmental advocates, business leaders and city officials, began work last month to come up with ways of reducing the use of the packaging in Portland.

The ordinance recommended on Monday would ban the retail use of polystyrene food packaging or food-service ware within the city, and would prohibit the city and its vendors from using the material. The proposed law would take effect in 2015.

Prepackaged food would be exempt from the ordinance, and the city could make other exemptions in cases of emergencies or undue hardship.

Such exceptions were the focus of much of the 16-member group’s discussion before Monday’s vote.

Group member Matthew Fisher of Dart Container Corp. introduced an amendment that would nullify the ban if the city developed an effective recycling program for polystyrene. He also proposed nullifying the ordinance if it is superseded by state or federal law.

Both changes to the proposed ban were adopted.

Fisher also introduced an amendment exempting retailers from the ban if they collected polystyrene containers in their stores and recycled them. That change provoked sharp discussion.

“What happens if someone walks out of the store with a [polystyrene] cup?” asked City Councilor Ed Suslovic, chairman of the working group. “My concern is from a practical standpoint.”

Another group member, Portland resident Sally Trice, said, “If someone buys take-out, the [polystyrene] is going to end up in the trash.”

But Fisher said that if retailers were willing to make an investment in recycling polystyrene, they should be able to use it. He also said whether or not customers actually use a recycling service is a matter of “personal responsibility.”

The amendment failed on a 9-5 vote, with one group member abstaining.

The proposed ordinance now goes to the TSE Committee for review and could be on its agenda as soon as June 19. The proposal would then have to be referred to the full council and be approved before becoming law.

Meanwhile, the working group has begun tackling problems associated with the ubiquitous plastic bags used by grocery stores and other retailers.

To begin the discussion, Suslovic invited Josh Dow, a freshman at Casco Bay High School, to brief the group. Dow drew his remarks from an environmental science project he recently completed as part of the school’s award-winning Sustain ME program.

Dow said the plastic bags are an environmental hazard and that he saw 30 bags littering the streets on his way to City Hall Monday. He recommended that the city adopt a deposit-return program for the bags, similar to the state program for beverage containers.

He also noted that while most types of plastic bags take 1,000 years to decompose back into the environment, a new, highly biodegradable form of plastic bag is now available.

“There are 102 billion of these bags used each year. Where do they all go?” Dow asked. “It’s a monumental problem.”