AS evidence accumulates about the environmental hazards of plastic shopping bags, the Bellingham City Council offers a template for how to go about banning them.

The Seattle City Council is taking up the subject again, two years after voters sharply rebuffed an attempt to discourage the use of the disposable bags with a 20-cent fee.

For starters, Bellingham bans single-use carryout bags outright. The ordinance passed in July takes effect next summer, to give consumers and retailers a chance to adjust.

Shoppers will be charged 5 cents for paper bags, which must include 40-percent recycled materials. Low-income state Basic Food clients using their electronic cards will not pay the nickel. Farmers' markets are also exempt from collecting the charge. Little plastic bags are still allowed for small retail purchases and restaurant takeout items.

The citizen group Bag It Bellingham worked for months to solicit support before the ordinance was introduced last spring. Local neighborhood associations backed the plan, signatures were collected on a petition and local supermarkets endorsed the ban.

Bellingham's ordinance addressed many practical issues, but also dealt head-on with the principal question that echoed in Seattle's failed effort: If plastic bags are bad, why not ban them?

Environmental arguments were persuasive in Bellingham. Plastic pollution in Puget Sound is a demonstrable menace to aquatic life.

The most dramatic example was in April 2010 when a beached whale in West Seattle was found to have more than 20 plastic bags in its stomach along with other debris.

Plastic bags can choke, starve, tangle and poison Puget Sound wildlife, said Katrina Rosen, field director of Environment Washington.

Her organization is helping host a Thursday presentation about the growing role of micro-plastics in Puget Sound — bits of plastic that provide a pathway for toxins.

Plastic bags have never been free. Their true costs are more evident. The Seattle City Council has a better story to tell and a better way to deliver it.