PepsiCo and Coca-Cola are ending their memberships in the Plastics Industry Association, apparently at the urging of environmental groups who say the group is hampering efforts to reduce plastic pollution.

Greenpeace issued a statement Tuesday saying both companies had told the group that they planned to end their memberships in the association. The news site MarketWatch confirmed both departures, with a Coca-Cola spokeswoman saying her company withdrew earlier this year "as a result of positions the organization was taking that were not fully consistent with our commitments and goals." PepsiCo said it plans to leave by the end of the year.

Greenpeace pointed to the Plastic Industry Association's lobbying efforts against plastic bag bans enacted by local governments, which the group does through an affiliate, the American Progressive Bag Alliance. The environmentalist group also alleged the association works with the American Legislative Exchange Council—an organization that promotes conservative state legislation—to fight state and local efforts to reduce plastic pollution.

"Companies understand that they cannot publicly say they want to end plastic pollution, while financially supporting an association that lobbies for our continued reliance on throwaway plastics," Greenpeace USA Oceans Campaign Director John Hocevar said in a statement. "This is a victory for every person that spoke up and asked Coca-Cola and PepsiCo to put their money where their mouths are and tell the Plastics Industry Association to stop preventing plastic reduction efforts."

Greenpeace said it is joined in its campaign to pressure companies to leave the association by a mix of environmental groups and investment firms promoting sustainable businesses, such as Walden Asset Management, As You Sow, Sierra Club,and The Last Beach Cleanup.

In a statement to CEO Update, Patty Long, interim CEO of the Plastics Industry Association, said her group was aware that Greenpeace has been pressuring several prominent brands to leave her organization.

"This is unfortunate—consumer brands are integral to making sustainability commitments into realities, by working with their suppliers to make lasting change," Long said. "For example, our members work together to align their efforts to put recycling and sustainability at the forefront of their businesses.

"Once again, we invite Greenpeace to work with us to help implement meaningful and sustainable advances to improve our environment, such as modernizing and expanding recycling infrastructure," she added.

The Plastics Industry Association is not the only group to lose members this year over differences in environmental policy. Royal Dutch Shell announced in April that it would leave American Fuel & Petrochemical Manufacturers because it disagreed with the association on policies to address climate change.