A new report by Public Employees for Environmental Responsibility is critical of a Park Service plan to reduce single-use plastics.
The nonprofit says other public lands agencies are acting faster on similar projects.
The Grand Canyon was once one of a handful of parks leading the way in reducing single-use plastics, until the Trump administration reversed the policy.
President Joe Biden has called for a renewed effort to restrict plastic pollution, and public lands agencies have made their own proposals.
The Bureau of Land Management, for example, wants to put a reduction in place by fiscal year 2027.
Colleen Teubner of PEER said the Park Service plan isn’t fast enough.
"Their plan is to phase single-use plastics out by 2032, which is a far longer time frame than we think is necessary," Teubner said.
She said one concern is that the policy could be reversed by a new administration before it even takes effect.
The National Park Service declined to comment.