The Trump administration is taking steps that could delay the cleanup of the Portland Harbor Superfund site by a decade or more, local officials said Monday.

In letters to the U.S. Environmental Protection Agency, the Oregon Department of Environmental Quality, the Yakama Nation and the city of Portland all raised an alarm over a draft technical work plan that involves re-testing the harbor's pollution and re-analyzing the standards that have been set for cleanup.

State DEQ and Yakama Nation officials argue that EPA has improperly negotiated in private with a group of parties financially responsible for the cleanup, named only as the Portland Harbor Pre-RD Group.

"EPA has apparently decided to usurp its regulatory authority in favor of a path that will lead to a remedial action that ultimately fails to protect human health and the environment," wrote Phil Rigdon, superintendent of the Yakama Nation Department of Natural Resources, in a Oct. 6 letter to the EPA.

Rigdon invoked the nation's right to "dispute resolution" to challenge the impending decision from the EPA.

After 16 years of work, the EPA issued a Record of Decision, the formal plan for cleaning up the site, in January, just before President Donald Trump's inauguration.

Advocates feared the administration might side with businesses responsible for the cleanup, rather than enforce an expensive cleanup. This is the first concrete step toward the Trump administration fulfilling those fears.

The decision on a new approach, which the EPA has told the state to expect as soon as this week, could, in essence re-start the process for a new decision about the level of habor cleanup.

"[M]oving forward with the agreement as proposed would unnecessarily delay cleanup," wrote Mayor Ted Wheeler and City Commissioner Nick Fish in an Oct. 6 letter to the EPA.

Multiple parties—including the city and state—have been working with the EPA to take the next step on cleanup, and officials fear the EPA could derail those efforts.

"We must move forward with the cleanup of the Portland Harbor, but the federal administration's latest direction to the EPA undermines the progress we've made," Governor Kate Brown says in a statement.

"Such a significant setback could impact Oregon's economy, as well as the long term health of the species and habitats the Willamette River supports. I urge the EPA to honor its commitment to work collaboratively and transparently with the state, city, and all responsible parties that have long worked toward a thorough and cost effective cleanup of the Portland Harbor."