EPA Administrator Scott Pruitt has questioned whether human activity ranks as a main driver of global warming. (Pablo Martinez Monsivais/AP)

The Environmental Protection Agency has instructed two of its scientists and one contractor not to speak as planned at a scientific conference Monday in Providence, R.I., sparking criticism from some academics and congressional Democrats.

EPA officials confirmed Sunday that its researchers would not present at the State of Narragansett Bay and Its Watershed program but did not offer an explanation for the decision.

“EPA scientists are attending, they simply are not presenting, it is not an EPA conference,” EPA spokesman John Konkus said in an email.

The New York Times first reported the cancellations.

The conference marks the culmination of a three-year report on the status of Narragansett Bay, New England’s largest estuary, and the challenges it faces. Climate change features as a significant factor in the 500-page report, which evaluates 24 aspects of the bay and its larger watershed. The organizers intend to present a 28-page summary report of their findings in a news conference Monday.

“Narragansett Bay is one of Rhode Island’s most important economic assets and the EPA won’t let its scientists talk with local leaders to plan for its future. Whatever you think about climate change, this kind of collaboration should be a no-brainer,” Sen. Sheldon Whitehouse (D-R.I.) said in a statement. “Muzzling our leading scientists benefits no one.” Whitehouse is scheduled to speak at the event.

For roughly six years, the EPA has provided about $600,000 annually for each of more than two dozen national estuaries, including the Narragansett Bay Estuary Program, the conference’s host.

The program’s director, Tom Borden, said the head of the EPA’s National Health and Environmental Effects Research Laboratory Atlantic Ecology Division in Narragansett informed him Friday that the keynote speaker, division research ecologist Autumn Oczkowski, and another colleague in the lab, Rose Martin, would not be able to make presentations at the event.

“I was not given a clear reason why,” Borden said in an interview, adding that his team had worked closely with several of the agency’s scientists on protecting and restoring the bay. “It’s a terrific partnership to have EPA working with us.”

An EPA contractor who had contributed to two chapters of the report, Emily Shumchenia, was also told not to speak at the event. She and Martin were slated to take part in a panel titled “The Present and Future Biological Implications of Climate Change.”

Borden said the organizers invited Oczkowski and Martin because they were “independent scientists” who could offer valuable perspectives.

At least one senior regional EPA official is expected to attend the conference Monday; it is unclear whether the researchers previously scheduled to speak will go.

The estuary report, which was subject to extensive peer review and public comment, charts how Narragansett Bay is becoming cleaner but also faces challenges such as nutrient runoff and climate change.

The issue of the EPA’s approach to climate-change science has become even more fraught since Donald Trump became president, as Administrator Scott Pruitt has questioned whether human activity ranks as a main driver of the warming the globe has experienced in recent decades. Political appointees have removed pages from the agency’s website that address the issue and have canceled some grants supporting climate-change initiatives.

Robinson Fulweiler, a Boston University ecosystems ecologist who has studied the effects of climate change on marine life, called the situation an “abuse of power” by the Trump administration.

“The silencing of government scientists is a scary step toward silencing anyone who disagrees,” she said in an email. “The choice by our government leaders to ignore the abundant and overwhelming data regarding climate change does not stop it from being true or prevent the negative consequences that are already occurring and those that are on the horizon.”