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.”