Washington (CNN) Journalists weren't the only ones shut out from the Environmental Protection Agency's conference this week on chemically contaminated drinking water. Many victims of water polluted by per- and polyfluoroalkyl substances were also left out, and are struggling to get clear answers about the dangers to their communities.

The EPA's PFAS National Leadership Summit landed in the spotlight because the Trump administration has withheld a Department of Health and Human Services report on the chemicals' health risks, and because the agency blocked some reporters, including from CNN, from covering a speech by EPA Administrator Scott Pruitt. After an Associated Press reporter was physically shoved out of the building, the EPA allowed reporters to attend about four hours of the two-day conference.

A list of invited organizations provided by the EPA, as well as CNN's conversations with multiple attendees, turned up just two representatives of local advocacy groups who received invitations. Experts have said millions of Americans live in communities where PFAS contamination is a problem.

Rep. Dan Kildee asked the EPA inspector general to look into the meeting after the agency did not allow a member of his staff to attend the second day of the conference. Kildee is a Michigan Democrat whose district includes Flint, where residents still question the safety of the drinking water, and Oscoda, where water contamination is linked to firefighting foam used at a former military base.

Multiple attendees, including several from environmental groups that have questioned Pruitt's actions at the EPA, described the meeting to CNN as primarily attended by state and federal regulators. They noted a chemical industry official gave one of the opening presentations, and several voiced frustration that victims' voices were not given a similar platform.

"Many of the communities that have been impacted were not represented," said Scott Faber of the Environmental Working Group. "I think what you missed with that is you missed the sense of urgency that these families are feeling."

Faber said conference organizers could have highlighted "the voices of people who have been directly impacted by these chemicals, just to remind the regulators that there are real people who are being directly impacted."

Several individuals who did not get in described their efforts to reach out to the EPA. Shaina Kasper of the Toxics Action Center said members of a national PFAS coalition she coordinates had written to the agency and their congressional delegation asking for invites. Laurene Allen, a counselor who became concerned about water contamination and co-founded Merrimack Citizens for Clean Water, signed on to that letter. EPA officials responded that the meeting would be primarily for state regulators -- which she said came off as "patronizing" and discounted her role as a stakeholder.

"Having a seat at the table is very important," Allen said.

The EPA is preparing a national plan to deal with per- and polyfluoroalkyl substances, which are used in manufacturing and many household products. Contaminated water has been found coming from drinking wells near current and former industrial sites, as well as military bases and airports where chemical firefighting foam has been used. Pruitt said the plan would include a legal limit for PFAS in water, and another official said the plan will be rolled out this year.

Peter Grevatt, director of the EPA's drinking water office, said this week's national meeting would be followed by as many as five regional meetings.

"We do need to hear very clearly from all of the stakeholders as we're working towards this," he told conference attendees.

In response to questions for this article, EPA spokesman Michael Abboud provided a list of organizations invited to attend. Abboud, however, did not provide information about why several community groups that had requested to attend were denied.

"I think that's really great that they're going to do the stakeholder meetings," said Ansje Miller with the Center for Environmental Health. But, she added, "I don't think that at all dismisses the concerns that folks weren't allowed in the meeting in the first place."

The two representatives of local groups who did attend were notified of their invitations just days before the conference. The invitations, they said, included a short one-on-one with Pruitt.

Andrea Amico said requests from her New Hampshire group, Testing for Pease, were initially turned down, until the top EPA official in New England appealed directly to Pruitt.

"It just doesn't seem right to exclude the perspective of people who are actually facing this issue on a day-to-day basis," Amico said.

She co-founded the group in response to toxins linked to a former Air Force facility in coastal New Hampshire, and realizes that her counterparts in other communities are skeptical the federal government will step up. But she was encouraged by Pruitt's pledge to develop legal concentration limits for the chemicals and she said of the EPA, "They deserve, in my opinion, the benefit of the doubt."

Mayor Rob Allen of Hoosick Falls, a music teacher who ran for office in his New York town after the discovery of contamination from nearby industrial sites, called the PFAS issue "exceedingly important to our village." Last week, the top EPA official in his region told him he could attend, but Allen said people at home also wanted to watch.

"The first day of the summit, the first hour -- and only the first hour -- was available via livestream, and that irked people in our community, because they wanted to see the whole thing," he said. Blood testing showed PFAS concentration levels in his body above the national average, and his children had around twice the level of concentration he has, Allen said.

The presentation from the American Chemistry Council at the meeting "kind of came across as an infomercial for the great new ways they are using these chemicals," he said.

At the conference, the American Chemistry Council's Jessica Bowman touted the industry's "innovation" in developing new products, which she said "have significantly improved hazard profiles compared to the legacy products."

"Today's PFAS are critical and continue to enable a myriad of applications that are vital to the US and the global economy," Bowman said.

Pruitt has been criticized for appearing to have a close relationship to the chemical industry. He has met twice with the American Chemistry Council, including once earlier this month, and spoke at a council event in South Carolina last November, according to his calendar.

During his tenure, the EPA turned down a petition to strengthen its ban on the controversial pesticide chlorpyrifos , which some scientists believe is linked to nervous system issues but its manufacturer has defended as safe. The agency blocked chemical safety rules developed under the Obama administration following the 2013 fertilizer plant explosion in West, Texas, that killed 15 people. And recently released internal emails show the HHS report into PFAS has been held from public release since January, when a White House official voiced concern the release could be a "potential public relations nightmare."

Neither the EPA nor the American Chemistry Council commented on the relationship.

An official from the HHS office that prepared that report, Patrick Breysse, told conference attendees on Tuesday the report would be released soon, once a communications plan could be completed.

Breysse spoke at a panel that also included the only presentation by a member of a nongovernmental group advocating for clean water. Erik Olson, of the Natural Resources Defense Council, told CNN later that he had "never seen the routine exclusion of the public" from an EPA event like this, but that it was "entirely consistent" with the Pruitt approach to similar meetings.

Rob Allen and Amico, the advocates who did attend, both said they met one-on-one with Pruitt, and advocated faster federal action on PFAS.

"I'm going to give the EPA the opportunity to make good on the promises they made in this summit," said Amico of Testing for Pease. "If they don't, the community will hold them accountable."