The warnings, and promises by Environmental Protection Agency chief Scott Pruitt of official action to confront the related health risks, came in a summit with small-town and state officials increasingly confronting water systems contaminated by the toxic substances.
Pruitt convened the conference as part of his pledge to step up EPA action on the family of contaminants.
The emails included an unidentified White House official calling a still-pending federal study on the chemicals a "public-relations nightmare" and EPA officials intervening in the publication of the report.
Patrick Breysse, head of the federal toxic substances agency involved in the still-unpublished federal study on the chemicals, said his office was called to its first case of public water system contamination from the chemicals only a decade ago.
Today his agency is working on dozens of sites contaminated with those chemicals, Breysse said.
The nonprofit Environmental Working Group estimated in a new study that more than 1,500 water systems serving as many as 110 million customers across the country may be contaminated.
In February, in the town of Blade, Delaware, local authorities abruptly ordered the 1,200 residents to avoid drinking or cooking with water from their taps, after tests showed dangerous levels of the chemicals.
"I don’t think anybody knew until this" that the compounds even existed, said Jean Holloway, who works with a Delaware nonprofit helping Blade residents deal with the contamination.
EPA spokesman Jahan Wilcox said the session was invitation-only and there was no room for the AP, but did not say what criteria were used in determining which news organizations the agency invited.
The EPA subsequently opened afternoon sessions of the hearing to the AP and other reporters.