WILLOW GROVE, Pa. — Environmental activist Erin Brockovich is weighing in on concerns residents are raising about drinking water contamination near two former U.S. Navy bases near Philadelphia.

Brockovich spoke by Skype Tuesday night to hundreds of residents who turned out for a public meeting organized by the New York law firm of Weitz & Luxenberg. The firm is gathering facts for a possible lawsuit stemming from water problems near the Naval Air Station Joint Reserve Base Willow Grove and the Naval Air Warfare Center in Warminster.

The federal government is offering free water and has alerted residents to possible contamination due to foam once used to fight fires at the bases.

Brockovich told the residents, "Together you can make the difference and you can fight and push for answers and for clean water."