Four members of a Prince George’s County-based plumbers, pipefitters and steamfitters union are presumed dead after Wednesday’s American Airlines flight crash near Ronald Reagan National Airport.

The four victims were part of the United Association of Steamfitters Local 602, according to a statement on Facebook from the union’s general president Mark McManus and the chapter’s business manager Chris Madello. The chapter represents workers in the Washington, D.C., area.

“These members will be forever in our hearts, and may God bless them and their loved ones,” the statement read. “May they forever rest in peace.”

American Airlines Flight 5342 collided with a Black Hawk helicopter near Washington, D.C., at about 9 p.m. Wednesday while approaching Ronald Reagan National Airport, according to the Associated Press. Both aircrafts then plunged into the Potomac River, the outlet reported.

No survivors have been found out of the 64 people on the plane and the three United States military members on the helicopter, the Associated Press reported.

In their statement, Madello and McManus expressed gratitude to first responders for their work. The union is focused on supporting the victims’ families, the statement said.

Prince George’s County Council at-large member and county executive candidate Calvin Hawkins said he is “heartbroken” by the crash and mourns the four union members.

“I extend my deepest condolences to the families, loved ones, friends and others who must cope with this devastating loss,” Hawkins said in his statement Thursday.