Arizona Democrat Raúl Grijalva has passed away at 77 due to complications from cancer treatment, his office announced Thursday. He had revealed his diagnosis in April 2024, calling it “difficult to process.”

Grijalva was first elected to the U.S. House in 2002 and played a key role on the House Natural Resources Committee. A strong advocate for environmental issues, he was also a member of the Congressional Hispanic Caucus and chair emeritus of the Congressional Progressive Caucus.

“Rep. Grijalva was known for his kindness and humility,” his office stated. “He believed in treating everyone as equals, loved giving gifts, playing music, and getting to know people.”

Representing a solidly Democratic district near the U.S.-Mexico border, he won re-election in November for a twelfth term. A special election will be held to fill his seat.

His passing follows the recent death of Texas Rep. Sylvester Turner, further reducing House Democrats’ numbers.

Rep. Greg Casar (D-Texas) called him “a giant of the House and the progressive movement,” while Rep. Pramila Jayapal (D-Wash.) said he was “always on the side of the people.”

House Minority Leader Hakeem Jeffries (D-N.Y.) honored Grijalva as “a progressive warrior” and “a mentor to many.”