WASHINGTON (AP) — Democratic U.S. Rep. Raúl M. Grijalva of Arizona, who championed environmental protection during his 12 terms in Congress, died Thursday of complications from cancer treatments, his office said.

Grijalva, who was 77, had risen to chair the U.S. House Natural Resources Committee and was the top Democrat on the committee until earlier this year. He had been absent from Congress as he underwent cancer treatment in recent months.

Grijalva’s office said in a statement, “From permanently protecting the Grand Canyon for future generations to strengthening the Affordable Care Act, his proudest moments in Congress have always been guided by community voices.”

Another Democratic House member, Rep. Sylvester Turner of Texas, died last week from health issues.

Grijalva, the son of a Mexican immigrant, was first elected to the House in 2002. Known as a liberal leader, he led the Congressional Progressive Caucus in 2008 and dedicated much of his career to working on environmental causes on the Natural Resources Committee. He stepped down from that position this year, after announcing that he planned to retire rather than run for reelection in 2026.

During his time in Congress, Grijalva championed protections for endangered species and wilderness areas, as well as stronger regulations on the oil and natural gas industries. He played a key role in writing the National Landscape Conservation System Act and the Federal Lands Restoration Act, which were passed and signed by President Barack Obama.

Grijalva had announced in April last year that he had been diagnosed with cancer, but would be able to continue his work. He also sought reelection and won easily in the blue-leaning district.

Condolences poured in following the announcement of the passing of Congressman Raúl Grijalva Grijalva, a Democrat, was first elected to the House of Representatives in 2003 and represented southern Arizona for more than two decades.

“I am devastated by the loss of Representative Raúl Grijalva and my heart is with his family and loved ones. He was a true champion for the people of our state,” said Gov. Katie Hobbs.

“A giant of our community has passed from our midst. Pima County is grieving at the sad news that U.S. Rep. Raúl Grijalva has died,” Pima County said. “Since he was a young man in his 20s to the day he passed, he worked in service to the people of Pima County, Southern Arizona, and the nation.”

“AZ lost a giant today,” said Attorney General Kris Mayes. “Raúl leaves a legacy that is unmatched. I am thinking of his family and loved ones.”

Sen. Ruben Gallego, D-Ariz., said, “Congressman Grijalva was not just my colleague, but my friend. As another Latino working in public service, I can say from experience that he served as a role model to many young people across the Grand Canyon State. He spent his life as a voice for equality.”