Cal Kawamoto, who served in the state Senate for a decade and was a tireless advocate for Waipahu, died on Sunday after suffering a heart attack earlier this month. He was 73.

Carolyn Kawamoto, Kawamoto’s widow, said her husband had a heart attack on Sept. 5 and had been at The Queen’s Medical Center until his death on Sunday.

Kawamoto was elected to the Senate in 1994 and eventually became chairman of the Senate Transportation and Intergovernmental Affairs Committee. He was defeated in the Democratic primary in 2004 by state Sen. Clarence Nishihara after he was the subject of a campaign-finance investigation.

Kawamoto paid $21,250 to settle claims that he failed to report campaign donations over several years. The state Campaign Spending Commission concluded that the senator had not intentionally violated the law, but cited poor record-keeping.

The commission’s investigation was a disappointment to Kawamoto, who in 2004 proposed a bill that would have required the commission’s executive director to be approved by the Senate and would have given the Senate the ability to dismiss the executive director by majority vote.

After leaving office, Kawamoto transferred campaign money to the Waipahu Community Adult Day Health Center and Youth Day Care Center.

“He was a tireless and strong advocate for Waipahu,” said Nishihara (D, Waipahu-Pearl City), who attended Waipahu United Church of Christ with Kawamoto but added that the two men did not reconcile after the primary.

Nishihara said Kawamoto had been an early advocate for Hawaii’s Plantation Village. As a senator, Kawamoto also supported the establishment of the University of Hawaii-West Oahu.

Born April 14, 1940 in Pepeekeo in Hawaii County, Kawamoto was a graduate of Hilo High School and the University of Hawaii. He did post-graduate studies at Northern Michigan University.

Kawamoto spent two decades in the Air Force and was active in the Veterans of Foreign Wars Post 1572.

Kawamoto also led the Waipahu Community Foundation.

Jeffrey Higa, the executive director of Hawaii’s Plantation Village, said Kawamoto was instrumental in raising private and public money to establish the village and remember the region’s sugar plantation history. He said Kawamoto worked with other Waipahu leaders such as Goro Arakawa to preserve not only the physical infrastructure of plantation life but to capture the stories of plantation workers before they died.

“They wanted to preserve that for future generations,” Higa said.

Kawamoto is survived by his wife, Carolyn,  a son, Walter, and daughter, Nina. He is also survived by a brother, Paul, and a brother, Roy.

Memorial services are planned for Oct. 17 at Mililani Memorial Park and Mortuary.