Billionaire oil tycoon Harold Hamm has donated $150 million to the University of Oklahoma to advance research into diabetes, a disease the 80-year-old energy executive has lived with since being diagnosed in his fifties. More than 40 million Americans live with diabetes, according to the American Diabetes Association.

“I’ve spent my life believing that when you see an opportunity to change the future, you don’t stand on the sidelines—you act,” Hamm said in a statement.

The gift is the largest in the university’s history and makes Hamm OU’s largest individual donor, with his lifetime giving nearing $250 million. In his honor, OU’s Oklahoma City health campus will be renamed the Harold Hamm Health Campus.

Of the new gift, $100 million will fund the campus’s broader work, including training health care workers and recruiting researchers. The remaining $50 million will go to the Harold Hamm Diabetes Center, with $30 million earmarked for the priorities of new director John Kirwan and $20 million for capital improvements and research infrastructure. The allocation connects the university’s broader health-care workforce and research needs with the diabetes center’s leadership priorities and physical research capacity.

Hamm’s 2007 lead gift established the Harold Hamm Diabetes Center, and he has given more than $50 million to it since. Over that time, NIH research funding tied to the center has grown from $5 million to $33 million, according to OU. Hamm also created the Harold Hamm International Prize for Biomedical Research in Diabetes, which recognizes and promotes lasting achievements in diabetes research.

Hamm founded Continental Resources in 1967 at age 21 and built the Oklahoma City–based company into one of the largest oil producers in North Dakota’s Bakken shale, a key front in the U.S. fracking boom. He still chairs the company, which has a market cap of $27 billion. Today, his net worth is estimated at nearly $18 billion.

Hamm’s influence also reaches Washington. This summer, he merged the Domestic Energy Producers Alliance, the oil advocacy group he founded in 2008, with the much larger Independent Petroleum Association of America, and an IPAA spokesperson told Politico he has “expressed an interest” in becoming its chair. President Donald Trump has also referred to Hamm as his “original oil guy,” according to Politico. On the policy side, Hamm backed the Affordable Insulin Now Act, a bill that sought to cap patients’ out-of-pocket insulin costs at $35 a month.

Investing in Oklahoma When It Needs It Most

Hamm’s gift is personal not only to his health but also to the place he calls home. Oklahoma ranks No. 49 in the nation for health care because of severe gaps in access, a high rate of uninsured adults, and poor health outcomes. Meanwhile, the Oklahoma Hospital Association reports critical shortages of health care workers across the state.

“If you look at hospitals in the state of Oklahoma, we have more than 90 hospitals that lose money on providing care to patients,” Rich Rasmussen, president and CEO of the Oklahoma Hospital Association, told local station FOX 25. “The only way they make up for that loss are in the supplemental Medicaid payments. These supplemental payments are the payments that Congress has cut.”

To be sure, the state has made some progress. The health campus has earned its first-ever ranking among the top 100 institutions for National Institutes of Health funding, placing it in the top 4% of NIH-funded institutions nationwide, according to OU. The Harold Hamm Health Campus also brings together six health professions colleges and the university’s graduate college—more than 4,100 students—to build a pipeline aimed at addressing those issues.

Hamm hopes his gift will do more than fill gaps.

“My hope is that this gift will help make Oklahoma a place where the next great medical breakthrough happens—where diseases are prevented, lives are saved, and, one day, diseases like diabetes are cured,” he said in the statement.

This story was originally featured on Fortune.com.