One of the wealthiest people in the U.S. has died.

Texas billionaire oilman George P. Mitchell died at his home in Galveston on Friday.

According to the Associated Press, Mitchell is considered as the father of the process of hydraulic fracking. He was 94 years old, and reportedly died of natural causes.

He is preceded in death by his wife Cynthia, who passed away in 2009. The couple had 10 children.

You can read more on this story from the Houston Chronicle.