In February 1991, Koch was a passenger on board USAir Flight 1493 when it collided with another aircraft on a runway at Los Angeles International Airport, killing 35 people.
Koch survived and said in an interview in 2014 that it helped change his life and prompted him to become "tremendously philanthropic".

In 1992, Koch was diagnosed with prostate cancer.
He underwent radiation, surgery, and hormone therapy, but the cancer repeatedly returned.
Koch said he believed his experience with cancer encouraged him to fund medical research.

Following Jacqueline Kennedy Onassis' death in 1994, Koch purchased her 15-room apartment at 1040 Fifth Avenue.
In 1996 he married Julia Flesher; The apartment wasn't roomy enough after the birth of their third child, so Koch sold it to billionaire Glenn Dubin in 2006 and moved with his family to 740 Park Avenue.

Koch died at his home in Southampton, New York, on August 23, 2019, at the age of 79.
Koch's wife, Julia Koch, and their three children inherited a 42% stake in Koch Industries from Koch upon his death.
In February 1991, Koch was a passenger on board USAir Flight 1493 when it collided with another aircraft on a runway at Los Angeles International Airport, killing 35 people. Koch survived and said in an interview in 2014 that it helped change his life and prompted him to become "tremendously philanthropic".
In 1992, Koch was diagnosed with prostate cancer. He underwent radiation, surgery, and hormone therapy, but the cancer repeatedly returned. Koch said he believed his experience with cancer encouraged him to fund medical research.
Following Jacqueline Kennedy Onassis' death in 1994, Koch purchased her 15-room apartment at 1040 Fifth Avenue. In 1996 he married Julia Flesher; The apartment wasn't roomy enough after the birth of their third child, so Koch sold it to billionaire Glenn Dubin in 2006 and moved with his family to 740 Park Avenue.
Koch died at his home in Southampton, New York, on August 23, 2019, at the age of 79. Koch's wife, Julia Koch, and their three children inherited a 42% stake in Koch Industries from Koch upon his death.
David Koch