William Schull, a U.S. geneticist who did extensive research into the health effects of radiation from the atomic bombings of Hiroshima and Nagasaki, died Tuesday of lung cancer in Houston, Texas, people close to him said. He was 95.

Schull came to Japan in 1949, four years after the bombs were dropped during World War II, as part of the Atomic Bomb Casualty Commission set up by the U.S. government.

He carried out a genetic survey of around 70,000 babies born in Hiroshima and Nagasaki and investigated the effect of radiation on them, including whether their parents' radiation exposure had affected their development.

After returning to the United States, he amassed notes and other documents from U.S. scientists and doctors involved in the research and made them public in the ABCC collection established at the Texas Medical Center Library in 1986.

Schull served as professor emeritus at the University of Texas Health Science Center at Houston and was a former vice chairman of the Radiation Effects Research Foundation, a Japan-U.S. joint research organization that succeeded the ABCC.

Radiation Effects Research Foundation Chairman Otsura Niwa said that current genetic research on survivors would not exist without Schull.

"He was someone worthy of respect, who got very close to the hearts of the survivors in his research," Niwa said.

In an interview with Kyodo News in December last year, Schull expressed his hope that there will be no repeat of atomic bombings, which were "a hell of a way to stop a war, but it did stop it."

A negative image of the commission remains in Japan due to its focus on scientific research and study rather than the provision of medical care, but Scholl defended the studies done there as "unique."

He said he had visited Japan almost annually since leaving, keeping in touch with Japanese people he met through the research.

"I've never come back to atone, or to apologize. I come back to learn," Schull said.