Pope Leo XIV. Photo: Collected

VATICAN CITY, April 26, 2026 (BSS/AFP) - Pope Leo XIV marked the 40th anniversary of the Chernobyl nuclear disaster with an appeal for atomic energy only to be used for peaceful purposes.

The deadly explosion at the Soviet-era plant "marked the conscience of humanity" and "remains a warning of the risks inherent in the use of increasingly powerful technologies," the US pontiff said at the end of a prayer service at the Vatican.

"I hope that at all levels of decision-making, discernment and responsibility will always prevail, so that every use of atomic energy may be at the service of life and peace," the 70-year-old said.

The 1986 explosion at Chernobyl, in current day Ukraine, was the worst civilian nuclear disaster in history.

A 2005 UN report put the number of confirmed and projected deaths from radiation exposure at 4,000 in the three worst-affected countries. Other NGOs and bodies have given higher tolls.

Some 600,000 people involved in the clean-up operation -- known as "liquidators" -- were exposed to high levels of radiation.