It was early in the day but already hot. As Chieko Kiriake wiped sweat from her brow, she searched for some shade. Suddenly, a blinding light appeared – an experience unlike any other for the 15-year-old. It was 08:15 on 6 August 1945.

“It felt like the sun had fallen – and I grew dizzy,” she recalls.

The United States had just dropped an atomic bomb on Hiroshima, Chieko's home city, marking the first use of a nuclear weapon in warfare. Although Germany had surrendered in Europe, Allied forces were still at war with Japan. Chieko, a student sent to work in factories during the war like many older pupils, staggered to her school, carrying an injured friend on her back. Many students were badly burned. She found old oil in the home economics classroom and applied it to their wounds.

“That was the only treatment we could give them. They died one after the next,” says Chieko. “Us older students who survived were instructed by our teachers to dig a hole in the playground and I cremated [my classmates] with my own hands. I felt so awful for them.”

Now 94, Chieko is among the few surviving hibakusha – the Japanese term for bomb-affected people. Nearly 80 years after the atomic bombings of Hiroshima and Nagasaki, these survivors are sharing their stories for a BBC Two film to serve as a warning for the future. Many hibakusha have lived with health problems, lost loved ones, and faced discrimination due to the atomic attack. Despite the sorrow, life began to return to Hiroshima.

“People said the grass wouldn’t grow for 75 years,” Chieko recalls, “but by the spring of the next year, the sparrows returned.” Throughout her life, Chieko has faced numerous brushes with death but believes a greater power has kept her alive.

Most hibakusha alive today were children during the bombings. As they have aged, global conflicts have intensified, making the threat of nuclear escalation feel more real to them.

“My body trembles and tears overflow,” says 86-year-old Michiko Kodama, reflecting on current conflicts like the Russian invasion of Ukraine and the Israel-Gaza war. “We must not allow the hell of the atomic bombing to be recreated. I feel a sense of crisis.”

Michiko, a vocal advocate for nuclear disarmament, speaks out to ensure the voices of those who died are heard and their testimonies passed on to future generations. She was seven years old, at school, when the bomb hit Hiroshima.

“Through the windows of my classroom, there was an intense light speeding towards us. It was yellow, orange, silver.” The blast shattered the windows, spraying debris everywhere and causing the ceiling to collapse. Michiko hid under her desk.

After the explosion, she saw her devastated classroom with trapped hands and legs everywhere. Crawling to the corridor, she heard her friends calling for help. Her father came and carried her home on his back. Black rain, a mixture of radioactive material and explosion residue, fell from the sky.

“It was a scene from hell,” Michiko describes. “The people who were escaping towards us, most of their clothes had completely burned away and their flesh was melting.” She vividly remembers a badly burned girl, around her age, with wide-open eyes. “That girl’s eyes, they pierce me still. I can’t forget her. Even though 78 years have passed, she is seared into my mind and soul.”

Michiko's family had moved just a few kilometers from their old home 20 days before the bombing, saving her life. Her old home was only 350 meters from the bomb’s epicenter. By the end of 1945, around 140,000 people had died in Hiroshima, and at least 74,000 in Nagasaki.

Sueichi Kido, who lived 2km from the Nagasaki blast, was five years old and suffered burns on his face. His mother shielded him from the worst impact. Initially believing a red oil can caused the explosion, his parents shielded him from the truth of the nuclear attack. Not all injuries were immediate; radiation poisoning symptoms and increased cancer rates appeared later.

Hibakusha faced societal discrimination, especially in finding partners. “We do not want hibakusha blood to enter our family line,” Michiko was told. Despite this, she married and had two children, losing her parents, brothers, and daughter to cancer. “I feel lonely, angry, and scared, and I wonder if it may be my turn next,” she says.

Kiyomi Iguro, 19 at the time of the Nagasaki bomb, married into a distant relative’s family but had a miscarriage attributed to the atomic bomb. “Your future is scary,” her mother-in-law told her. Kiyomi was instructed to hide her hibakusha status from neighbors. She visited the Peace Park in Nagasaki and rang the bell at 11:02, the time the bomb hit, to wish for peace until her recent death at 98.

Sueichi, who taught Japanese history at university, felt his hibakusha identity cast a shadow over him. Realizing his unique position, he felt a duty to speak out to save humanity. “A sense that I was a special person was born in me,” he says.

This enduring determination to prevent history from repeating itself is shared by all hibakusha.