Seventy-five years ago last Thursday — August 6, 1945 — the United States dropped an atomic bomb on Hiroshima, Japan. Three days later, it dropped an atomic bomb on a second Japanese city, Nagasaki.

Experts estimate that more than 200,000 people lost their lives and hundreds of thousands were injured or exposed and survived. Generations later, families continue to reckon with the devastating toll of those bombings. To this day, no other nation on Earth has engaged in such an action.

The United States owes Hiroshima and Nagasaki an apology for committing atrocities against their citizens, but an apology is not enough. It’s a symbolic gesture, empty without a commitment to concrete action to ensure that such atrocities never occur again.

The United States owes the rest of the world a solemn promise to act to prevent the use of nuclear weapons and to engage in tangible steps toward their elimination.

As the only nation to ever use nuclear weapons in war, it’s past time for the United States to commit to never engage in a nuclear first strike, to take U.S. nuclear weapons off hair-trigger alert, and to engage in good faith in multilateral negotiations to reduce and eliminate our nuclear arsenal.

Instead, 75 years after the atomic bombings, we’ve withdrawn from most international treaties that reduce or limit the potential for nuclear war and we’re now considering re-engaging in live nuclear testing for the first time in decades.

I won’t relitigate the decision to drop atomic weapons on two civilian populations. In the United States, we’re still engaging in a false narrative that attempts to justify the unjustifiable.

Survivors of those atomic bombings, known as hibakusha, have been sharing their firsthand experiences for decades in an effort to ensure that those atrocities are never repeated. Most hibakusha who are still alive to continue to tell their stories today were children when the bombings occurred.

Their stories are heart-wrenching. The Hibakusha Appeal calling for the elimination of nuclear weapons explains, “With corpses charred black, bodies with their skins peeled off and with lines of people tottering in silence, a hell on Earth emerged. Those who narrowly survived soon collapsed one after another. For more than 70 years since then we have struggled to live on, afflicted by the delayed effects and by anxiety about the possible effects of radiation on our children and grandchildren. Never again do we want such tragedies to be repeated.”

We can’t change the past, but we can demand a better future. Nuclear weapons make us less, not more, safe. They pose one of the gravest threats to human health and survival.

Seventy-five years later, it’s past time for the United States to apologize and to commit to work toward a better, safer, healthier future free from the threat of nuclear war. It’s past time to eliminate nuclear weapons, for good.

Olivia Alperstein is the media manager at the Institute for Policy Studies and formerly was communications manager for Physicians for Social Responsibility, an organization that works toward the abolition of nuclear weapons. She wrote this for InsideSources.com.