Who says there’s never any good news? After more than 30 years and tens of millions dead — mostly children — the World Health Organization has ended its ban on DDT. DDT is the most effective anti-mosquito, anti-malaria pesticide known. But thanks to the worldwide environmental movement and politically correct bureaucrats in America and at the United Nations, the use of this benign chemical has been discouraged in Africa and elsewhere, permitting killer mosquitoes to spread death.

I don’t expect any apologies from the people who permitted this to happen. But I am thankful this nightmare is ending.

DDT was banned by President Nixon’s Environmental Protection Agency in the early 1970s, after Rachel Carson’s book, “Silent Spring,” claimed to show that DDT threatened human health as well as bird populations. But some scientists found no evidence for her claims. Even if there was danger to bird eggs, the problem was the amount of DDT used, not the chemical itself.

Huge amounts of the chemical were sprayed in America. I’ve watched old videos of people at picnics who just kept eating while trucks sprayed thick white clouds of DDT on top of them. Some people even ran toward the truck — as if it were an ice-cream truck — they were so happy to have mosquitoes repelled. Tons of DDT were sprayed on food and people. Despite this overuse, there was no surge in cancer or in any other human injury.

Nevertheless, the environmental hysteria led to DDT’s suppression in Africa, where its use had been dramatically reducing deaths. American foreign aid could be used to finance ineffective alternative anti-malaria methods, but not DDT. Within a short time, the mosquitoes and malaria reappeared, and deaths skyrocketed. Tens of millions of people have died in that time.

DDT advocates pointed out that the ban amounted to mass murder. But they could not move the rich, white, environmental dogmatists who reflexively condemn all kinds of chemicals, and presumably lost no sleep when millions of poor African children died.

But now this has changed. Last month, the World Health Organization announced that it supports indoor spraying of DDT and other insecticides “not only in epidemic areas but also in areas with constant and high malaria transmission, including throughout Africa.”

“The scientific and programmatic evidence clearly supports this reassessment,” said Dr. Anarfi Asamoa-Baah, WHO assistant directorgeneral for HIV/AIDS, TB, and malaria. “DDT presents no health risk when used properly.”

The World Health Organization now calls DDT the “most effective” pesticide for indoor use. Some environmental groups have also changed their anti-DDT tune, including Greenpeace, Environmental Defense, and the Sierra Club. Last year, Greenpeace spokesman Rick Hind told the New York Times, “If there’s nothing else and it’s going to save lives, we’re all for it. Nobody’s dogmatic about it.”

That’s easy to say now. But what about all the people who died when groups like Greenpeace dogmatically refused to budge on the ban? Might an apology be in order?

Junk-science debunker Steven Milloy, an adjunct scholar with the Competitive Enterprise Institute, wonders why the environmentalists took so long to change their minds.

“There are no new facts on DDT — all the relevant science about DDT safety has been available since the 1960s,” Mr. Milloy said.

Mr. Milloy adds, “It might be easy for some to dismiss the past 43 years of eco-hysteria over DDT with a simple ‘never mind,’ except for the blood of millions of people dripping from the hands of the World Wildlife Fund, Greenpeace, Rachel Carson, Environmental Defense Fund, and other junk science-fueled opponents of DDT.”

Mr. Milloy reminds us that the same people who spread DDT hysteria are now pushing the global-warming scare. “If they and others could be so wrong about DDT, why should we trust them now?”

That’s a fair question. For now, let’s celebrate the coming elimination of malaria in Africa.

Mr. Stossel is co-anchor of ABC News’s “20/20” and the author of “Myth, Lies, and Downright Stupidity: Get Out the Shovel — Why Everything You Know is Wrong.”