THREE weeks after Japan's earthquake and tsunami crippled the Fukushima nuclear power plant, spewing radiation as far as Iceland, clean-up crews have been working around the clock to bring the reactor under control and contain the leakage. Their life is a nightmare. "Crying is useless," wrote one worker in an e-mail to a colleague. "If we are in hell, all we can do is crawl up to heaven."

Workers who were already facing deadly radiation exposure were forced to sleep on a floor with barely enough to eat and drink, until the Japanese media exposed their terrible conditions. Some workers were sent into the toxic plant without basic protective gear like rubber boots, and needed to be hospitalised. On April 1st the government revealed that the plant's operator, TEPCO, had not even provided dosimeters—small, inexpensive badges that record radiation exposure—to all workers.

The fear and danger is beyond comprehension for most people, and in particular the political leaders who must order men in to danger. But interestingly, it is not unfamiliar to former American president Jimmy Carter. Nearly half a century ago, as a young naval officer, he led a 23-man team to dismantle a reactor that, like Fukushima, had partially melted down.

The reactor in Chalk River, Canada, about 180 kilometres (110 miles) from Ottawa, was used to enrich plutonium for America's atomic bombs. On December 12th 1952 it exploded, flooding the reactor building's basement with millions of litres of radioactive water. Lieutenant Carter, a nuclear specialist on the Seawolf submarine programme, and his men were among the few people with the security clearance to enter a reactor. From Schenectady, New York, they rode the train up and got straight to work.

"The radiation intensity meant that each person could spend only about ninety seconds at the hot core location," wrote Mr Carter in "Why Not the Best?", an autobiography published in 1975 when he was campaigning for the presidency.

The team built an exact replica of the reactor on a nearby tennis court, and had cameras monitor the actual damage in the reactor's core. "When it was our time to work, a team of three of us practised several times on the mock-up, to be sure we had the correct tools and knew exactly how to use them. Finally, outfitted with white protective clothes, we descended into the reactor and worked frantically for our allotted time," he wrote. "Each time our men managed to remove a bolt or fitting from the core, the equivalent piece was removed on the mock-up."

"For several months afterwards, we saved our feces and urine to have them monitored for radioactivity. We had absorbed a year's maximum allowance of radiation in one minute and twenty-nine seconds. There were no apparent after-effects from this exposure—just a lot of doubtful jokes among ourselves about death versus sterility," Mr Carter wrote.

The men at Fukushima face similar risks. Some 21 workers have been exposed to more than 100 millisieverts of radiation, the maximum permissible during an emergency, according to Japan's Nuclear and Industrial Safety Agency (NISA). As a result, NISA raised the limit to 250 millisieverts for plant workers. At 500 millisieverts the exposure begins to have detectable effects on health.

In 2008, when Mr Carter was 83, he was asked if he had been scared. The former president grew quiet and, speaking very deliberately, replied: "We were fairly well instructed then on what nuclear power was, but for about six months after that I had radioactivity in my urine. They let us get probably a thousand times more radiation than they would now. It was in the early stages and they didn't know." The account, from Arthur Milnes, a journalist and historian at Queen's University in Canada, appears in a book published last month, "Jimmy and Rosalynn Carter: A Canadian Tribute" (McGill-Queen's University Press, 2011). "I learned the dangers," said Mr Carter.

People close to Mr Carter credit his Chalk River experience for his decision not to develop a neutron bomb and to restrict plutonium enrichment to prevent nuclear proliferation. And it is considered one of the principal reasons he took quick, precautionary actions during the Three Mile Island reactor crisis, which occurred two years into his presidency. As for the Chalk River disaster itself, some of today's reactor safety features came out of the incident, such as a system for independent, fast shutdowns that is separate from the regular reactor controls.

Fukushima had this feature. But the system failed due to poor planning. Back-up generators were placed on the plant's ocean-facing side and at basement level. The tsunami's waters flooded everything, and disabled the back-up power for cooling the reactor.

The Economist has contacted Mr Carter's office with questions for the former president about the Chalk River incident, advice to workers at Fukushima and his views on international regulation during nuclear crises. If we hear back from Mr Carter, we'll write a follow-up post.