Tanigawa, the Public Health Department chairman at Ehime University’s medical school, said he met and spoke with 80 of the workers over four days when he was allowed into another nearby nuclear plant where many of them take their breaks. He said he was not able to carry out full physical exams on the workers before leaving Tuesday because of time constraints…

“Because they sleep so close to each other, snoring is a big problem,” he said. “Normally, that might sound funny, but in this case it is denying people sleep and that can lead to bad performance on the job.”

The workers, most of them middle-aged men, suffer insomnia and show signs of dehydration and high blood pressure, he said. One had gout. Tanigawa said he is concerned they may develop depression or heart problems.