The first to have a heart attack was George Kull Jr., 56, a millwright who worked for three decades at the steel mills in Lackawanna, N.Y. Three weeks after learning that his plant was closing, he suddenly collapsed at home.

Less than two hours later, he was pronounced dead.

A few weeks after that, a co-worker, Bob Smith, 42, a forklift operator with four young children, started having chest pains. He learned at the doctor’s office that he was having a heart attack. Surgeons inserted three stents, saving his life.

Less than a month later, Don Turner, 55, a crane operator who had started at the mills as a teenager, was found by his wife, Darlene, slumped on a love seat, stricken by a fatal heart attack.

It is impossible to say exactly why these men, all in relatively good health, had heart attacks within weeks of one another. But interviews with friends and relatives of Mr. Kull and Mr. Turner, and with Mr. Smith, suggest that the trauma of losing their jobs might have played a role.