IT WAS THE WORST INDUSTRIAL accident in United States history. On April 16, 1947, a fire aboard the Grandcamp, a French freighter docked at the port of Texas City, ignited the ship’s cargo, and the ensuing explosions killed more than 580 people. The cargo was ammonium nitrate—the same substance used as ordnance by the U.S. military during World War II and in 1995 to bomb the Oklahoma City federal building—and the explosive force of the 2,300 tons of “fertilizer” leveled the Texas City docks, destroyed some one thousand homes and businesses, and injured about 3,500 residents. The concussive force was felt up to eighty miles away and caused a fifteen-foot tidal wave. Dozens of fuel tanks and two more ships blew up as well, sending chunks of metal and concrete flying. The Grandcamp’s own 1.5-ton anchor was found almost two miles away.

Even fifty years later, the town’s dark history hangs over it as thickly as did the greasy smoke that morning. In a new book, The Texas City Disaster, 1947 (University of Texas Press, $30), Hugh W. Stephens blames “complacency, neglect, ignorance, and even stupidity amid dangerous circumstances.” No wonder, as even the BBC prepares to take note of the anniversary, and as Texas City itself gears up for a solemn commemoration, some residents are cringing. “I was introduced to a lady the other day,” says Meriworth Mabry, the town’s unofficial historian, “and when she asked where I was from, I steeled myself for the usual response. Instead, she said, ‘Oh, Texas City—my husband and I went there once to watch shorebirds.’ I almost hugged her.”

Perhaps because of Texas City’s reluctance to dwell on culpability, the disaster has been examined largely in terms of human tragedy. One such dramatic story is that of Savas Saragoza, who was then ten years old. “A cousin wanted me to ride my bike down to the docks to see the fire up close,” he recalls, “but I chickened out. So I was raking leaves in my front yard and admiring the pretty smoke, which had an orange glow.” Then the blast hit. The cousin survived, but not until the next day did Saragoza learn the fate of his injured father, an office worker on the docks who later died of gangrenous infection. The experience launched Saragoza on a lifetime of community service: Now sixty, he is the senior captain of the Texas City Police Department.

Eventually, other kinds of good also sprang from the bad. The 1947 explosions led directly to the creation of disaster-preparedness and disaster-relief plans on both the state and the national levels. The docks are again bustling with boats and ships—and studded with safety-first signs. Not just rebuilt but revitalized, Texas City is determined to overcome its dirty-and-dangerous image. In recent years it has, among other feats, tripled its park acreage, modernized its firefighting system, and—best of all, for a city built on petroleum—won national awards for clean air and water. “We can’t change the past,” says Mayor Charles Doyle, “but we can change the future.”