The explosion roared north up West 117th Street, erupting through the pavement. Flames leaped from the ground. Cars, sidewalks, hunks of concrete and manhole covers flew into the air. Some witnesses feared an atomic bomb had dropped on Cleveland and Lakewood during evening rush hour on Sept. 10, 1953. Instead, a mile-long sewer line had burst. One woman died and 64 people were injured. Margaret Mahoney, the state’s new director of industrial relations, came to town to investigate. A feisty former state senator, she’d accused wartime arms plants of hoodwinking older would-be Rosie the Riveters by only hiring young women — a charge based on her own failed quest for a job with the war effort. Mahoney directed a three-man state gas detection squad as they ran tests in the blast craters at West 117th and Clifton Boulevard, right in front of the present-day Diner on Clifton, then a Tastyburger Systems restaurant. In the end, investigators ruled out natural gas wells and ordinary sewer gases as possible causes of the blast. An expert panel blamed flammable and volatile waste that local manufacturers had dumped in the sewer.