MEXICO CITY (AP) — Inside the maternity hospital on the western edge of Mexico City, concern quickly turned to panic as the sour smell of propane seeped in and a vapor cloud grew at the emergency room's entrance. Neighbors who rushed to the scene found bleeding mothers carrying newborns out of the wreckage hospital while babies cried in the rubble. Mayor Miguel Angel Mancera said the gas truck driver and two other employees of the Express Nieto company were hospitalized and in custody. Up to 80 percent of Mexicans use propane rather than natural gas delivered by mains, and highly explosive liquified propane is distributed to homes and businesses either by trucks like the one that exploded or in cylinders, said Margarita Palma of Amexgas, a trade association of Mexico's propane distributors. The blast occurred at 7:05 a.m.