NEW ORLEANS — The Coast Guard was searching Friday for two workers missing after a fire erupted on an oil platform in the Gulf of Mexico, sending an ominous black plume of smoke into the air reminiscent of the 2010 Deepwater Horizon explosion that transformed the oil industry and life along the coast.

The fire, begun while workers were using a torch to cut an oil line, critically injured at least four workers who had burns over much of their bodies.