Mexico City ? At least 18 oil workers were killed when a drilling rig hit an oil platform in stormy weather, spilling gas and oil into the Gulf of Mexico, the state-owned oil company said Wednesday. Seven workers were still missing.

Rescuers have pulled 61 oil workers to safety from storm-tossed waters but have yet to control the oil leak, Mexico’s oil monopoly Petroleos Mexicanos, or Pemex, said in a news release.

One survivor, Eder Ortega Flores, 25, told the Televisa television network that workers abandoned the rig amid 25-foot waves only after leaking gas rose to unbearable levels and the supply of air from emergency breathing devices ran out. Once in the water, waves battered the workers’ life rafts.

“The life rafts didn’t hold up under the force of the waves,” he said.