Officials at Mexico's state-run oil company say they are searching for three missing workers from a platform fire that killed four others, and are beginning to restore production at the damaged gulf facility.

Exploration and production director Gustavo Hernandez says Petroleos Mexicanos, or Pemex, has help from the Navy in the search and rescue, and expects to restore 80 percent of production in the next week.

Estimated production of 646,000 barrels of crude a day and 1.4 billion cubic feet of gas in the region won't be affected by the fireball that hit the processing platform Wednesday, Hernandez said Sunday.

Some 301 workers were evacuated and 45 sought medical attention.

There was no significant oil spill because the feeder lines could be turned off. Pemex is still investigating the cause.