(CNN) Five oil rig workers were missing after an explosion Monday in an Oklahoma gas well, Pittsburg County Sheriff Chris Morris said in a press conference.

Seventeen employees were rescued but "five are still unaccounted for at the well," Morris said.

Sixteen people had no injuries or minor injuries, and one person was flown by medical helicopter to a hospital in Tulsa, officials said.

Emergency responders received a call reporting the gas well explosion at 8:45 a.m. local time.

The location was on fire, and crews were pulled back after several explosions, said Pittsburg County Emergency Management Director Kevin Enloe.

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