Clark County firefighters evacuated four floors of the Rio about 3:30 p.m. Wednesday after a mattress caught fire on the hotel's 38th floor.
County spokeswoman Stacey Welling said firefighters treated two hotel employees for smoke inhalation. They were taken to Spring Valley Hospital Medical Center. The employees had tried to enter the room to put out the fire, she said.
The fire was confined to the mattress on the 38th floor but smoke spread to several floors. Floors 36 through 39 were evacuated as a precaution, Welling said in a news release.
She said sprinklers activated and contained the fire to the room.